Farmed Tilapia and Catfish are More Like Chicken than Fish

Fish are heart-healthy foods because they usually have high levels of omega-3 fatty acids and low levels of omega-6's.. However, researchers at Wake Forest University School of Medicine show that farm-raised tilapia and catfish contain less than one-eighth the amount of omega-3's found in farmed salmon or trout. The tilapia and catfish also had much larger amounts of omega-6 acids than salmon or trout. The ratio of omega-6 to omega-3 in tilapia and catfish averaged 11 to one, about the same as that of chicken (Journal of the American Dietetic Association, December 2008).

A crucial part of a healthful diet is the ratio of omega-6s to omega-3s. Your immunity is supposed to be good for you by killing gems before they can harm you. However, if your immunity stays active, it starts to attack your own body to increase risk for heart attacks, certain cancers and even asthma and some types of arthritis. Omega-3 fatty acids produce prostaglandins that turn down your immunity to help prevent inflammation and the health problems it can cause. Omega-6 fatty acids promote inflammation. A major explanation for the high heart attack rate in North Americans is the high ratio of omega-6s to omega-3s in the diet that contains lots of omega-6s from vegetable oils and low amounts of omega-3's found in fish and seeds.

Few species of fish can grow and thrive on a diet of corn and plant oils. Salmon, trout and most other farmed fish must be fed fish meal and fish oils, which are good sources of omega-3's. However, tilapia and catfish can be raised on corn alone. Since corn-fed tilapia are inexpensive and abundant, they are the fifth most popular fish in America and are widely used for fish sticks, fish burgers and artificial crab (surimi). These are perfectly good foods, but to get the full benefit of omega-3's in seafood, choose oily fish such as salmon, trout, tuna, sardines, anchovies, mackerel or herring. More on omega-3's

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Nuts Combat Metabolic Syndrome (Syndrome X)

Nuts are concentrated sources of fat and calories, but they are high in monounsaturated fats which are healthful. A new study from Spain shows that adding nuts to a Mediterranean diet helps to reverse Metabolic syndrome, defined as having three or more of the following: 1) abdominal obesity, 2) high triglycerides, 3) low HDL (good) cholesterol, 4) high blood sugar and 5) high blood pressure. More than 20 percent of North Americans have metabolic syndrome and are at high risk for diabetes. Many of these people will die prematurely, usually from a heart attack.

This study involved 1,200 men and women from 55 to 80 who followed one of three diets for one year. Sixty-one percent of the study group had metabolic syndrome. The first group followed a low-fat diet that reduced all types of fats. The second group ate a Mediterranean diet with at least four tablespoons of olive oil a day. The third group ate the Mediterranean diet with extra nuts. At the end of the study all three groups had improved, but those eating nuts had far fewer of the factors that make up metabolic syndrome. Most did this without restricting calories or losing weight, but they were able to reduce belly fat and lower cholesterol and blood pressure (Archives of Internal Medicine, December 2008).

Fats are classified by their chemical structure into saturated, polyunsaturated and monounsaturated. Monounsaturated fats found in olives, avocados and many nuts and seeds help to prevent heart attacks. Before the bad LDL cholesterol can damage arteries, it must first be oxidize in your bloodstream. LDL cholesterol made from monounsaturated fats is highly resistant to oxidation, so it helps to prevent damage to arteries that can lead to a heart attack. The diet I recommend includes plenty of the good fats found in nuts, seeds, beans, whole grains, olives, avocados, fish and shell fish.

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Understanding Delayed Muscle Soreness

If you exercise properly, you are supposed to work hard enough to damage your muscles so they feel sore on the next day. This is called delayed-onset muscle soreness. You should then exercise at reduced intensity for as many days as it takes for the soreness to go away.

An article from St Mary’s University College in New Zealand reviews scientific studies on exercise-induced muscle damage (Sports Medicine, December 2008). When muscles feel sore from exercise, they are swollen and leak proteins from inside their cells into the bloodstream, and they cannot generate their usual force. You really have no choice. You must put far less pressure on sore muscles or you will injure them, delaying recovery and your ability to exercise intensely again.

Sore muscles heal faster if you take the next day off, but exercising gently during recovery will make your muscles more fibrous so they can withstand more pressure when you take your next intense workout.

Eating foods with protein and sugar within four hours after you finish a hard workout helps muscles recover faster. The sugar raises insulin levels which helps to drive protein into the muscle cells to promote healing.

Aspirin and nonsteroidals such as ibuprofin may help reduce muscle soreness, but they can delay healing. Stretching and massage make your muscles feel better but there is little evidence that they make you recover faster. Studies of electrical muscle stimulation and cold therapy (ice packs) are so inconsistent that most exercise researchers do not recommend them. On the other hand, virtually everyone agrees that each bout of intense, muscle-damaging exercise followed by reduced intensity exercise makes muscles stronger.

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Cold weather may increase risk for various health problems

Nobody really knows why, but recent research show that sudden drops in environmental temperature are associated with increased risk for disease and death (American Journal of Epidemiology, December 2008).

Researchers at the University of Athens in Greece studied people in 15 European cities. They plotted the average temperature for that day against the number of deaths in that city and showed that a 1?Centigrade decrease in temperature from one day to the next is associated with a 1.72 percent increase in daily heart attack deaths, a 3.30 percent increase in respiratory deaths, and a 1.25 percent increase in stroke deaths.

This study does not tell you to move to warmer climates because those who live in warmer cities are far more susceptible to dying from sudden drops in temperature. This study does suggest that you should try to avoid chilling and cold weather if you suffer from heart, lung or blood vessel disease.

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Exercisers Age Better

Athletes who compete into their eighties suffer few medical problems, but those who lapse into inactivity regress toward the general population norms for fitness, weight control and health problems, according to a study in the Clinical Journal of Sport Medicine (November 2008).

People who compete into later life in sports such as running or cycling can maintain their competitive edge into their eighties. Each muscle is made up of millions of muscle fibers. With aging, particularly after age 50, you lose muscle fibers so you become weaker. You cannot slow the loss of muscle fibers, but you can compensate for the loss of fibers by increasing the size of each remaining muscle fiber with regular vigorous exercise. If the results of this study can be extended to all regular exercisers, you can also expect to live longer and suffer fewer health problems than your non-exercising peers.

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Eggs Increase Risk for Diabetes?

Research from Harvard Medical School suggests that eating an egg a day may increase a person’s risk for developing diabetes (Diabetes Care, December 2008). This is the first large study to support the general belief that eating eggs frequently may harm you. However, animal studies have failed to show any association between eating eggs and diabetes, and the authors of this study did not offer any explanation for the increased risk.

The authors studied 20,703 male physicians without diabetes from the Physicians' Health Study (1982-2007) and 36,295 non-diabetic female health professionals from the Women's Health Study (1992-2007). The men were followed for 20 years and the women for 11 years. Men who ate seven or more eggs per week were 58 percent more likely to develop type 2 diabetes, and women eating a similar amount were 77 percent more likely to become diabetic than those who did not eat eggs. Risk for diabetes was lower when fewer eggs were eaten (9 percent for one egg per week, 18 percent for two to four eggs and 46 percent for five to six eggs).

This was a self-reported study so it is possible that the people who eat eggs also have other habits that increase their risk. For example, they may be more likely also to eat meat, which may increase diabetes risk, as I reported in the November 9 issue of the eZine.

An egg is a very rich source of saturated fat (1.5 grams) and cholesterol (200 mg), but adding three eggs per day to the average Americans’ diet does not raise cholesterol levels. Cholesterol in eggs has very little effect on blood cholesterol levels in healthy adults. Several studies show no relationship between eating eggs and increased risk for heart disease or stroke and most people can eat one egg a day without increasing heart disease risk. (Journal references for these studies) I eat eggs 2-3 days per week and will continue to do so unless more persuasive research comes along.

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Eating Before Exercise OK for Most People

Many people believe that exercising right after you eat will cause stomach cramps, but that doesn't usually happen. Whenever your stomach fills with food, its muscles contract and require large amounts of blood. When you exercise vigorously, your heart pumps large amounts of blood to your skeletal muscles. If your heart is not strong enough to pump blood to both your stomach and your skeletal muscles, blood is shunted from your stomach muscles, the muscles lack oxygen, lactic acid builds up in muscles and they start to hurt. However, most people can exercise after eating without suffering cramps because their hearts are strong enough to pump blood to both their exercising muscles and their stomach muscles.

Some researchers believe that you shouldn't eat sugar before you exercise because it will cause your blood sugar level to rise and your pancreas to release insulin, which will cause your blood sugar to drop too low so you will feel tired during exercise. However, the major cause of tiredness that you feel in your muscles during exercise is lack of stored sugar in muscles. Taking any extra calories before and during exercise helps to preserve the sugar that is stored in muscles and help you to exercise longer. If you are going to exercise for more than an hour, eat or drink anything you like before and during your exercise. Most people will not get stomach cramps while exercising, no matter what or when they eat.

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Lifting Weights Does Not Hamper Children's Growth

Lifting weights before puberty growth does not prevent children from growing to their full potential height. Bones grow from growth centers that are weakest part of bone, but strength training during growth does not damage these growth centers and children who lift weights in programs with experienced supervision do not suffer more injuries than adults. There used to be concern that growing large muscles would make people musclebound and interfere with coordination, but this does not happen. With increased strength comes increased speed and increased coordination in movements requiring strength.

Having large strong muscles makes you a better athlete. Muscle growth is limited by the size of the bones on which they attach, so the larger the bone, the stronger the muscle. Children who start to play tennis before they go into puberty have larger bones in the arm that holds the racquet. They also have larger bones in their tennis arm than those who start to play tennis later in life. The larger and stronger your muscles, the harder you can hit a tennis ball. The best time for future Olympians to start training is while their bones are still growing.

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Reduce Belly Fat with Intense Exercise

Researchers at the University of Virginia show that intense exercise is far more effective in reducing belly fat than less intense exercise (Medicine & Science in Sports & Exercise, November 2008).

Storing fat primarily in your belly usually means that you have very high insulin levels which increase risk for heart attacks, strokes, diabetes, metabolic syndrome and even some cancers. Insulin causes fat to be deposited in your belly.

Exercise makes muscles more sensitive to insulin so that you need less to do the same job. The more intensely you exercise, the more sensitive muscles become to insulin. You cannot exercise intensely every day because intense exercise damages muscles and you have to allow time for muscles to recover. However, you can check with your doctor to make sure that you do not have a health problem that can make exercise unsafe for you. If you pass, try to exercise intensely at least once a week.
Newsletter

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Why Migraines May Reduce Breast Cancer Risk

Few migraine sufferers can see any bright side to their pain, but now we have one study showing that a history of migraines is associated with a lower risk for breast cancer. The report appears in Cancer Epidemiology, Biomarkers & Prevention (November 2008). Researchers pooled data from two studies of postmenopausal women to compare odds ratios among 1900 with breast cancer and 1400 controls. Women who had migraines showed reduced risks for ductal and lobular carcinomas, especially hormone-receptor–positive tumors.

One of the triggers for migraines is a sudden drop in estrogen that causes a drop in brain levels of serotonin, the neurotransmitter that makes you happy and smart. Premenstrual syndrome occurs when the sudden drop in estrogen in the later part of the menstrual cycle causes a drop in serotonin that can make some women sad and depressed. Women who suffer migraines may have lower levels of estrogen, the female hormone that can stimulate breast cancers to grow.

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Inflammation: More Important than Cholesterol

At the American Heart Association conference in New Orleans, researchers from the Jupiter study reported that statin drugs caused people with normal cholesterol but with high C-reactive protein levels to suffer 54 percent fewer heart attacks, 48 percent fewer strokes, 46 percent fewer angioplasties or bypass operations and 20 percent fewer deaths from any cause than those taking placebos (NEJM, November 9, 2008). The results were so dramatic they made the front page of the New York Times, Washington Post and many other newspapers.

A C-reactive protein test (CRP) measures inflammation. Inflammation is caused by anything that keeps your immunity active such as chronic infections or anything that damages tissue such as smoking, having high cholesterol or high blood pressure. Last week I reported a theory to explain why eating mammal meat causes inflammation and is associated with increased risk for premature death, cancers and heart attacks. Meat contains a molecule called Neu5Gc that humans do not have, so the immune system of humans attacks this protein as if it was an invading germ and eventually attacks the host itself to destroy the blood vessels and increase risk for heart attacks and strokes.

Many scientists feel that inflammation is a stronger predictor of heart attacks than high cholesterol levels. At present, statins are prescribed to treat people with heart disease or high cholesterol. This study shows that they prevent heart attacks in people with high CRP and normal cholesterol levels, presumably because statins reduce inflammation. About 7 million people in the US have normal cholesterol and high CRP. Treating them with a brand-name statin would cost each $116 a month or $9.7 billion a year, and prevent about 28,000 heart attacks, strokes and cardiovascular deaths each year.

Rather than just writing a prescription for statins, I think doctors should ask why a patient's CRP is elevated and try to lower it with lifestyle changes or treatment of any underlying chronic infection.

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Still Eating Red Meat? You May Want to Reconsider

Several years ago, Professor Ajit Varki of the University of California, San Diego discovered a molecule called Neu5Gc that appears in the tissues of every mammal except humans (Proceedings of the National Academy of Sciences, September 29, 2003). Now he has put together the pieces of a puzzle that may explain why humans evolved with large brains and why, if we want to live into old age, we should probably avoid eating meat from any other mammals (Science, October 31, 2008).

His theory depends on evolution. Living creatures on earth started as one-celled organisms, progressed to 2 cells, and eventually to fish and birds. A mutation occurred in progressing to mammals, who developed the gene to make Neu5Gc. Mammals progressed to apes and Neanderthals, and as humans evolved, Neu5Gc added a single oxygen atom to become a different molecule called Neu5Ac. So Neu5Gc is found in all mammals and their milks except humans. It is not in fish or birds. Interestingly, the Neu5Ac molecule explains why humans are the only mammal to suffer from malaria. The malaria parasite cannot enter a cell until it grabs onto the Neu5Ac on the surface of human cells.

Many epidemiological studies show that people who eat red meat are at increased risk for heart attacks, strokes, at least 17 different cancers, diabetes, autoimmune diseases, arthritis and asthma. Scientists have blamed saturated fats or burnt fats, but this does not explain why red meat is linked to all of these diseases while poultry, fish or saturated fats from plants are not.

Dr. Varki proposes another theory. When humans ingest the flesh or milk of any mammal, they absorb Neu5Gc and treat it the same way as an invading germ, so they make antibodies against it. This turns on their immunity and keeps it active so it eventually attacks the host itself, the human body. This is called chronic inflammation, which can lead to heart attacks, strokes, cancers and so forth.

Since humans cannot make Neu5Gc, any amount found in human cells come from the mammals that they have eaten. Neu5Gc is found in high levels in tumors, with the highest levels in metastasizing tumors. In our food supply, Dr. Varki found very high levels of Neu5Gc in beef, pork, lamb and goat, and moderately high amounts in milk and cheese. Low levels are found in turkey, duck, chicken and eggs; and negligible amounts occur in plants and seafood.

I stopped eating meat many years ago, and this report makes me even more convinced that it should be avoided. I eat lots of fruits, vegetables, whole grains, beans and nuts, as well as fish and shellfish. Eggs, long thought to be a harmful high- cholesterol food, now appear to be a healthful dietary staple. While poultry appears to be a healthful food according to Dr. Varki's theory, I still do not eat it. I do not drink milk and now plan to limit cheese as well.

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Side Stitches

Side stitches are caused by a stretching of the ligaments that run downward from the diaphragm to hold up the liver. You breathe once for each two strides. You breathe out when one foot, usually the right, strikes the ground. So, your diaphragm goes up when the force of your foot strike causes your liver to go down. This stretches the ligaments to cause pain.

You can relieve the discomfort by stopping running and pressing your fingers deep into your liver to raise it up toward your diaphragm. At the same time, purse your lips and blow out as hard as you can against the tightly held lips. Pushing the liver up releases the stretched ligaments. Breathing out hard against resistance lowers your diaphragm. The pain usually goes away immediately and you can resume running.

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Reduce Oxidants to Lower Heart Attack Risk

A study from the University of Dundee in Scotland shows that neither antioxidants nor aspirin pills prevent heart attacks in diabetics (British Medical Journal, October 2008). Heart attacks occur when a plaque breaks off from the walls of a coronary artery and travels down an ever-narrowing artery to form a clot and block the flow of blood to the heart muscle. Aspirin helps to prevent clotting and therefore prevents heart attacks. Ibuprofen and other nonsteroidal pain medications block aspirin so they can increase clotting and heart attack risk in susceptible individuals.

One of the strongest risk factors for a heart attack is diabetes; 80 percent of diabetics die of heart disease. Diabetes could be such a strong risk factor for heart attacks that aspirin does not prevent it, or it may be that aspirin should be prescribed only for people with established symptomatic heart disease.

Other studies show that taking antioxidant vitamins (500 milligrams of vitamin C every day, 600 units of vitamin E every other day or 50 milligrams of beta carotene every other day) does not prevent heart attacks (Archives of Internal Medicine, August 2007). As of today, there is no evidence that taking antioxidant pills helps to prevent heart attacks. Now many scientists think that you should aim to prevent your mitochondria from making excessive amounts of oxidants. The cells of your body have tiny chambers in them called mitochondria that help convert food to energy. When they do this, they knock of electrons from nutrients, and these extra electrons can eventually end up attached to oxygen. Electron-charged oxygen, called reactive oxygen species or free radicals, then attach to the DNA in cells to damage them and shorten life.

At this time, the only practical ways to reduce the amount of oxidants produced by mitochondria are exercise or calorie restriction with adequate nutrients. Both help the mitochondria burn food to produce fewer oxidants. In the future the same effect may be accomplished with chemicals, such as resveratrol or dichloroacetate, but studies of these substances in animals have not yet been successfully applied to humans.

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Exercise-Induced Asthma

We have known for more than 25 years that exercise-induced asthma is caused by breathing dry, cold air, but for the first time we may know why this happens. Researchers at the Naval Medical Center-San Diego have just shown that exercise-induced asthma is associated with diminished secretion of lung mucous (Chest, September 2008). These same people also produce far less saliva, sweat and tears.

So when certain susceptible people breathe hard and fast, in air that is cold and dry, the bronchial tubes are not protected by an adequate supply of mucous in their lungs. This irritates the bronchial tubes to cause wheezing, coughing and shortness of breath. People who are least likely to suffer exercise-induce asthma would therefore be those who produce large amounts of lung mucous, sweat, saliva and tears.
Late-onset asthma in adults

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Eat More Fish and Less Vegetable Oil

The Japanese have the lowest incidence of heart attack in the world, yet they have the same rates of high cholesterol, high blood pressure and diabetes, and they smoke as much as Americans do. It's not because of their genes because Japanese who move to Hawaii and the continental United States have a significant rise in their heart attack rates and the same amount of plaques in their arteries as Americans (Journal of the American College of Cardiology, August 5, 2008).

On the average, Japanese in Japan eat fish eight times a week and they add far less vegetable oils to their prepared foods. This study shows that Japanese living in Japan have twice as much long-chain omega-3s in their blood as those who left Japan. They also have lower blood levels of omega-6 polyunsaturated fatty acids, and fewer plaques in their arteries.

Fats are classified by their chemical structure into saturated, polyunsaturated, and monounsaturated. Polyunsaturated fats are further sub-classified into omega-3, omega'6 and omega-9. Increasing the ratio of omega-6s to omega-3s increases heart attack risk. For two million years, the typical human diet contained a ratio of omega-6s to omega-3s of about two to one. Today we take in large amounts of omega- 6s in the form of extracted vegetable oils and not enough omega-3s from fish, shellfish and some seeds. Now our ratio of omega-6s to omega-3s has risen beyond 12 to one.

We now think that heart attacks are caused to a large extent by an overactive immunity called inflamation. Your immunity is supposed to protect you from infection. However, if your immunity stays active all the time, it attacks you and starts to destroy every tissue in your body, particularly your blood vessels. Omega-3s form certain chemicals in your body called prostaglandins that turn off your immunity. Omega-6s form prostaglandins that turn on your immunity. The activity of your immunity changes with the ratio of omega-6s to omega-3s. For a heart-healthy diet, add more seafood and whole seeds, and eat less of the foods made with polyunsaturated vegetable oils.

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Overweight is not Destiny

Nobody has to be fat, but some people may have to exercise for many hours just to control their weight. For example, a gene associated with fatness has been identified in the Amish who live near Lancaster, PA. A study from the University of Maryland shows that Amish men with that obesity gene who burned more than 980 calories per day through physical activity were not fat. The same applied to women who burned more than 860 calories per day (Archives of Internal Medicine, September 2008).

Exercise causes you to eat more food, but when you are very active, you do not increase the amount of calories to equal what you burn. For example, if your exercise program causes you to burn 1000 more calories per day, you will usually increase your food intake by about 500 calories, and probably significantly less than that. More

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Check Vitamin D Levels this Winter

In this newsletter I have reported that low vitamin D levels are associated with increased risk for heart attacks, strokes, at least 17 different cancers, diabetes, autoimmune diseases, depression and osteoporosis. Adequate blood levels of vitamin D are thought to be over 75nmol/L. Researchers at the University of Toronto have now shown that in the winter, more than 93 percent of the people in Toronto have concentrations below 75 nmol/L, and 75 percent have concentrations below 50 nmol/L (BMC Public Health, September 26, 2008).

Only those with light skins had average vitamin D intakes exceeding the current Recommended Adequate Intake (RAI = 200 IU/day). Those with dark skin and/or excess weight had very low levels of vitamin D. Dark skin blocks ultraviolet light. Obesity sequesters vitamin D so it is not available for use. Aging also lowers vitamin D levels as the skin of older people doesn't make vitamin D as well as during younger years.

In the wintertime, I recommend getting a blood test called D3. If it is below 75 nmol/L, you need more sunlight or vitamin D pills. The blood test for the active form of vitamin D (1,25 dihydroxy-vitamin D) is of little value as it often is normal when a person has a severe deficiency. Lack of vitamin D causes the parathryroid gland to produce massive amounts of parathyroid hormone that causes these falsely high levels. More on vitamin D

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Stretching Pros and Cons

Researchers at the University of Sydney in Australia reviewed the world's literature and concluded that stretching does not prevent muscle soreness that follows vigorous exercise (1). Athletes train by taking a hard workout, feeling sore the next day, and then taking easy workouts for as many days as it takes for the soreness to go away. Since stretching does not reduce muscle soreness, it will not help you to recover faster from hard exercise. The best way to recover from exhausting competition is to move with little pressure on muscles, such as cycling on a stationary bicycle (2).

Stretching does not prevent injuries (3). Muscles and tendons tear when the force applied to them is greater than their inherent strength. Anything that makes a muscle stronger helps to prevent injuries, but stretching does not make muscles stronger or faster.

Even though most high school and college coaches have their athletes stretch before games or races (4), you should not stretch before competition because it decreases muscle strength (5) and impairs your ability to run fast (6).

However, stretching can make you a better athlete. Muscles attach to bones by long fibrous bands called tendons. Stretching lengthens tendons, and the longer the tendon, the greater the force a muscle can exert on a joint (7). So stretching a tendon to make it longer allows an athlete to exert more force around a joint to help him jump higher, run faster, lift heavier or throw further (8).

References: 1-Cochrane Database of Systematic Reviews 2007, Issue 4; 2-American Journal of Physical Medicine & Rehabilitation, June 2007; 3-Clinical Journal of Sport Medicine, March 2005; 4-Clinical Journal of Sports Medicine, May 2006; 5-Journal of Bodywork and Movement Therapies, April 2006; 6-Sports Science, May 2005; 7-Journal of Sports Science, February 2006; 8-The American Journal of Sports Medicine, February 2006. Fitness newsletter

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Broken Knee Cartilage is Forever

A team of researchers at the University of Western Ontario in London, Ontario have shown that arthroscopic removal of loose cartilage and trimming of knee cartilage is no better than doing no surgery at all (NEJM, September 11, 2008). The only other study that also used sham surgery was done at Baylor Medical School and showed the same results (New England Journal of Medicine 2002;347:81-8). The procedure is done when a surgeon inserts small tubes through the skin into the knee joint and trims the edges of cartilage and removes loose pieces of cartilage from the joint.

You hear about many athletes returning to the athletic field after breaking cartilage in their knees and having surgery. However, almost all will have pain in their knees for the rest of their lives and most will eventually have their knees replaced. When you break cartilage in your knee, it will never heal.

If you hurt your knee and the pain persists, your doctor will probably order an MRI. If it shows that you have a crack in your cartilage, you should never run or jump again. When you run, the force of your foot striking the ground is transmitted up to your knee and can extend the existing cracks. Running 6-minute miles exerts a force exceeding three times body weight. Landing from a jump exerts even greater force on your knee joint. You can usually ride a bike safely because you pedal in a smooth rotary motion that exerts little force on your knee joint. Swimming is also usually safe for your knees.

If you extend the cracks in your knee cartilage, you can have pain all the time. Then it is probably time for you to have knee replacement surgery. Surgery is also indicated for a torn anterior cruciate ligament. Your knee is really two sticks held together by four bands called ligaments. You can tear any one of three of these bands and usually do quite well. However if you tear the anterior cruciate ligament, the cartilage of your lower leg is allowed to slip backwards against that of your upper leg and shear off additional cartilage, eventually necessitating a knee replacement. So almost always doctors recommend replacing a torn anterior cruciate ligament.

Contact sports that require running and jumping, such as football and soccer, are the ones that put you at increased risk for knee damage. Once you crack cartilage in your knees, you probably should avoid all sports that require running and jumping. Most people can ride or even race on bicycles and not extend their knee damage.
More on arthroscopic knee surgery

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Don't Regain Lost Weight

A new study shows that older people who diet without exercising lose huge amounts of muscle. When weight loss was combined with exercise, they did not lose muscle (Journal of Applied Physiology, October, 2008). Loss of muscle slows metabolism even further because larger muscles burn more calories at rest.

In this study, elderly sedentary people were placed in three groups: 1) Diet only, 2) exercise only, 3) diet and exercise. Those who dieted and exercised for four months lost more fat and less muscle than those who only dieted. Most of the exercisers chose to walk on a treadmill, which is not a very vigorous endeavor.

This also explains why losing weight repeatedly through dieting shortens a person's life span. Many people go on diets and lose weight, quickly regain their lost weight and then go on a diet again. These people then become fatter at the same weight because they have lost so much muscle. Therefore at the same weight, they have fuller fat cells. Full fat cells produce immune stimulant called cytokines that turn on a person's immunity continuously to cause inflammation, which increases risk for cancers, heart attacks, strokes, diabetes and other harmful diseases. More

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Plastic Bottles and Containers: New Concerns

A study from Peninsula Medical School in Exeter, U.K. shows that high levels of urinary Bisphenol-A (BPA), a chemical compound commonly used in plastic packaging for food and beverages, is associated with heart attacks, strokes, diabetes and abnormal liver tests (JAMA, Sept 17, 2008). BPA can break down to form female hormones called estrogens that are linked to breast and uterine cancer in women, decreased testosterone levels in men, and may also cause birth defects.

You are exposed to BPA, primarily through food, drinking water, tooth sealants that you may receive in a dentist's office, and exposure through your skin and lungs from household dusts. Ninety percent of Americans have detectable levels of BPA in their urines.

Although the safety of BPA is still uncertain, you would be prudent to limit your exposure. The primary concerns are plastic water bottles and baby bottles. Each bottle is supposed to have a number in a circle stamped on the bottom. Try to avoid the following numbers:
#1 Most single-use water bottles are made from polyethylene terephthalate (PET or PETE).
#7 This is used for many colorful hard plastic lexan bottles made with polycarbonate plastics.
At a minimum, do not re-use bottles or containers with these numbers. Do not freeze or reheat foods or beverages in them.

Plastic products that bear the following numbers appear to be safe:
#2 HDPE, high-density polyethylene, the most widely recyced plastic,
#4 LDPE, low-density polyethylene) and
#5 PP, polypropylene.

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Cancer: More Environmental than Genetic

More than 85 percent of the known causes of cancers are environmental, not genetic. Normal cells undergo apoptosis, a process in which each cell lives only so long and then dies. Cancer means that the DNA in cells cannot do its usual job of telling a cell when to die, so the cells grow forever and can spread to other parts of the body to kill you. Scientists have developed drugs and other treatments to destroy the process that makes cancer cells immortal. However, each cancer cell has hundreds, and even thousands, of different pathways that they can use to make them live forever. Pancreatic cancer cells have an average of 63 mutations (Science, September 4, 2008), and a brain tumor called glioblastoma has at least 47.

So when scientists develop a drug to kill a cancer, the drug acts on one or more pathways and may temporarily inhibit the cancer, but drugs never block all the pathways that can go wrong. Therefore cancer can always come back. That is why doctors often use as many as five different drugs to treat some cancers because they want to block as many of the different pathways as possible.

At this time, I believe that the best approach is to avoid or limit your exposure to known or suspected environmental triggers for cancers, which include:

- meat, particularly beef (eating red meat is associated with increased risk for 17 different cancers)
- barbecued, grilled or deep-fried foods (browning or burning foods, particularly fats or starches, forms carcinogens)
- BPA (Bisphenol A) in some plastics
- PCB's
- lead in any form
- molds such as aflatoxin from rotten peanuts or grains
- arsenic in well water
- asbestos in old buildings
- sexually transmitted diseases such as hepatis C that causes liver cancer or HPV, the human wart virus that causes cervical cancer
- formaldehyde or carbon tetrachloride
- Helicobacter pylori (bacteria that cause stomach burning and ulcers) which can cause stomach cancer
- unnecessary X rays, particularly CAT scans
- heavy exposure to pesticides
- radon from the ground leaking into your house
- tobacco in any form
- second-hand smoke
- alcohol (more than three drinks a day increases cancer risk)
- exposure to uranium
- excessive UV radiation (too much sunlight)
- not enough sunlight (lack of vitamin D)
- night shift work (depresses melatonin, a cancer-preventing hormone)

Other cancer risk factors include lack of exercise, excess weight, lack of fiber in the diet, a diet that is low in vegetables, early puberty in women (before age 12), late menopause (after age 55) or taking estrogen after menopause. In 2008, cancer will take the lives of about 230,000 more Americans than it did in 1971. Try not to be one of them.

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Limit All Sugared Drinks, Not Just HCFS

High-fructose corn syrup (HFCS) contains approximately 59 percent fructose and 41 percent glucose, while fruits juices contain a ratio of 50 percent glucose to 50 percent fructose. There really is no difference. HFCS is no better and no worse than any sugared beverage or fruit juice, it is just cheaper. When manufacturers process corn for oil, the residue is a sugary liquid that used to be thrown away. In the 1950s, soft drink makers discovered that HFCS could be added to sweet drinks at a fraction of the cost of cane sugar. Then scientists noticed that Americans have gotten progressively fatter from the 1950s to the present. This is the same period that HFCS was added to the American diet.

In the following years, many respected scientists tried to link HFCS to the obesity epidemic. However, we now have multiple studies showing that any kind of sugar in liquid form can make you fat (American Journal of Clinical Nutrition, May 2008). When you eat sugar in solid form, such as in a cookie, you eat less of other foods because the solid food fills you up. However, in liquid form, sugar supplies calories without making you feel full. When you drink any liquid containing sugar, you do not reduce your intake of food to compensate. Sugar in liquid form is not recognized by your brain as extra calories and therefore does not suppress appetite.

Today almost all researchers agree that HFCS is no worse than any other liquid sugar. All forms of sugar-water can make you fat. That includes fruit juices, sugar added to your coffee or tea, and any other sugared drinks.
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Burning Feet while Cycling

Many cyclists suffer from "burning foot syndrome", pain on the bottom of the feet, particularly during a long ride. After years of this problem, I tried a simple tip from RoadBikeRider, a free weekly newsletter from some of America's best long distance bicycle riders: Ed Pavelka, Fred Matheny, and Lon Halderman. They suggest moving the cleats back as far as possible toward the arch of the foot. All of the other articles I have read and all of the experts I have consulted recommend that you set your cleats on your shoes so that the ball of your big toe is exactly aligned with the axle of the pedal. Following Lon Haldeman's advice, I moved my cleats back last week and my feet have stopped burning. I also think I am riding faster.

This flies in the face of what other experts claim: the further back your cleat, the less power you get from your calf muscle. That's just not true. More than 90 percent of the pressure on your pedals comes from your thighs, not your lower leg (calf) muscles. The pain is caused by the front part of the foot pressing on the pedals. Moving the cleat backward takes the pressure of the forefoot and relieves the pain. As Haldeman states, you actually can be in better shape when you don't have burning feet, and you can train further and ride faster. (To subscribe to their free newsletter go to http://www.roadbikerider.com)

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Cracked skin on your heels

If you have painful cracks in the skin on your heels, try applying tape across the split skin to limit movement of the cracked edges. Let the tape fall off, as pulling it off may tear the skin even more. Friction irritates the cracks, causing more pain, so avoid loose slip-on shoes, sandals or any other footwear that causes friction. Do not file the skin as this can cause even greater thickening (called the Koebner phenomenon) that leads to cracking.

Your podiatrist can prescribe topical medications, such as urea-based creams or cortisone creams, to help heal the cracks. Cortisone creams should be used with caution since they can cause permanent thinning of the skin. If your symptoms are severe, your doctor may recommend cortisone injections, but again be aware of the side effects of too much cortisone. More

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Exercise benefits: new studies

This month's literature shows that exercise prevents cancers and helps to improve mental function with aging. Researchers from the University of Melbourne in Australia show that adults with memory impairment improve mental function after a six-month exercise program (JAMA, September 3, 2008). Another study, from Tokyo, shows that adults who exercise regularly and are active are less likely to develop a range of cancers (American Journal of Epidemiology, August 2008). The researchers followed 80,000 Japanese adults for up to ten years. Those who were more active had reduced risk for developing any type of cancer, particularly cancers of the colon, liver, pancreas or stomach.

This benefit was greatest in those who were not overweight, showing that exercising enough to control your weight is better than just exercising. Exercise lowers body fat and being overweight is associated with increased cancer risk. Furthermore, exercise can activate immune cells to hep prevent cancer. It also lowers certain sex hormones and insulin-like growth factors that can feed the growth and spread of tumors. Newsletter

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Nitric Oxide May Help Athletes

Should you believe claims that nitric oxide supplements will enlarge muscles and increase endurance? Actually, there are no products that contain nitric oxide because it is too unstable. However, supplements containing arginine (an amino acid) in combination with another blood vessel widener, alpha- ketoglutarate, can stimulate the blood vessels to increase production of nitric oxide. This dilates blood vessels that bring blood to muscles. Several studies show that the nitric oxide releasers may help athletes exercise longer, but the data are weak, sparse and not very impressive. If you take these supplements and do not exercise to your maximum, you are wasting your money. However, if you are already exercising as hard and as fast as you can, taking these supplements may let you do more work, which can make your muscles stronger (Medicine & Science in Sports & Exercise, December 2000).

Promoters of these supplements recommend doses of 6,000-10,000 mg per day and most athletes who use them take far more than that. Half of the athletes who took double the recommended dose suffered adverse side effects, usually nausea, stomach cramps or diarrhea. High doses may drop blood pressure which would harm performance. Blood pressure usually rises with exercise; a person with resting blood pressure of 120/80 can expect it to rise to 200/80 while jogging.

Prescription nitric oxide simulators such as Viagra can benefit men who have difficulty achieving or maintaining erections. Exercise, by itself, raises blood levels of nitric oxide (American Journal of Hypertension, August 2007). So if you want your arteries to make more nitric oxide, go out and exercise.
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Monosodium Glutamate: Weight Gain?

Many people still avoid MSG as the culprit in "Chinese restaurant syndrome", even though no scientific studies were ever able to show that MSG causes headaches, flushing, tingling or anything else. However, a recent study of Chinese peasants suggests that MSG may cause weight gain (Obesity, August 2008). The subjects were divided into three groups, based on the amount of MSG used, and those in the group that ate the most MSG were nearly three times more likely to be overweight than non-users. Previous studies on mice and rats found the same effect. Dr. Ka He, the lead author of the study at the University of North Carolina, concludes that MSG makes food taste better so people eat more.

It's not easy to avoid MSG even if you read food labels. Everyone eats significant amounts of monosodium glutamate because all foods that contain protein have a building block amino acid called glutamic acid which is converted in the body to glutamate. More

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Salt Helps to Retain Fluid

Researchers at Loughborough University in Leicestershire, UK show that the salty drinks help your body to retain fluid and therefore increase the time that you can exercise, particularly in the heat (European Journal of Applied Physiology, July 2008). They fed drinks of four different salt concentrations to competitive cyclists. The higher the concentration of salt, the less urine they produced. This shows that salt helps their bodies to retain water so they will have more fluid available to cool their bodies in the heat. However, this study showed that it did not improve their performance.

In 1942, the United States Government asked James Gamble of Harvard Medical school to set up guidelines for soldiers who must fight in the heat. His classic, impeccable experiments are still the basis for recommendations today for fluid and mineral replacements for athletes. He showed that the only mineral that needs to be replaced during exercise or other hard work in hot weather is sodium. So when you exercise in the heat, make sure that you take in extra salt, either in a sports drink or in salted foods such as peanuts or pretzels. If you are concerned about the effect of this extra salt on your blood pressure, buy a simple blood pressure cuff and take your blood pressure weekly, just to make sure that you are not taking too much salt or exercising too little.

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More exercise, less high blood pressure

People who continue to exercise throughout their lifetimes are far less likely to develop high blood pressure and the more they exercise, the less likely they are to develop high blood pressure (Journal of Hypertension, June 2008). In various studies, up to 91 percent of the North American population suffers from high blood pressure which puts them at markedly increased risk for strokes, heart attacks, kidney damage and arteriosclerosis. Virtually all scientists agree that this frightening incidence of high blood pressure is caused by lifestyle, and the major lifestyle factors are lack of exercise, obesity, and eating too many calories, refined carbohydrates and saturated fats.

For some people, but not all, increased intake of salt also contributes to high blood pressure. However, if you exercise, you need to take in extra salt since salt is the only mineral that you lose in large amounts through sweating. Low salt levels can cause muscle damage, fatigue and depression. Salt deficiency can also raise high blood pressure because it causes your kidneys to produce large amounts of renin and your adrenal glands to make more aldosterone. These hormones constrict arteries to raise blood pressure.

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Measure Abdominal Fat, Not Just Weight

Researchers at the University of Michigan report that not all people who are fat are at high risk for heart attacks (Archives of Internal Medicine, August, 2008). They showed that 51 percent of overweight adults (36 million Americans) have normal blood pressure, cholesterol and blood sugar, while 25 percent of normal- weight Americans (16 million) have high levels of at least two of these tests. The media picked up this study with headlines such as "Better to Be Fat and Fit Than Skinny and Unfit" (New York Times, August 19, 2008).

However, the entire study is flawed. The authors measured overweight, not abdominal obesity. If you just compare weight to height to define obesity, more than 50 percent of professional football players would be obese, and they are not. I am sure that the study would show the far more harmful effects if the authors had measured abdominal obesity rather than just weight. Storing fat primarily in your belly can predict premature death. It means that a person's insulin levels are very high and high insulin levels mean that your body is not responding to insulin so you are at increased risk for a heart attack, stroke, kidney damage, arteriosclerosis and all the other harmful side effects of diabetes.

Other studies do show that it is better to be fat and fit than out-of-shape at any weight. Steven N. Blair of the University of South Carolina showed that adults over 60 who had higher levels of fitness lived longer than unfit adults, independent of how fat they were (JAMA, December 5, 2007). He showed that fat people who were able to run on a treadmill longer than unfit, fat people had better blood tests and fewer heart attacks and deaths.

How should these studies affect you? If you are overweight, you increase your risk for heart attacks, strokes, cancers and premature death. If you store large amounts of fat primarily in your belly, you are at such great risk for premature death that you should check with your doctor and probably get a thallium stress test to see if your coronary arteries are already blocked. If they are not blocked, start a supervised exercise program and diet to lose weight and become fit. If your coronary arteries are already blocked, you will need immediate counseling about future treatment.
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Saturated fat risks cancelled by exercise

The Masai of Kenya and Tanzania eat the same type of high animal-fat diet as North Americans, but they have a very low incidence of heart attacks. In spite of the large amount of saturated fats in their diets, they have lower body weights, waist measurements, blood pressures and cholesterol levels (British Journal of Sports Medicine, July 2008). This is explained by the fact that the average Masai burns 4,000 kilocalories a day, which is roughly equal to walking 12 miles every day (this number includes the amount you burn for normal daily activities such as breathing and sleeping).

Saturated fat is the dominant fat in meat, chicken and whole milk dairy products. It raises cholesterol only when a person takes in more calories than he burns. A high-meat diet does not cause heart attacks in people who get a lot of exercise. Saturated fats are broken down by your body into two-carbon units. If you are getting too many calories, your liver converts these two-carbon units into cholesterol. If you are not getting enough calories, your body burns these units for energy.

When you take in more calories than your body needs, you store the excess as fat. Full fat cells release cytokines into your bloodstream, and they turn on your immunity. Your immunity is good because it protects you from infection, but if it stays overactive, it starts to destroy your body including your heart and blood vessels. The bottom line: if you eat much saturated fat, be sure to get plenty of exercise.
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Dieting Without Exercise Does Not Work

A new study from Israel shows us once again that dieting without exercise does not work. The participants took off only six to 10 pounds in two years. No matter what diet they were on, most regained some of the weight they lost in the early months by the end of the study (New England Journal of Medicine, July 17, 2008). It didn't make any difference whether the overweight person was on a low-fat or low-carbohydrate diet, or the healthful Mediterranean-type diet that stresses fruits, vegetables, whole grains beans, seeds, nuts and seafood. However, their small weight loss did result in improved cholesterol and blood pressure readings.

If you really want to lose weight for good, you have to exercise. Appetite is controlled in a part of your brain called hypothalamus. If you try to lose weight just by eating less food, your hypothalamus makes you miserable when you see tasty food and know that you shouldn't eat it. If you exercise, you will eat more, but you will not increase your intake of food to equal the extra calories that you burn when you exercise. After you have been exercising for a few months, your muscles will be stronger, you will feel and sleep better and you can actually start to enjoy your new activity. Then you are set for a life-long pattern of burning up the calories you take in.

Unfortunately, the majority of older people who start exercise programs drop out in the first six weeks. People are more likely to stay in an exercise program if they have company and find a sport that is fun for them. The best success comes when a husband and wife exercise together. You can also increase you chances of sticking to an exercise program by having a personal trainer, going to regular exercise classes, or joining an exercise group that is also a social club, such as Road Runners, a bicycle club or a square dancing society.

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Lifestyles Determine Who Lives Longest

According to a new National Geographic book, The Blue Zones, people live longer in the Barbagia region of Sardinia, Italy; Okinawa, Japan; Loma Linda, California (a community of Seventh-Day Adventists); and the Nicoya Peninsula in Costa Rica. The lessons drawn from these cultures are the same as those I've preached to you for the last thirty years: eat more vegetables, exercise, minimize stress, don't be overweight, and avoid smoking. Your odds also increase if you are married, live in a rural area and are a woman.

In this 1960's, people in the Georgian Republic in Russia, Abkhazians in Pakistan and the Vilcabambas in Ecuador were reported to live long lives, but it turned out that they were among the world's greatest liars, rather than the world's oldest people. The centenarians cited in The Blue Zone have documented birth certificates.

A new study from the British Journal of Sports Medicine (March 2008) found that people who exercise regularly live 12 years longer than non-exercisers, no matter where they live.

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Progress report on our training program

Several of you have asked about our training progress since I retired from my radio show and full-time medical practice. Diana and I are a 66-year-old woman and a 73-year-old man who want to ride a tandem bicycle faster than any one else in our age group. We know that training for sports requires stressing and recovering. On one day, we take a hard workout in which we ride as fast as we can, feel sore the next morning, and then go slow for as many days as it takes for the soreness to leave our muscles.

Since we often go to rallies on weekends, we usually ride very fast on Saturday and Sunday. I feel so sore on Monday that I take the day off, and then go slowly for the next four days because it takes that long for my muscles to recover. So we are doing two hard days, followed by a day off, then four recovery days and repeat the cycle. I must tell you that training depends on how you feel, so our schedules vary from week to week, depending on how sore or tired we are. There are days when we plan to ride hard, but have to take an extra easy day or even a day off, or we can expect to become injured.

It took many years for us to get up to schedule we do now. Diana had never exercised hard until she was in her late forties, so she has built up gradually over the last 17 years. She has never had a wear-and-tear injury from riding too much, but she has had three serious injuries from crashes. On the other hand, I have spent my lifetime trying to exercise hard all the time and have paid with repeated, persistent wear-and-tear injuries. Until recently, I just refused to take days off.

Last Saturday we raced 62 miles over a hilly course almost as fast as we could, holding back a little because we knew that we had to ride fast the next day also. On Sunday we raced 45 miles. On Monday, my legs were so sore that I took the day off. On Tuesday, my legs were still sore so we rode 20 slow miles. On Wednesday, my legs were still tired so we rode 43 miles, mostly easy with slight pickups when other riders came along. On Thursday, we rode 38 miles and on Friday, 46 miles. That amounts to 253 miles for the week with one day off. We are doing so many miles now that I try to stay off my feet when I'm not riding, because I know that walking and standing delay muscle recovery from hard exercise. We have several wonderful cycling trips planned this summer and will post some pictures soon.

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Football players more likely to become diabetic

People who have huge muscles usually have high levels of insulin because insulin causes muscles to grow. Exercise makes muscles so sensitive to insulin that it prevents blood sugar levels from rising too high. However, when these people stop exercising, their muscles are not as sensitive to insulin and blood sugar levels rise, this causes insulin levels to go even higher, so they eat more and gain weight.

A study from Mt. Sinai Medical Center shows that National Football League linemen are more than twice as likely as other Americans to develop diabetes in later life. More than 60 percent of NFL linemen become diabetic, compared to only 30 percent for the average American (The American Journal of Cardiology, May 2008).

People who have large muscles when they are young need to continue to exercise for the rest of their lives. If they reduce the amount of exercise or stop exercising for any reason, they must do everything in their power to protect themselves from gaining weight. Before insulin can do its job of driving insulin into cells, it must first attach to special insulin receptors on the surface of cells. Extra fat in the body prevents these receptors from responding to insulin, so blood sugar levels rise even higher. To compensate for this, insulin levels rise higher also, which sets the person up for diabetes and premature death.

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Caffeine Boosts Hot Weather Performance

A study from Toledo, Spain shows that giving caffeine to dehydrated bicycle racers helps them ride faster, longer and with more power in hot weather (Medicine and Science in Sports and Exercise, July 2008). When combined with water and carbohydrates, caffeine ingestion increases the force of muscular contractions which helps them to pedal with more power. Almost all professional bicycle riders take caffeine is some form because they know it helps them to ride faster.

Another recent study from the University of Illinois, Urbana-Champaign shows that caffeine helps to reduce muscle pain in riders pedaling as hard and as long as they can (International Journal of Sport Nutrition and Exercise Metabolism, May 2008). Other studies have shown that caffeine is a diuretic only when a person is at rest, not during exercise.

These reported benefits of caffeine for cyclists can be expected to apply to other sports as well. However, people with heart damage should be cautious about taking caffeine before exercising. It is a stimulant and may increase risk of irregular heart beats. More

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Causes and Treatment of Heatstroke

A recent report from South Africa shows that the most likely cause of death during hot weather sports events is heat stroke, when the body temperature rises so high that it cooks the brain (Medicine and Science in Sports and Exercise, July 2008). The treatment for a person who collapses from heat stroke is immediate immersion in cold water.

An excessive rise in body temperature is caused either by producing too much heat or by inability to dissipate the extra heat. When you exercise, almost 80 percent of the energy that is used to drive your muscles is lost as heat. That means that the harder you exercise, the more heat you produce. But heat stroke is more likely to be caused by inability to get rid of heat than by producing too much heat. Stimulants such as amphetamines, caffeine or ecstacy increase the likelihood of heatstroke.

Those most likely to suffer heat stroke are those who have arteriosclerosis, are overweight or are in poor shape. An athlete or exerciser who passes out from overheating should be immersed in cold water immediately to prevent brain and multiple organ damage. However, a heart attack can also cause a person to pass out and this should not be treated with cold water immersion.

If you exercise in the heat and start to feel dizzy, stop exercising because your temperature could be rising too high. When your temperature starts to rise, your muscles start to burn. As your temperature rises further, you become short of breath and the air you breathe feels like it is coming from a hot furnace. Stop exercising and cool off because if your temperature continues to rise, you will develop brain symptoms such as headache, blurred vision, and ringing in your ears. If you press on further, you can pass out and die. More

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Improving a Child's Running Form

When children look very awkward when they run, they usually have an imbalance in their muscles, or muscle or nerve damage. Telling an awkward child to change his form won't help and will probably just make him self-conscious. The child should first be evaluated by a physician for conditions that affect nerves and muscles. If none is found, the coach should have the child repeat the running motions over and over until the brain can coordinate the body's motions about his center of gravity. The faster he runs, the more likely he will be to acquire a running form that is efficient and does not waste energy with unnecessary side movements.

Your center of gravity is the spot in your body with equal weight in front and in back. Every motion you make is aimed at keeping your body balanced around your center of gravity. When you move one part of your body forward, you move another backward to keep you from falling. When you move your left leg forward, you automatically move your right arm forward and your left arm backward. People who don't do this look funny when they run. You can't talk a person into efficient running form and you cannot think yourself into good running form. To correct poor running form, go out and run every day and when you are in good shape, start running short interval sprints as fast as you can. How to run faster

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Changing Cancer Genes with Lifestyle

If you believe that cancer is genetic and there's nothing you can do to prevent it, take a look at the latest study from Dr. Dean Ornish. He reports that after just three months of a healthful diet and exercise, the genes associated with prostate cancer changed toward normal (Proceedings of the National Academy of Sciences, June 17, 2008).

The study involved 30 men with low-risk prostate cancer who had chosen not to undergo treatment unless their cancer got worse. The men followed a plant-based diet that avoided meat, saturated fat, and processed or refined foods; walked at least 30 minutes six days a week and at least an hour three days a week; and participated in a weekly support group. Each day they also did an hour of simple yoga-based techniques including stretching, breathing, meditation and imagery.

After just three months on Dr. Ornish's regimen, more than 500 genes associated with prostate cancer reverted toward normal. Cancer genes promote cell growth in a disorderly fashion. The researchers at University of California San Francisco (UCSF) showed that in these men, tumor-suppressing genes became more active and some of the cancer-causing genes switched off.

Many previous studies have shown that most cancers are caused by factors in the environment. Some people are genetically more susceptible to these factors. However, if they avoid the factors, they have an excellent chance of not suffering the cancers. We know that prostate cancer is more common in men who are overweight, diabetic, eat a lot of fat and meat, and/or do not exercise.

A leading theory is that each type of cancer is caused by many factors and the more of these susceptibility factors that involve you, the more likely you are to develop that specific cancer. For example, a woman cannot develop cervical cancer unless she is infected with the HPV virus. But more than 50 percent of American women are infected with this virus and fewer than one in 250 of those develop cervical cancer, so other factors must be involved. A woman with HPV who smokes has almost 20 times the chance of developing cervical cancer as one who has HPV and does not smoke. Other co-factors remain to be found.

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Tip for Hot-Weather Competitors

If you compete in a sport during hot weather, you may be helped by this tip for recovering between events.

Researchers at Edith Cowan University in Australia showed that you can recover faster and compete at a higher level by soaking your legs in cold water (14 degrees C) for five minutes during rest periods between events (British Journal of Sports Medicine, June 2008). The cooling session dropped body temperature a half degree centigrade and the athletes were able to cycle faster with greater power output.

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Vitamin D deficiency linked to many health problems

The hottest subject in medicine today is the amazing number of diseases associated with low vitamin D levels. People with low levels of vitamin D are at double the risk for blocked arteries in their legs, called peripheral artery disease (Arteriosclerosis, Thrombosis, and Vascular Biology, June 2008); markedly increased risk for heart attacks and strokes, angina, and heart failure (Circulation, January and April 2008; Archives of Internal Medicine, June 2008); increased rate of aging of their tissues (The American Journal of Clinical Nutrition, November 2007); cancers of the breast, lung and colon (American Journal of Clinical Nutrition, November 2007); diabetes (Epidemiology, May 20, 2008). Other recent articles show that Vitamin D helps pain control (Pain Medicine, April 2008); and vitamin D reduces the risk of falls (Archives of Internal Medicine, March 2008).

Next winter, ask your doctor to draw blood tests called vitamin D3 and D2. If your D3 level is below 40 ng/ml, you are at increased risk for a host of diseases. You can take pills containing D2 or D3. D2 is the plant pre-vitamin D that is so weak that it usually will not help raise your blood level. On the other hand, D3 is the animal pre-vitamin D that appears to be quite effective. Scientists do not agree on the optimum dose for people with blood levels of D3 below 40 ng/ml. It used to be 200 international units per day. Today, many doctors think that it should be at least 2000 international units. You can also meet your needs for vitamin D from sunlight by exposing a few inches of skin for 15 minutes every other day in the summer. However, during the winter in northern climates, the sun's rays come in at an angle and are therefore markedly reduced by the increased areas of atmosphere through which the sun's rays must pass. You can solve this problem with a tropical vacation.

I have found that tanning beds provide almost no vitamin D. Ultraviolet light is classified into UVA and UVB. UVB are the rays that cause skin cancer. They are also the rays that cause the skin to manufacture vitamin D. Since manufacturers of tanning bulbs are concerned about skin cancer, they reduce the percentage of UVB emitted from tanning lamps. This also markedly reduces the rays that provide vitamin D. More

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Hip Fat can be Hardest to Lose

I'm not overweight; how can I lose the fat in my hips and thighs?First, realize that people who are shaped like pears live longer than those who are shaped like apples (storing fat primarily in their bellies). "Pears" are less likely to develop diabetes, heart attacks, strokes, and many types of cancers. As you have already found out, diets are of not of much value to people who are generically programmed to store fat in their hips. For a diet to get rid of your hip fat, you would have to be hungry all the time. Exercise will work, but you may need to exercise more than three hours a day to get rid of hip fat. However, you might not have time for a job or your family.

Have you noticed that most female athletes have large buttocks? People who store fat in the buttocks are often genetically programmed to be gifted athletes. If you can double or triple your workout schedule, you would lose fat. Try competing in cycling, running or weightlifting. The odds are that you will be very successful.

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New Theory on Recovery from Workouts

The soreness that you feel 8 to 24 hours after an intense workout is caused by a tearing of the muscle fibers. The fastest way to get muscles to heal is to have your body produce lots of insulin and also provide a supply of protein to repair the damaged tissue. We have known for a long time that insulin drives sugar into cells for energy. Now we know that it also drives protein building blocks called amino acids into the muscle cells to help them heal faster. A study from New Zealand shows that protein loading immediately after exercise helps cyclists recover faster so they can ride harder for several days after an intense workout (Physiologie Appliquée, Nutrition et Métabolisme, February 2008).

On the surface of muscle cell membranes are little hooks called insulin receptors. Before insulin can do its job of driving sugar and protein into cells, it must first attach to these receptors. Hard exercise markedly increases insulin's ability to attach to insulin receptors and therefore makes insulin more effective. However, this increased response of insulin to exercise lasts only during exercise and for perhaps half an hour after exercise. An hour after you finish exercising, you have lost this added sensitivity of insulin receptors to insulin. So to help muscles recover faster, you need to take a carbohydrate source during a hard workout and immediately after you finish. Any source of carbohydrates will be broken down into simple sugars that call out insulin. Then, as soon as possible after your workout, you should eat any source of protein to supply the amino acids needed to heal damaged muscle tissue.

Entrepreneurs will probably use this information to promote various protein drinks and supplements, but you will get the same results with any sugared drink and any food or drink that contains protein. Soda and cheese or your favorite sports drink and shrimp or nuts will work just fine. More

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Low maximum heart rate signals fitness

No matter how hard I exercise, my heart rate never gets as high as my husband's. Should I be concerned? No; it may just mean that you are in very good shape. Researchers at Liverpool John Moores University in England showed that athletes have much lower maximum heart rates than sedentary people and that female athletes have lower maximum heart rates than male athletes (International Journal of Sports Medicine, February 2008).

Most exercisers should not even bother with heart rate calculations. Your training heart rate occurs when you exercise vigorously enough to make your body require more oxygen. You can tell when this happens because you will start to breathe deeper and faster, raising your shoulders with each breath. Once or twice a week, you should try to exercise intensely enough to increase your need for oxygen. If you feel uncomfortable, you should slow down. Non-athletes do not ever need to exercise so vigorously that they become severely short of breath. More

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Salt restriction hinders exercisers

Most doctors recommend low salt diets because of the evidence that taking in too much salt can cause high blood pressure, a major risk factor for heart attacks and strokes. However, this may not be good advice for dedicated exercisers. If you exercise heavily and restrict salt, you will not replace the salt you lose through sweating, which can cause high blood pressure as well as fatigue, cramps and muscle pain. When the body is low in salt, the adrenal glands produce large amounts of aldosterone and the kidneys produce renin, which constricts arteries and can raise blood pressure.

Researchers at Albert Einstein College of Medicine showed that people on low-salt diets are actually more likely to suffer heart attacks than those on high salt diets (Journal of General Internal Medicine, June 2008). They analyzed data from the Third National Health and Nutrition Examination Survey (NHANES III) of American adults. Dr. Hillel W. Cohen, lead author of the study, stated, "Our findings suggest that for the general adult population, higher sodium is very unlikely to be independently associated with higher risk of death from heart attacks."

Many years ago, when I was competing in marathon races, I decided to try a low-salt diet. I was surprised to find that my blood pressure rose from a normal 120/ 80 to as high as 160/80, and I suffered severe fatigue and frequent injuries. When I added salt back into my diet, my blood pressure went down to normal and I was able to train and compete again. This is why I recommend a relatively high-salt diet for exercisers. If you decide to increase your intake of salt, get a blood pressure cuff and check yourself for a month. If your blood pressure goes above 120/80, you may have added too much salt. Also, if you stop exercising because of an injury or for any other reason, be sure to cut out the extra salt to keep your blood pressure under control. More

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Fewer Omega-6's May Reduce Cancer Risk

Researchers at UCLA show that reducing intake of corn oils helps to prevent prostate cancer in mice (Cancer Research, April 15, 2008). Corn oil and other vegetable oils are extremely rich sources of omega-6 fatty acids.

Fats are classified by their chemical structure into omega-3s, omega-6s, and omega-9s. Omega-6s cause your body to produce prostaglandins that turn on your immunity to cause inflammation, while omega-3s turn down your immunity to reduce inflammation.

Your immunity is supposed to be good for you. When a germ enters your body, your immunity produces white blood cells and proteins called antibodies that attack and kill the germ. After that germ is gone, your immunity is supposed to stop making so many immune cells and proteins. If it remains active, your immunity attacks your own body to damage tissue and increase risk for heart attacks, certain cancers, and diabetes; it can also worsen existing diseases such as some types of dementia, asthma or psoriasis.

For more than 2 million years, humans have eaten diets that have a ratio of omega-6s to omega-3s of about two to one. However, over the last 100 years, humans have added extracted vegetable oils to other foods that they eat and increased the ratio to 12 to one and perhaps as high as 20 to one. This increase in the ratio of omega-6s to omega-3s is a cause of inflammation. The increase in omega-6's has come primarily from vegetable oils that are added to baked, fried and other prepared foods. Omega-3s oils are relatively unstable so they are not found in most prepared foods.

Good food sources of omega-3's include seafood and beans, whole grains, nuts and other seeds. We do not know if changing the ratio of omega-6s to omega-3s will help to prevent cancers in humans, but several studies show that they appear to both prevent and slow cancers in animals.
More on omega-3s and omega-6s

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Breast Cancer Risk Lower with Exercise

A recent study from Washington University School of Medicine in St. Louis shows that exercise starting during adolescence can protect girls from breast cancer (Journal of the National Cancer Institute, May 2008). Researchers tracked 65,000 nurses who answered questionnaires about exercise. Within six years, 550 were diagnosed with breast cancer before menopause. Those who exercised regularly as teens were 23 percent less likely to develop premenopausal breast cancer than their sedentary peers. Ages 12 to 22 appear to be the most important time to use exercise to help prevent breast cancer.

Higher estrogen levels increase risk of breast cancer. Exercise lowers estrogen by reducing body fat. Fat cells make estrogen, and after the menopause fat cells are the principal source of estrogen. Other factors that increase breast cancer risk are also related to higher estrogen levels: starting to menstruate at an early age, late onset of menopause, taking estrogen after menopause, and being overweight.

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Kidney function improved by exercise

We already know that exercise helps to prevent heart attacks, strokes, diabetes, obesity and certain cancers, and may extend life span. Now a report from Italy shows that exercise may also help to prevent kidney damage that occurs with aging (Clinical Journal of Sport Medicine, May 2008).

Doctors measure kidney function by calculating the ability of the kidneys to rid the body of a breakdown product of metabolism called creatinine. Regular exercisers have lower blood creatinine levels and also have kidneys that are better able to clear creatinine from the bloodstream as measured by a test called Glomerular Filtration Rate (GFR).

According to this study, professional bicycle racers have better kidney function than both sedentary people and recreational cyclists. This is very interesting because professional cyclists dehydrate themselves with almost every workout, in spite of the huge amount of fluid they consume. The researchers found that frequent dehydration accompanied by drinking large amounts of water did not cause kidney damage. This repeated stress on the kidneys may even explain why the professional cyclists had better kidney function than the less-active participants.
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Ibuprofen reduces risk of Alzheimer's

Researchers at Boston University School of Medicine followed 250,000 veterans over the age of 55 years and showed that taking ibuprofen for five years was associated with a 40 percent reduction in the development of Alzheimer's disease (Neurology, May 2008).

Alzheimer's disease is associated with the deposition of tangled webs of protein in the brain. Several previous studies show that ibuprofen reduces these protein deposits in the brains of animals. A leading theory on the cause of Alzheimer's disease is that a person's immunity attacks the brain to cause dementia. Ibuprofin reduces inflammation, the body's response to an overactive immunity. Another study in the same issue of Neurology showed people that with shorter arms and legs may be at a higher risk for developing dementia later in life. More on preventing dementia

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Smoking Bans DO Reduce Teen Smoking

Teenagers who live in cities or towns with strict smoking bans are 40 percent less likely to become regular smokers, according to a study published in the Archives of Pediatrics & Adolescent Medicine (May 2008). The study also reported that youths with smoking parents or friends are at high risk for smoking themselves, but strong smoking bans in restaurants reduce the chance that they will become smokers.

Massachusetts passed a workplace smoking ban that included restaurants in 2004. Since then, high school smoking rates in Massachusetts have dropped from 21percent of students in 2005 to 18 percent in 2007. At least 23 states, the District of Columbia and Puerto Rico now require most public places and workplaces, including restaurants and bars, to be smoke free.
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Progesterone helps to prevent uterine cancer

They're supposed to prevent pregnancy, and they do, but intrauterine devices (IUDs) also reduce uterine cancer risk by more than 40 percent (Meeting of the American College of Obstetricians and Gynecologists, May 6, 2008).

An IUD is a small, T-shaped plastic device inserted into the uterus. Only two percent of women who use contraception in the United States choose an IUD, despite the proven safety and effectiveness of this long-term method. Worldwide, however, IUDs are the most widely used reversible contraceptive. Most IUD's prevent pregnancy by releasing small amounts of the hormone progesterone into the uterus. This is also why they help to prevent uterine cancer.

The ovaries of healthy women are supposed to produce two hormones: estrogen and progesterone. Many women lack progesterone and they are the women who are at increased risk for uterine cancer. Estrogen stimulates the uterus to grow, and progesterone stops the stimulation. If a woman has estrogen and no progesterone, her uterus is stimulated all the time, which can lead to uncontrolled growth which is cancer.

The woman most likely to get uterine cancer has high blood levels of insulin. Insulin acts directly on the ovaries to stop them from releasing eggs. Women who do not release eggs have no progesterone and therefore are at high risk for uterine cancer. A woman can find out if she has high insulin levels just by getting a blood test, called C peptide, that measures insulin production by the body. If it is above 3, her body makes too much insulin.

However, you can usually tell if a woman has too much insulin just by looking at her. Insulin causes a person to lay down fat primarily in the belly. Women with big bellies and small hips usually have high insulin levels and are also at high risk for diabetes. Most people who will develop diabetes usually stop responding to insulin. This causes the pancreas to release increasing amounts of insulin, until the pancreas eventually dies and then the person must take insulin.

If you are a woman who stores fat primarily in your belly, you should get blood tests called C peptideand HBA1C to see if you are already diabetic. You can also tell if you are pre-diabetic if your good HDL cholesterol is low, your triglycerides are high, or your liver shows excessive amounts of fat. Start a supervised exercise program, lose weight, and restrict refined carbohydrates. You may also want to see if your doctor advises using an IUD to help prevent uterine cancer.
More on Polycystic Ovary Syndrome (PCOS)

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How Vitamin Pills May Affect Lifespan

The issue of vitamin supplements is far from settled. Most doctors take multivitamins themselves and recommend them to their patients. However, I continue to believe that it is better to get vitamins in whole foods than in pills.

Most vitamins are parts of enzymes that start chemical reactions in your body. Each chemical reaction produces end products that are changed by further chemical reactions from other vitamins to other products that benefit your body. When you take a vitamin that has been isolated from the hundreds of other substances found in foods, that enzyme causes a chemical reaction that accumulates a disproportionate amount of its end products. If the substance that acts as an enzyme for the next chain of chemical reactions is not available, you can accumulate end products that may be harmful.

For example, people who take niacin to lower cholesterol show a marked elevation of homocysteine, a major risk factor for heart attacks. Homocysteine levels are raised by a deficiency of B12, folic acid and pyridoxine. When you eat your niacin in whole grains, all of those components are present, along with many others whose functions we may not yet understand.

The study I mentioned in the previous post is in Cochrane Database of Systematic Reviews More

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Prevent Injuries: Background Before Peaking

Injuries often occur when people start a new exercise program, change to a different sport, or return to exercise after a long break. In the enthusiasm to get started, it is easy to overstress muscles that have not been used before. That's why "background before peaking" is one of the most important principles of training. It takes several weeks or even months to build up strength and endurance for any new sport.

Competitive athletes in all sports use this principle. First they spend many months in background training, working out for long hours, mostly at low intensity, followed by a shorter period of peak training in which they do far less work, but at a much greater intensity. A few months before an important race, they reduce their workload but go as fast and hard as possible two or three times a week.

Start your new exercise program at very low intensity and low volume. Gradually increase your workload for several months before you try to run fast, lift heavy or exercise intensely. If you are just beginning to exercise, go at a relaxed pace until your muscles feel heavy and then stop. For the first several days or weeks you may be able to exercise only for a few minutes at a time. If your muscles feel sore the next day, take the day off. Increase the amount of time gradually until you can exercise 30 minutes a day at a relaxed pace and not feel sore. You may progress rapidly to the 30-minute goal, or it may take you two, four, six weeks or more. No matter how long it takes, don't get discouraged. Exercising too much or too hard, too soon will set you up for injuries. More

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Weight Lifting Past Fatigue Does Not Strengthen Muscles More

When you want to become very strong, you try to lift very heavy weights. Weight lifters have known for a long time that you don't pick up the heaviest weight you can move, raise it once and then quit for the day. They do their weightlifting in sets. For example, they lift and lower a weight in three sets of ten or one set of six.

If you exhaust your muscles by bench pressing a weight for three sets of ten, is there any benefit to try to do another set? Researchers from Australia showed that you gain nothing if you force extra lifts after your muscles are exhausted (Journal of Strength and Conditioning Research, August 2007). This study should serve as a warning particularly to young lifters. Plan your workouts. When your muscles are tired or sore, don't try to keep on lifting through the soreness. After a hard workout, go easy for as many days as it takes for your muscles to feel fresh again. More

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Get Your Vitamins From Food, Not Pills

One in three women and one in four men in the United States take vitamin pills. If you are among them, you may be doing more harm than good. In a wake up call to the multibillion dollar vitamin pill industry, a review of 67 randomized trials of vitamin pill effects on life and health has found that taking vitamin pills may shorten life (Cochrane Database of Systematic Reviews, Issue 1, 2008). Other studies have shown that taking vitamin pills may increase risk for cancers and heart attacks.

This review of 232,000 adults showed that those taking beta-carotene, vitamin A, C, and E and selenium gained no benefit over those who took placebos or no pills. "The findings show that, if anything, people in trial groups given beta-carotene, vitamin A and vitamin E showed increased rates of mortality. There was no indication that vitamin C and selenium may have positive or negative effects."

The study was originally set up to see if antioxidant vitamin pills and minerals prevent gastrointestinal cancers. It found no protection whatever. Instead, an increased death rate of 16 percent was seen in those taking vitamin A pills, seven percent with beta- carotene, and seven percent with vitamin E. No increased death rate was seen in those taking vitamin C or selenium. Free newsletter

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Will Organic Foods Make You More Healthy?

According to a report published by The Organic Center's State of Science Reviews(March 2008), organic foods are more nutritious than those grown conventionally. But since the average North American eats far more food than is necessary, it is doubtful that adding more nutrients to the diet will have much effect on health.

A review of 97 scientific papers shows that organic food has higher levels of eight of 11 nutrients studied, including greater concentrations of polyphenols and antioxidants. However, we don't know how much of these nutrients the body requires. With 35 percent of the population becoming diabetic, 91 percent developing high blood pressure, 78 percent having high cholesterol levels, and 40 percent dying of heart attacks and strokes, I think it is more important to focus on the lifestyle factors that cause these health problems: overeating; eating too much meat, saturated fat, partially hydrogenated fats and refined carbohydrates; not eating enough vegetables; exercising too little; drinking too much; and smoking. Enjoy organic products if they fit into your budget, but you harm yourself if the higher cost causes you to eat fewer fruits and vegetables.

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How Exercise Prevents Diabetes AND Preserves Your Brain

Several studies show that vigorous exercise can help to prevent and to treat diabetes. A recent study from the University of Missouri in Columbia helps to explain why (American Journal of Physiology - Regulatory, Integrative and Comparative Physiology, April 2008).

The vast majority of people who have diabetes do not lack insulin. Their disease is caused by an inability to respond to insulin. Since their cells do not respond to insulin, blood sugar levels rise and damage their cells. By studying blood flowing to and from the hind legs of obese rats, researchers found that acute muscle contractions markedly increased the passage of sugar into skeletal muscles, and markedly increased the flow of electrons in mitochondria.

Muscle cells have anywhere from six to thousands of tiny inclusions called mitochondria. Mitochondria convert food to energy by shuffling electrons from the building blocks of food. Each movement of electrons supplies more energy. However, in converting food to energy, some electrons end up attached to oxygen to produce reactive oxygen species (ROS) that stick to your DNA and proteins to damage them, preventing insulin from doing its job of driving sugar into cells and shortening cell life. When a muscle contracts, it shunts electrons away from oxygen so that fewer reactive oxygen species are formed.

Furthermore, this same process protects brain function and helps to prevent strokes, Alzheimer's and Parkinson's diseases. A study from Semmelweis University in Budapest shows that the lowering of ROS levels with exercise helps to prevent loss of mental function (Applied Physiology, Nutrition and Metabolism, October 2007).

More than 80 percent of diabetics die of heart disease. If you are at high risk for diabetes or are already diabetic, check with your doctor and perhaps get a thallium stress test to check out the condition of your heart. If you pass the test, you should try to exercise as much as possible. More on insulin resistance

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Vitamin C Won't Help You Exercise Longer

Some exercisers take vitamin C because they think that it will help them recover faster and therefore become better athletes. However, a study from the University of Valencia in Spain shows that vitamin C pills can make an athlete tire earlier during long-term exercise. (Journal reference)

Every muscle cell has hundreds, and even thousands, of small inclusions called mitochondria that turn food into the force that drives muscles. They do this by shuffling electrons to produce energy. After the electrons are moved, they can end up stuck on oxygen molecules to produce poisons called oxidants that make muscles burn, and feel sore and tired. The human body produces antioxidants that help protect a person from cell damage from these oxidants. Large doses of vitamin C have been shown to block antioxidants, so giving large doses of vitamin C to either humans and animals before they exercise would make them tire earlier.

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Microwaving Does Not Harm Foods

A report from the nutrition department of Cornell University should convince you that microwaving food does not destroy its nutritional value. Dr. Gertrude Armbruster and her colleagues showed that fruits and vegetables lost the least vitamin C when microwaved, compared to other cooking methods. Vitamin C is a good indicator of the amount of nutrients lost because it is both water soluble and sensitive to heat (Newsweek, March 14, 2008).

Microwave ovens use electromagnetic waves that vibrate water molecules inside food to produce heat. Most nutrients in food are not destroyed by microwaving because they are not in the watery layer. An earlier study from Spain, widely reported in the news media, claimed that microwaving broccoli destroyed all of its antioxidants (Journal of Science in Food and Agriculture, November 2003). However, the researchers in this study cooked the broccoli in almost a cup of water for five minutes at full power. The antioxidants were destroyed by the long cooking in water at a high temperature, not by the microwaves. The length of time vegetables are exposed to hot water determines the amount of water-soluble nutrients lost, whether the cooking is done in a microwave oven, steamer, pot or pressure cooker. For nutrient- rich vegetables from your microwave, use very little water (no more than a tablespoon or two) and short cooking times.

Contrary to myths spread by a popular natural health newsletter, the radiation from microwaves is not harmful and has no effect whatever on food other than to heat it up. Once the food comes out of the oven, there are no lingering effects of the microwaves. If you are worried about chemical changes to the nutrients in your food, avoid broiling, grilling, frying or any other method that browns foods. The reason food cooked in a microwave oven is so bland is that the chemical changes caused by high surface temperatures don't happen. That's why most people use their microwave ovens to reheat food instead of for cooking. More

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Vitamin D and Muslce Pain - Special Report

Over the last few years I have reported on numerous studies linking vitamin D deficiency with various diseases: diabetes, heart attacks, at least 30 types of cancer, and autoimmune disease such as lupus and rheumatoid arthritis (a list of these reports appears below).

This winter I have had a series of baffling exercise- associated muscle injuries. My blood levels of vitamin D have been extremely low, even though I spend a lot of time outside riding my bike. I reviewed my diaries and found that wintertime injuries have been a lifelong pattern for me. I have not been able to find any strong evidence that lack of vitamin D causes muscle injuries. However, it is associated with muscle weakness, falling in older people, bone deformities and fractures.

People get most of their vitamin D from sunlight. The skin has an enormous capacity for vitamin D production and supplies the body with 80-100 percent of its vitamin D. However, a recent study showed that a high percentage of people in sunny Arizona are vitamin D deficient (American Journal of Clinical Nutrition, March 2008). How can this be? A clue to the problem is that a large percentage of the people who were deficient were African- American, Hispanic, elderly or overweight. We know that people who have dark skin need more vitamin D because dark skin blocks the sun's UVB rays that make vitamin D. Another study showed that almost 50 percent of African Americans in Boston had low vitamin D in March. We also know that obesity can cause vitamin D deficiency because body fat removes vitamin D from circulation. Furthermore, as people age, skin cannot synthesize vitamin D as efficiently and the kidneys are less able to convert vitamin D to its active hormone form.

An article from Australia showed that 15 out of 18 gymnasts in Australia suffered from vitamin D deficiency (Clinical Journal of Sport Medicine, March 2008). These athletes spend a lot of time training indoors. Even if you spend several hours a day outside in winter, you probably will not get enough sun to meet your vitamin D needs. At our latitude the sun's rays reach earth at an angle so they have to penetrate a thick layer of the earth's atmosphere and fewer rays get through. Also, when the weather is cold we cover most of our skin with clothing.

My personal plan and recommendations

While we wait for the scientific community to resolve whether lack of vitamin D causes cancers, heart attacks and so forth, or is just a marker for other risk factors such as lack of activity or excess weight, I think you should be aware of your own vitamin D status and take action if you are deficient.

If you seldom go outdoors, have dark skin, are over 50 or are overweight, I recommend that you ask your doctor to do blood tests for vitamin D3 and D2. D3 is made by your skin from ultraviolet light (UVB) or from the vitamin D you get in foods or supplements. D2 comes just from food or supplements. Your total blood level of vitamin D should be over 50. If it is below 50, you may need to take a tropical vacation, use a tanning bed or take vitamin D supplements. A safe dose appears to be 1000 IU per day during the winter.

Until summer arrives and my vitamin D levels return to normal, I have chosen to use a tanning salon. I am reluctant to take supplements because one study from Australia suggests that they may suppress the body's ability to synthesize vitamin D.

Tanning lamps emit both UVA and UVB. However, because UVB are the primary rays that cause skin cancer, most tanning beds are high in UVA which does not make vitamin D and low in UVB that makes vitamin D. Ask the tanning center about the amount of UVB in their lamps. Some have 70 percent UVA and 30 percent UVB, but some emit less than five percent UVB. If you use a tanning bed, start at very low exposure, preferably with less than five minutes on your first visit. You won't know if you have burnt yourself until that evening. Then add only two minutes per exposure and don't go every day. After a couple of weeks, you can repeat your blood test. Stop using tanning bed when your total level reaches 50. If it does not reach 50 in a month, you should stop the tanning bed and take vitamin D supplements.

I will report to you from time to time on the progress of my training program, injuries and vitamin D levels; and I will continue to survey the scientific literature for studies on the association between vitamin D and various health problems. My earlier reports on vitamin D

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