Who should restrict salt? (and who should not?)

Most doctors recommend salt restriction for all their patients, even though many will not develop high blood pressure from high-salt intake and some may even be harmed if they restrict salt. Heavy exercisers lose so much salt that they have to take in lots of salt just to replace what they lose through sweat.

A study from China shows that people with metabolic syndrome are the ones who are most likely to develop high blood pressure from a high-salt diet and that high levels of insulin may cause the rise of blood pressure that is associated with increased salt intake (Lancet, published online March 2, 2009). Metabolic syndrome occurs when a person's cells lose their ability to respond adequately to insulin and blood levels of sugar rise too high. It is caused by eating too much refined carbohydrates, being overweight, not exercising, and lacking vitamin D and is characterized by storing fat primarily in the belly, having a thick neck, high blood triglycerides, low blood good HDL cholesterol, high blood sugar, and eventually liver damage and all the side effects of diabetes. People with metabolic syndrome had a greater rise in blood pressure with increased salt intake and drop in blood pressure with salt restriction. The more risk factors for metabolic syndrome a person had, the greater the rise and fall of blood pressure with changes in salt intake.

If you are concerned about your blood pressure, you can buy an inexpensive wrist cuff and check your blood pressure at bedtime. If it is below 120, you do not need to restrict salt. If you store fat primarily in your belly rather than your hips, your HDL is below 40, your triglycerides are above 175, or you have a blood sugar above 100 two hours after a meal or an HBA1C above 5.9, you probably should restrict salt and definitely should work to correct the causes of metabolic syndrome (described above).