The FDA, acting on a recommendation to be made by a task force of the Institute of Medicine of the National Academy of Sciences, is about to take the unprecedented step of regulating the salt content of processed foods. There actually is a scientific rationale for this. Numerous studies have shown that high sodium chloride (salt) intake is associated with an increased likelihood of hypertension leading to strokes, heart attacks, and congestive heart failure. Of course tobacco isn’t good for you either, but the FDA, which now regulates cigarettes, isn’t talking about reducing the nicotine levels in every pack of cigarettes sold in the United States. The question is, why salt? How dangerous is it?

The risk has mostly been based on the results of so called “observational studies,” where patients are not asked to ingest a given amount of salt but rather are assessed based on their own preferences. In these studies, the effect of dietary salt level on blood pressure is determined. The results generally show that a high salt intake leads to a higher risk of heart and vascular disease because blood pressure is higher with a high salt diet. But you have to take those numbers with a grain of salt. No one has really proven that a low salt diet will reduce heart disease, only that it will lower blood pressure. While it is true that it is likely that higher blood pressure will lead to more heart disease, the proof that removing salt from processed food will improve survival could represent the triumph of hope over reality. Also, high cholesterol levels, untreated hypertension, diabetes, and smoking convey a far higher risk of heart and vascular disease than does a high salt intake.