A Better Reason to Reduce Salt

Just when it looked like we could relax about the amount of salt we use, it seems that we may need to limit how much of it we use after all.

I used to trust the recommendations of the American medical establishment that we must reduce the amount of salt we use in order to control hypertension (high blood pressure). Early last year, in fact, I wrote here how we can reduce it to help control our blood pressure.

But in “The (Political) Science of Salt” iconoclastic science writer Gary Taubes exposed the myth that if you, “Eat less salt…you will lower your blood pressure and live a longer, healthier life.” Many of us with diabetes believed this myth — with the prodding of our doctors — because high blood pressure goes hand in hand with diabetes. High blood pressure — hypertension — and diabetes are two of the main components of the so-called “metabolic syndrome” or “syndrome x.”

By whatever name, the reason to care about this syndrome is that it is a collection of risk factors that increase our risk of developing heart disease. Since diabetes is one of those risk factors, we need to do everything we can to avoid collecting more of them.

And now it appears that too much salt harms our heart in another way. Scientists at Scotland’s University of Dundee gave a heavy load of salt for just a couple of weeks to a small group of 16 young men with normal blood pressure in a randomized, double-blood trial.

The study, “Adverse Cardiovascular Effects of Acute Salt Loading in Young Normotensive Individuals,” came out in the June 2008 issue of Hypertension, which the American Heart Association publishes. The lead author, Dr. Nikolaos Tzemos of Dundee’s Hypertension Research Centre, sent me the full-text of the study, since only the abstract is free online.

In addition the salt load impaired their left ventricular relaxation and increased QT dispersion. The QT interval measures the time between the start of the Q wave and the end of the in T wave our heart’s electrical cycle. In other words, salt caused increase stiffness in the lining of their arteries and in the main pumping chamber of their hearts.

The study concluded that too much salt in our diet may have a “substantial” adverse effect. We need larger and longer studies to confirm this newly discovered problem with salt. Meanwhile, prudence seems to call for us to limit the amount we eat, even if we don’t have a concern with salt’s effect on our blood pressure.

This article is based on an earlier version of my article published by HealthCentral.