In popular thought, disputing sodium's link to high blood pressure is equivalent to questioning whether the earth is round. However, some experts now believe that salt will not raise blood pressure in everyone, just in people who are "salt sensitive." Only 10 percent of the population is salt sensitive, according to BioMarkers by Professor William Evans and Dr. Irwin H. Rosenberg.

Of course, far more than 10 percent of us suffer from hypertension, meaning that if these experts are correct, salt intake cannot be the only factor contributing to America's high blood pressure epidemic. In fact, according to Gayle Reichler's book, Active Wellness, only half the people with hypertension have high blood pressure because of their salt intake, making cutting down on the amount of salt you eat a good step toward lower blood pressure, but not a cure-all.

Scientists are still unsure why some people's bodies respond to salt more drastically than others; however, most theories focus on sodium's in vivo interaction with potassium, magnesium and calcium. In fact, some experts believe that these nutrients play more of a role in these individuals' salt sensitivity than sodium itself. Deficiencies in these complementary minerals may actually be the larger culprit in hypertension.

"The problem is just as likely to be too little potassium, calcium and magnesium," emphasizes Alice Feinstein in Healing with Vitamins. Most experts agree that you would do well to consume sodium in balance with potassium in order to maintain healthy blood pressure, but they are still unsure about how this potassium mechanism works. Some experts believe that potassium lowers blood pressure by relaxing small blood vessels, while others think that it works by helping the body expel excess sodium and water.

Another interesting theory asserts that these people actually have hypertension because of calcium deficiency, rather than an excess of sodium. However, as Jean Carper explains in Food: Your Miracle Medicine, proponents of this theory have multiple theories about how it might operate: "One theory is that such individuals retain water when they eat too much sodium, and that calcium acts like a natural diuretic to help kidneys release sodium and water, thus reducing blood pressure. Another, more complex explanation is that calcium works by preventing release of the parathyroid hormone that can raise blood pressure."

As is often the case with uncharted health territory, when it comes to the salt sensitivity explanation for hypertension, theories often pile upon theories. This isn't a bad thing; rather, it makes the intellectual environment ripe for new discoveries. On the other hand, it's important to remember that not all experts agree with the salt-sensitivity theory. "There's no question about it: A great number of comparative studies of people who use no salt and those who use great quantities have proved that high salt equals high blood pressure," writes Gary Null in his Complete Guide to Health and Nutrition.

Dr. William Castelli, director of the famous Framingham Heart Study, also cites demographic studies as support for the mainstream medical viewpoint that consuming excess sodium leads to hypertension, a perspective that some naturopaths also share. Furthermore, in Food Politics, Marion Nestle questions the ethical roots of some of the salt-sensitivity theory's proponents, pointing out some objectionable financial backing: "'There is reason to be concerned that lowering NaCl [salt] intake may have long-term metabolic risks that have not been fully identified . . . we do not have solid evidence that lower NaCl intake prospectively will prevent or control high blood pressure."

However, the review in which this appears was funded in part by The Salt Institute, a trade association for the salt industry. This isn't to say that all experts who believe in salt sensitivity are funded by the salt industry. Like any theory, the salt sensitivity explanation for why some people have high blood pressure and others don't has both its proponents and opponents.

A simple test to determine if you are low in the enzyme renin will show you whether you are salt sensitive, according to Reichler. Of course, an even simpler way is to cut down on your sodium intake for a few months – under the care of a doctor, or preferably a naturopath – and see if your blood pressure goes down. If your numbers go down, then you are salt sensitive; if not, you and your naturopath must then take extra steps to learn the cause of your hypertension.

The point is, as Dr. Bernard Lamport emphasizes in Food: Your Miracle Medicine, "Everyone cannot count on sodium restriction to be a panacea for high blood pressure." In other words, as we all know, obtaining good health requires taking a holistic approach to your body, not just making one change and hoping that it will be a cure-all.