Human beings are believed to be programmed to eat and metabolize both plant and animal foods. It is believed that the genetic program, which has remained essentially unchanged for at least the past 100000 years, is best compatible with unprocessed mixed foods. According to this hypothesis, marked man-made changes in the composition of foods and diets would cause, or at least predispose to, a number of pathologic conditions, including elevated blood pressure.
The sodium content of a daily diet, composed of ingredients not artificially enriched by salt, ranges between 0,23g and 0,8g. It is almost impossible to compose a diet consisting of unprocessed natural foodstuffs to provide sodium in excess of 1.2 g a day. Therefore, on the basis of the variation of sodium content in diets consisting of natural foodstuffs without artificial additions, one could expect that our genetic mechanisms are programmed to sodium intake levels that are lower than 1.2 g a day.
Blood pressure serves 2 important functions in the body. One is maintenance of tissue perfusion. The other important and extremely potent function is control of sodium balance, which largely determines the extracellular fluid volume. By increasing the blood pressure level, the body is able to get rid of excess sodium and water. This explains how the high sodium diets can have the effect of increased blood pressure.