President's address: salt-too much of a good thing?
Year: 2007
Type: other
Abstract: The important role of salt in recent human history is evident in the many phrases that have become part of our language. An example is “worth his salt”, that is worth his salary, which is derived from the Roman word for salt as pay especially for soldiers in Roman times. “Sitting above the salt” refers to the place of aristocracy above the common folk. Other examples are old salt for a sailor, putting salt in the wound, and Attic salt for a sharp wit. The French welcome Salut is also derived from salt. Over the few thousand years of recorded history, salt has been used as a symbol for purity, in religious ceremonies, as currency, preservation of food, and treatment of wounds. It has been of major military significance, providing adequate food stores for armies on the march. Several nations, including France, Ancient China and British India, had state monopolies of salt and used it as a vital source of tax monies. Much of this is detailed in a fascinating book by Mark Korlanski entitled, Salt a World History (1).
My goal is to persuade you that our present high intake of salt is harmful for the health of Western industrialized societies, and that government regulation is justified to reduce concentrations of salt in processed foods which constitute an increasing proportion of our caloric and salt intake. Indeed, most of us obtain 80% of our salt intake from processed food (2). The units used to measure the salt or sodium content of food in labeling and in the popular press can be quite confusing. I propose to use measurements as grams(g) of salt (sodium chloride); the relationships between sodium and sodium chloride in mEq and mg is shown in Table 1.
TABLE 1
Salt: Units of Measurement
The Paleolithic (or Stone) Age lasted from approximately two and a half million years to around 10 thousand years B.C. During that time, the bipedal animals (hominids) that proceeded Homo sapiens, which emerged about 40,000 B.C., consumed a diet consisting mainly of fruit and vegetables and wild game (2,3,4). This hunter-gatherer diet continued for approximately 100,000 generations, during which time, salt intake was much lower than it is today, at 0.5g salt if mainly vegetarian and 1.6g salt if also carnivorous (3). Today's average daily intake in the Western World is considerably higher at around 10g salt. Our present species developed agriculture about 10,000 B.C.—that is approximately 300 generations ago from the evolutionary viewpoint. At that time, considerable changes occurred with the development of cultivated crops. The industrial age again changed our diet over a span of 5–10 generations till now. The growth of processed foods with national distribution mechanisms only really began after World War II, two generations ago. We thus live with the genes of the hunter/gatherer diet. These “thrifty genes” (5) were selected over a long period, during which our ancestors had to deal with low salt intake, periods of starvation and caloric inadequacy, favoring development of thrifty genes controlling renal mechanisms that are sodium acquisitive. The hunter/gatherer diet was much higher in potassium and likely calcium and magnesium than that of the present day, and contained carbohydrates with a lower glycemic index and fewer saturated fats (2,3). The diseases of civilization like hypertension, diabetes mellitus, the metabolic syndrome, obesity and atherosclerotic disease, in general, affect us in later life and thus do not prevent reproductive passage of these genes to the next generation.
Source: PubMed
Author: Robert G Luke
Language: English
Topic: Sodium Intake and Health
Subfield: Nutrition and Dietetics
Field: Nursing
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W272696741