How much sodium are you consuming? The answer will shock you.
by Robert D. Lucas, Ph.D.
Recently, on prime time Caribbean Broadcasting Television (CBC –TV News at 7pm); a public notice about the adverse effects of salt in the human diet has been given extensive coverage. The gist of the message disseminated, was the need for a reduction in the consumption of salt in the diet. This is a very laudable effort on the part of the authorities, to educate the consuming public. I will now give a critical review of the notice, as-well-as indicating the function of common salt in the human diet and in processed foods. This is of some use, since there is a high incidence of hypertension and diabetes locally.
Before I start on the above mentioned exercise, it is necessary to indicate that, there are many salts used in the food industry. The salt referred to in the notice was common salt or sodium chloride (NaCl). This is the compound normally referred by lay people in alluding to the salt content of foods. Sodium Chloride consists of one atom of sodium and one of chlorine. The sodium component of common salt is responsible for imparting flavor in foods. Gillette. 1985. “ Flavor Effects of Sodium Chloride.” Food Technology. 39:6: 47-52.). It is also responsible for the adverse health effects in humans, when consumed in excess. “The physiological role of sodium is to provide the proper osmotic balance in the extra cellular fluids of the body.” (Sebranek and others. 1983. “Physiological role of Dietary Sodium in Human Health and implications of Sodium reduction in Muscle Foods.” Food Technology. 37: 7:51-59).
The effect of sodium on the extra cellular fluid volume (ECFV) has led to its implication as a causal factor in hypertension. A look at the nutritional facts section of the label on processed foods reveals that only the Na (sodium) part of common salt is listed. It is therefore, misleading to allude to the necessity of reducing the salt content of foods. Emphasis should be on the reduction of sodium(Na) in the diet.
Since the 1970’s, the sodium(Na) content of restaurant and processed foods in America have increased. Americans now consume 3,400 milligrams(mg) of sodium (Na) every day exceeding the daily recommended allowance of 2,300 mg/day (Tarver, T. 2010. “Desalting the Food Grid.” Food Technology. 64:8: 45-50). It should be noted that, the nutritional facts sections of processed foods, indicate that the latter normally, contain more than seventy percent of the daily requirement of sodium [Na] ( Tarver, T. 2010).
Most foods consumed by humans contain sodium. For example, hams contain sodium derived from the following compounds (salts): sodium nitrite, sodium tri-poly phosphate and sodium chloride (common salt). The consumer is therefore faced, with the cumulative effective of sodium (Na) from these three sources. In fruit juices, sodium (Na) is found in the form of either sodium benzoate or sodium meta-bisulfate. In baked goods such as bread, sodium is found in the form of sodium bicarbonate or baking powder. In some foods, the nutritional facts may also report be as sodium ( Na) and as its equivalent in terms of sodium chloride. For example, in baked beans 0.3g of sodium(Na) per 100g is also expressed as the equivalent of 0.9 g of sodium chloride. This is normally the case for foods from the European Union.
The human body needs modest amounts of sodium (Na) to facilitate absorption of nutrients and the proper functioning of cells. In the food-processing industry, sodium enhances the flavor of processed foods, masks bitter and acidic tastes and increases the sweetness of sugar. In addition, it has preservatives properties.“Unfortunately, a significant reduction of sodium content in virtually any food item, results in a concurrent reduction in flavor and hence consumer acceptance.”(Gillette. 1985). To counter act this trend, flavor enhancers can be used. These include mono-sodium glutamate (MSG), autolyzed yeast extracts, hudrolyzed vegetable protein and soy sauce. All of these compounds contain glutamate. When MSG is added to foods, since it also contains sodium (Na), it is necessary to reduce the amount of common salt (NaCl) added. Use is made of what in physical chemistry is known as the common ion effect; that is, the effect of the sodium in MSG on the sodium of common salt. When flavor enhancers are used, the amount of sodium chloride added to food is reduced. Additionally, potassium chloride(KCl) can be used, to reduce the levels of Na (sodium) in foods. The latter, however, can impart a bitter metallic taste to foods.
Robert D. Lucas, Ph.D.