Fitness

Under normal conditions, a healthy person runs little risk of deficiencies of sodium and chlorine. In extremely hot weather, however, so much salt can be lost through perspiration that death may result. Death from salt deficiency occurred during the first years of work on Boulder Dam and similar projects. During the blistering summer of 1933 I corresponded with an engineer who was working on Parker Dam. Each letter contained some such cheerful note as, “We had a wonderful cook but he died yesterday of heatstroke.” The symptoms of sunstroke also are now recognized as caused largely by loss of salt through perspiration.

A lack of salt causes symptoms varying in severity from mild lassitude, weariness or hot-weather fatigue, common during heat waves, to heat cramps, heat exhaustion, or heatstroke, familiar to people who work in iron foundries, furnace or boiler rooms, and industrial plants such as steel or paper mills. Even persons who foolishly play tennis or take similar exercise in hot weather may suffer from heatstroke. The symptoms of heatstroke are nausea, dizziness, exhaustion, vomiting, and cramps in the legs, back, and abdominal muscles or any muscles being used at the time. Without salt, the more water drunk, the worse the condition becomes. Persons working in extreme heat are now advised to take a salt tablet with each drink of water. During hot weather, salty foods, such as salted nuts or soybeans, cheeses or potato chips, should be kept near the drinking water, and at least one well-salted food should be served with each meal. Too much salt rarely harms a healthy person; if more is eaten than is needed, diarrhea occurs. Since normal people may lose as much as a tablespoon of salt daily in the urine, it is unwise to restrict the salt intake unless advised to do so by a physician. Except during hot weather, the healthy person can allow his taste to be his guide as to the amount of salt to eat.

Another essential element, magnesium, is a component of chlorophyll. This mineral is necessary to the action of some 30 enzymes in the body. The best source is green leaves; like potassium, however, it can be lost if cooking water is discarded. Whole-grain breads and cereals contain some five times more of this mineral than do the refined products. When animals are deficient in magnesium, their hearts usually become abnormal and beat too rapidly; they are extremely nervous and irritable and often have tremors and/or convulsions; slight noises such as turning on a water faucet or an electric fan near by can cause the animals to go into convulsions which may be fatal. The animals’ behavior resembles certain types of insanity more nearly than that produced by any other means.

The blood of persons suffering from extreme irritability has been found to be low in magnesium. Recent work indicates that the soothing effect of vitamin B6 (p. 84) is due to better utilization of this mineral. For years Mrs. Gladys Lindberg, who works as a nutrition consultant, and I have obtained remarkable results in giving vitamin B6 to many persons suffering from nervousness, insomnia, mild or severe tremors, convulsions (epilepsy), or even paralysis agitans (palsy). Reports in medical journals often state that these same conditions have not been helped by vitamin B6. I believe that the difference lies in the fact that we also recommend for every malnourished person a supplement of trace minerals containing magnesium.” It is my guess that magnesium deficiencies are partly responsible for the widespread nervousness, insomnia, and irritability supposedly caused by the “fast pace of modern living.”