It was 20 years before Drs. Maibodi and Collip demonstrated similar benefits in a group of "healthy" American children of short stature. Those children whose hair zinc levels were under 140 ppm responded to zinc with a dramatic increase in pituitary growth hormone and testicular hormone, testosterone. When given 50 mg zinc doses these children grew an average of 6.3 cm, ie. about 2 and a half inches a year. A 100 mg daily dose was followed by growth of 3 and a half inches. The doctors observed a reduction in copper levels at the higher but not the lower dose. Later research confirmed that at doses over 50 mg per day zinc can crowd out copper from absorption and cause serious copper-deficiency anemia. In the interest of safety zinc supplements should not exceed 50 mg daily for over a few weeks.
In the meantime, after 1963 Dr. Prasad made additional studies of zinc deficiency, including male infertility. Zinc deficiency was induced in human volunteers by a soy-based diet containing only 2.5 to 5 mg of zinc for 6 to 10 months. He found that within 2 months sperm counts dropped 6-fold, from an average 280 million to 45 million. Recovery took 2 months to almost 2 years! Low testosterone levels also occurred and did not return to normal in
over half the
cases, even
a year and a
half later. Dr.
Abbasi, co-
author,
advised that
strict
vegetarians
who want
children
may need
zinc supple-ments to make up for the fact that animal protein is the only reliable source of zinc.
Using this same zinc-deficient soybean diet these researchers went on to study human zinc deficiency in detail. They observed classic symptoms to be: loss of sex drive, fatigue, anorexia and weight loss. The men lost about 10 percent of their body weight, due either to loss of appetite or slow-down in cellular activity required for protein synthesis.
At about the same time, Dr. Robert Henkin, was advancing in his research on the neurology of taste. He discovered that the taste buds of the tongue require a zinc-containing protein, called gustin, and that gustin is decreased or absent in zinc deficient patients. He also recognized that zinc deficiency is a common denominator in patients with loss of taste sensation due to thyroid, liver or intestinal disease and in some cancers.
Taste and appetite obviously are related, so it is surprising that it took so long before researchers could show that zinc deficiency is a prime cause of anorexia nervosa. Self-starvation is a puzzling and tragic "mental" illness, one that has shown a poor response to psychoanalysis, a better response to combination of tube-feeding and behavior modification, and in the past decade a number of reports of prompt recoveries with zinc therapy.
Dr. Alex Schauss of the Institute of Bio-Social Research in Seattle reports an 85 percent recovery rate in 25 anorexia nervosa patients followed for 5 years. That is a spectacular result, especially when previous treatments offer only 5 percent recovery from this illness where one victim in three dies within 20 years.
An important new twist is that Dr. Schauss and his English colleague, Dr. Derek Bryce-Smith, developed a taste test for zinc deficiency. Anorexia patients cannot taste the zinc solution; whereas normally it is quite metallic and even unpleasant. These researchers also found that anorexia patients are so malnourished that they cannot absorb zinc from tablets and capsules but must be treated at first with a liquid form of zinc sulfate. After two weeks of 60 to 150 mg daily intake most patients improve. This innovation, liquid zinc, is the main reason for their success after previous attempts at zinc therapy failed.
So rapid is the influx of new findings about zinc and so little the encouragement to apply this new knowledge that most physicians fail to integrate zinc therapy into practice. That is truly a shame. Zinc deficiency is common amongst sick people, particularly those with chronic intestinal disease and malabsorption. Mental or physical stress causes extra zinc loss, especially in sweat. Thus runners and athletes are especially at risk. Many common medications, Dilantin for example, increase zinc loss via the intestinal tract.