Zinc has been known to play a role in the biology of plants and animals since it was identified in fungus over a hundred years ago; but only in the past 17 years have we recognized it as essential for human health. In 1939 zinc was found to be the specific activator of carbonic anhydrase, an enzyme required for conversion of carbon dioxide into bicarbonate. This mechanism is the essence of acid-base balance, to maintain homeostasis, a stable ph under changing conditions of stress, exercise, climate and dietary loads. Otherwise we would die.
In the stomach this enzyme is required for the production of hydrochloric acid and hence it is essential for complete digestion. Zinc supplements should be taken with food to minimize stomach irritation. In fact, zinc sulfate has been used medically to induce vomiting. Nowadays, zinc picolinate and other chelates are the preferred zinc supplements because they are less irritating and better absorbed.
Over 200 enzymes have been identified as zinc dependent. For example, it is essential to the function of carbonic anhydrase (ph balance), alkaline phosphatase (release of phosphate from bone and nucleic acids), RNA polymerase (cell division, nucleic acid synthesis and protein synthesis), insulin (glucose utilization), delta 6 desaturase (essential fatty acid utilization), alcohol dehydrogenase (detoxification of alcohol), ALA dehydrogenase (production of blood pigments and oxidative enzymes), zinc-finger proteins (production of steroids), thymulin (immune control), retinol dehydrogenase (night vision), carboxy-peptidase (intestinal protein digestion).
As you can readily see, zinc is involved in healing and repair of all tissues, though skin is most visible (dryness, raised hair follicles and thick callus). It is vital to the production of sex and adrenal cortex hormones. It is also a key to pituitary control of sex drive, menstrual cycles and milk production. It is a control factor of immunity, infection and allergy. It also concentrated in the memory centers of the brain. Zinc depletion can cause memory loss; supplements can sometimes restore mental acuity.
In view of these facts it seems amazing that The Food and Nutrition Board did not regard zinc as essential and did not set an RDA (recommended daily allowance) until 1974. It is even more amazing that even today so few physicians are prepared to think zinc. But doctors are still recovering from a 50-year propaganda campaign by the medical establishment to convince Americans that our diet is adequate. Zinc deficiency was assumed to be a rare condition. In 1976, Dr. Robert Henkin said: "In the farthest reaches of our imagination, I don't think we have any idea how important and how widespread zinc deficiency problems are."
Zinc made headlines in medical news in1963 when Dr. Ananda Prasad went to Egypt and Iran to investigate and seek the cause for the large number of sexually undeveloped male dwarfs there. Dietary inadequacy was obvious: very little protein from animal sources and over-dependence on wheat and unleavened bread. The diet was low in zinc and iron and high in phytic acid, which renders these minerals insoluble. Deficiency was suspected and confirmed also by abnormally low levels of zinc in their hair.
Dr. Prasad fed one group of these adult dwarfs a more complete diet. They grew 2 inches in a year. Another group received diet plus iron supplements and they grew an average of 3 inches in a year. A third group received diet plus zinc and they grew 5 inches. The zinc group also showed a dramatic rate of catch-up sexual development. There was no doubt about the power of zinc in these cases.
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 supplements 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.
Failure to diagnose and treat a nutrient deficiency can prolong illness and delay healing after surgery, no matter how competent treatment is in every other aspect. This adds to costs of medicine, in both the misery and the expense. For example: Dr. Thomas Sedlacek of the University of Pennsylvania found that zinc supplements shortened hospital stays by two thirds in women after gynecological surgery and wound breakdown occurred 4 times less. The savings in hospital medical bills was $4000 per patient in 1976 dollars. That could make an enormous difference in our present crisis in health care.
Zinc supplementation has been found helpful in a large number of illnesses. In general healing is accelerated and resistance to infection enhanced. Dr. Pories and Henzel found the rate of healing tripled after zinc supplementation. This aspect of zinc power applies to every illness where there is inflammation and tissue damage. If the diagnosis includes "itis" the treatment should include zinc! Arthritis, gastritis, pneumonitis, prostatitis, dermatitis, etc.
Atherosclerosis, with arterial plaque and blockage of peripheral vessels, improves after zinc supplements. Dr. Henzel observed improvement in leg cramps and ability to walk longer distances despite no increase in circulation! Apparently zinc improves the tissue vitality and metabolism. Some of this zinc power is due to the partnership between zinc and vitamin A, wherein zinc activates manufacture of RBP (retinol binding protein), required to carry vitamin A (retinol) from storage in the liver to the tissues of the body. This combination of zinc and vitamin A has been found effective in treating acne even in cases where separately they fail. A study by Dr. Gerd Michaelsson in Sweden found an almost 90 percent clearing of acne pimples in patients treated with both vitamin A and zinc. A placebo group showed only 25 percent clearing and vitamin A by itself was only a little better.
Zinc is directly anti-viral and anti-bacterial. Zinc lozenges shorten the duration of the common cold by two thirds, from 11 days to 4, a beneficial affect at least double that of vitamin C!
Zinc deficiency is a prime cause of abnormal fetal development and birth defects, including joined fingers and toes, scoliosis, hydrocephalus, low IQ and immune deficiency. One of the most alarming observations in the field of nutrition-medicine is that immune deficiency in offspring of zinc deficient pregnancies continue to bear immune deficient offspring for two additional generations—even if the diet is corrected to be adequate in zinc. The implications of this study in rats are quite frightening if it holds for humans!
Alcohol greatly increases zinc losses and also interferes with utilization of the vitamin, folic acid. These combination deficiencies can cause full-blown fetal alcohol syndrome, with deformities and mental retardation. It is encouraging that zinc-treated children often increase in mental acuity and score higher on IQ tests.
Acrodermatitis enteropathica is a genetic impairment of zinc absorption. It can produce fatal skin damage and diarrhea in newborns, a syndrome called. Until Dr. Edmund Moynahan thought of testing for mineral deficiency in 1976, these children were treated with an antiprotozoal drug, Diodoquin, which was of some benefit but at risk of optic atrophy and blindness.
Another hereditary disorder, porphyria, causes loss of both zinc and vitamin B6, which are wasted in the urine along with porphyrins, fragments of blood pigments with which they are complexed. Environmental pollution by lead and mercury interferes with the enzymes that convert these fragments into the heme (of hemoglobin). Instead these fragments pile up and must be excreted in the bile and urine—but they carry zinc and B6 out, depleting them. Since both zinc and B6 are active in nerve regulation, it is logical to find that when extra amounts of porphyrins appear the patients are likely to have mood swings, depression, alcoholism and schizophrenia. Aggressive supplementation with zinc and B6 often yields significant improvement.
Another interaction that bears mention is that of zinc and cadmium. Suffice it to say that cadmium is a metal that is often found in nature with zinc. But where zinc is physiologic, cadmium is toxic and capable of causing kidney damage and high blood pressure even at very low doses. Since cadmium acts by interfering with zinc containing enzymes, zinc supplementation is restorative. Zinc competes with cadmium for absorption and supplementation is protective.
It is hard to believe that this metallic element, present in the human body in small amounts, about 2,000 milligrams total, can be so vital to health and recovery from almost every disease. Obvious as the beneficial role of zinc appear to you now, you can bet it is not as obvious to most health professionals. It is up to you to insist on Putting Nutrition First for your health.
©2007 Richard A. Kunin, M.D.