Although most adults should be ingesting between 12 and 15 mg/day of zinc, which is the

Recommended Dietary Allowance, most of them are only consuming between 8 and 11 mg/day. The elderly are getting only between 7 and 10 mg/day. In one study, zinc levels were found to be low in all age-Sex groups, except for 25- to 30-year-old males.

Since zinc is water-soluble, it is easily excreted in the urine, according to Abram Hoffer, M.D., Ph.D., in Orthomolecular Medicine for Physicians. Many foods are deficient in zinc because of:

1) It has been leached out of the soil;

2) 2) Processing removes the richest sources of zinc, such as the germ and bran of grains;

3) 3) Cooking dissolves the mineral, which is lost in the discarded water;

4) 4) Foods that contain chemicals such as EDTA, a chelating agent, remove the mineral.

Hoffer added that signs of a zinc deficiency include: 1) Dwarfism; 2) Skin problems, such as acne, brittle nails and hair loss; 3) Problems in the menstrual cycle of women; 4) Joint pain, and cold extremities; 5) Slow wound healing; 6) Loss of taste and smell; 7) Birth defects; 8) Psychiatric symptoms; 9) Skin and gastrointestinal problems among infants.

Researchers at Hopital Bichat in Paris reported in the American Journal of Clinical Nutrition in 1993 that low-dose zinc supplementation (20 mg/day) improves appetite, thymus activity, serum albumin levels and other indicators of the nutritional status of elderly patients. This therapy poses no harm and may be beneficial to the institutionalized elderly population, the researchers said.

Writing in the South African Medical Journal in 1992, N. Silvis said that

supplementation of diabetics with zinc, selenium, chromium, the В Complex, vitamin С and vitamin E improves glucose tolerance, immune function and wound healing, as well as decreasing the risk of cardiovascular disease.

Mothers who are deficient in zinc are at risk in delivering babies who are susceptible to schizophrenia, congenital defects, low birth weight and other complications, according to R.C. Andrews in Medical Hypothesis in 1992. A zinc deficiency, which may result from seasonal changes in the mother's diet, may cause damage to the regions in the brain of the fetus that are high in zinc. This could later result in episodes of zinc deficiency and schizophrenia in the children, especially males, Andrews said.

T.S. Srikumar and colleagues at the University of Lund in Sweden, followed 16 women and four men who switched from a mixed diet to a lacto-ovovegetarian diet for 12 months. They reported in the American Journal of Clinical Nutrition in 1992 that the vegetarian diet does not supply sufficient amounts of zinc, selenium and probably copper, although it is adequate for magnesium. This diet does reduce concentrations of mercury, cadmium and lead in the hair.

At a meeting of the Federation of American Societies for Experimental Biology, meeting April 1,1993 in New Orleans, Erika L. Trainer and colleagues reported that high doses of a zinc monomethionine complex enhances zinc status without affecting copper levels in immune-deficient diabetics. This form of zinc includes methionine, the sulfur-containing amino acid that protects against free radicals. During the 30-day study, the researchers from the University of California at Davis and the University of California Medical Center in Sacramento, gave 14 diabetics 30 mg/day of zinc monomethionine. Although the supplement increased blood zinc levels by 20 percent, it did not harm copper levels in the blood.

"There has been increasing concern that zinc supplements above the Recommended Dietary Allowance may be causing copper deficiencies," said Dr. Carl Keen, one of the researchers. "The study shows that 30 mg of zinc, double the RDA, as zinc monomethionine, was a safe and effective dose. This has important implications for people with compromised immune systems, such as diabetics, who may need to add zinc to their diet."

Added Dr. Robert Walter, another researcher, "Excess free radical production in diabetic patients is of real concern. Zinc monomethionine reduced the production of superoxide, a free radical, in white blood cells, which could prove to be beneficial for diabetics."

Like other antioxidants, zinc can inhibit free adical formation by protecting cellular sulfhydryl groups against oxidation, as well as competing with prooxidants such as iron and copper for binding sites.

Zinc's antioxidant properties were reviewed by Tammy M. Bray and colleagues of the University of Guelph in Canada, in Free Radical Biology in Medicine in 1990. They found that a zinc deficiency can lead to an increased susceptibility to oxidative damage in cell membranes.

They went on to say that unbound zinc is highly concentrated in the choroid (middle coat) of the eye, the prostate, seminal plasma, fetal/neonatal liver and blood plasma and is more likely to act as an antioxidant in those tissues which have a strong potential for oxidation.

In a review of the signs, symptoms, etc., of macular degeneration, a disorder of the macula of the eye, Michael E. Farber, M.D., et al. reported in Postgraduate Medicine in 1990, that, while zinc has been used as therapy for this problem, vitamin E and vitamin С are thought to be preventive agents due to their antioxidant capabilities.

They also discussed other procedures for this condition, such as laser treatment, low-vision devices such as magnifiers or telescopic attachments to glasses, etc.

A zinc deficiency may be related to Alzheimer's disease, according to Fam. ily Practice News in 1990. The mineral has been found to be in low levels in the hippocampus of the brain in Alzheimer's patients. In addition, zinc seems to prevent the deposition of lead and other toxic metals, which can lead to neurofibrillary tangles in the brain.

The researchers added that a zinc deficiency may also cause abnormal functioning of certain enzymes, resulting in abnormal DNA production and leading to abnormal protein synthesis and the formation of unwanted tangles. In the beginning of the disease, zinc may help to prevent the neurofibrillary tangles from forming. Depending on who is counting, zinc is involved in between 80 and 200 enzymatic reactions in the body.

In a French study reported in ACTA Derm Venereol (Stockholm) in 1989, B. Dreno and colleagues reported that 30 mg/day of zinc sufficiently improved patients with inflammatory acne over controls. The mineral's effectiveness is related to its action on inflammatory cells, the researchers said.

Zinc supplementation has previously been shown to be beneficial in male sterility and in reducing complications during pregnancy, reported Alain-Emile Favier in Biological Trace Element Research in 1992. The mineral is beneficial because of its multiple action on the metabolism of the androgen hormones, estrogen and progesterone, as well as with prostaglandins, the researchers said.

They concluded that in reviewing the role of zinc and reproduction, there is very low risk when zinc is given in conjunction with other nutrients. In the studies that were evaluated, dosages ranged between 10 and 60 mg/day.

Since zinc is needed for protein synthesis, zinc supplementation has been shown to be beneficial in wound healing when patients are deficient in the mineral, according to Ananda S. Prasad, M.D., Ph.D., in Consultant, May 1990.

Prasad added that this therapy should consist of 25 mg of zinc, given twice daily one hour before breakfast on a fasting stomach, and at night three to four hours after meals.

The best food sources of zinc are oysters, liver, beef, spices, wheat bran, wheat germ, pork, lamb, poultry, nuts, peanut butter, cheddar cheese and popcorn.

Health food stores carry a variety of zinc supplements, both in individual potencies and in multiple vitamin-min-eral formulations. The new zinc monomethionine is also available.