Zinc supplements

Zinc supplements are available in various forms such as zinc gluconate, zinc sulfate, zinc picolinate or chelated zinc. Zinc in the form of zinc picolinate may be the best supplement for use in those who do not secrete sufficient picolinate from the pancreas.

Zinc supplements may be best taken first thing in the morning or two hours after meals to avoid the inhibition of absorption by other food constituents. However, taking the supplements with meals helps to reduce nausea which occurs in some people who take zinc on an empty stomach. Supplements should not be taken at the same time as medications, which reduce zinc absorption.

If you regularly take zinc in doses of 25 mg or above it is wise to take 2 to 3 mg of copper to avoid imbalances in the copper-to-zinc ratio.

Zinc supplementsTherapeutic uses of zinc supplements

Zinc supplements are available in various forms such as zinc gluconate, zinc sulfate, zinc picolinate or chelated zinc. Zinc in the form of zinc picolinate may be the best supplement for use in those who do not secrete sufficient picolinate from the pancreas.


Zinc supplements are used in developing countries to treat deficiency-related growth stunting, particularly in young children. A1998 study done in Guatemala showed that daily zinc supplements of 10 mg improved growth in babies suffering from decreased growth rates. Zinc seems to exert these beneficial effects via growth hormones.

Immune system

Zinc supplementation improves immune function in those who are deficient. It increases the activity of the thymus gland, improves antibody responses and enhances the functioning of white blood cells. It has been shown to inhibit the growth of bacteria and possibly viruses. Zinc supplements have also been shown to boost levels of interferon, a protein which is formed when cells are exposed to viruses and which helps to fight infection.

Researchers at the University of Medicine and Dentistry of New Jersey, Newark, tested the effects of one year of supplementation with zinc and other micronutrients on cellular immunity in elderly people. The patients, aged 60-89, were either given a placebo, 15 mg of zinc, or 100 mg of zinc daily for 12 months. The results showed improvements in some aspects of immunity.

In another double-blind, randomized, controlled trial published in 1998, researchers tested the effects of vitamin A and zinc (25 mg as zinc sulfate) supplements in 136 residents of a public home for older people in Rome. The results showed that zinc supplementation improved cell-mediated immune response.

Many studies show beneficial effects of zinc in the treatment of diarrhea, a major cause of death in children in developing countries. Researchers involved in a double-blind trial carried out in India involving almost 600 children aged 6- 35 months found that zinc supplements reduced diarrhea outbreaks.

Oral supplementation with zinc and zinc sulfate gel may shorten healing time in cases of herpes virus infection.

Zinc supplementsCommon cold

There have been several studies of the effect of zinc lozenges on treating the common cold. Some studies have shown benefit while other have not. The authors of a review of the trials, published in 1998 in the Annals of Pharmacotherapy concluded that treatment of the common cold with zinc gluconate lozenges, using adequate doses of elemental zinc, is likely to be effective in reducing duration and severity of cold symptoms. Most benefit is seen if the lozenges are started immediately after the onset of symptoms.

In a 1996 randomized, double-blind, placebo-controlled study carried out in Cleveland, researchers tested the effect of zinc gluconate lozenges on the common cold. The study involved 100 participants, and patients in the zinc group received a lozenge containing 13.3 mg of zinc every two hours. The lozenges reduced the duration of cold symptoms from 7.6 days to 4.4 days. However, some people did not like the taste of the lozenges.

The formulation of the lozenges also appears to be important and the addition of citric acid or tartaric acid which binds to zinc ions seems to reduce the benefit. A1997 study suggests that zinc acetate lozenges may be more effective in treating colds than zinc gluconate, as more zinc ions are released from zinc acetate under physiological conditions.

The most recent study, published in the Journal of the American Medical Association in 1998 did not find zinc lozenges to be effective. The study involved 249 students in grades one through 12, some of whom were given 10 mg zinc lozenges five or six times a day for three weeks and some of whom were given placebo lozenges containing no zinc. The study showed that it took children taking zinc lozenges an average of nine days to get over all their cold symptoms, which was the same amount of time for children who took placebo lozenges. More children who took zinc lozenges reported side effects such as bad taste reactions; nausea; mouth, tongue, or throat irritation; and diarrhea.


Zinc can also be used to enhance wound-healing and both oral and topical preparations have shown benefit. Taken before and after surgery, zinc supplements may speed recovery time. In a double-blind trial published in 1996, 68 patients were involved in an assessment of the effects of zinc supplementation un recovery after severe head injury. One month after injury, those in the zinc group had lower death rates and showed more improvement than those in the placebo group.


Studies are being conducted to see whether zinc supplementation has any benefit in the treatment of AIDS. Some studies have shown improvement in immune function while others have not. In a 1995 Italian study, zinc sulfate supplements (200 mg per day for 30 days) were given to HIV-positive patients receiving the medication azathioprine (AZT). Results showed stabilization in body weight and increases in CD4+ lymphocytes and immune-stimulating hormone levels.


Zinc supplementation in those who are deficient has been shown to improve birth weight and head circumference. In a 1995 study, researchers at the University of Alabama at Birmingham conducted a randomized double-blind placebo-controlled trial involving 580 African-American pregnant women with low blood plasma zinc levels. The women were either given 25 mg of zinc or a placebo. The results showed that in all the women, infants in the zinc supplement group had a significantly greater birth weight and head circumference than infants in the placebo group.

Zinc supplementsSkin

Zinc is vital for normal skin function and has been used externally to treat acne, eczema, psoriasis and rosacea. The use of zinc supplements for the treatment of acne is controversial and the conflicting results may be due to the variation in the types of supplements used in different studies. (See page 503 for more information.)

Eating disorders

Studies have shown that zinc may be of benefit as part of the therapy for anorexia nervosa by improving taste perception and sense of smell which occur as the disease progresses. Zinc supplements have been found to increase the weight gain of anorexia patients.

Researchers involved in a 1994 Canadian randomized, double-blind, placebo- controlled trial gave a daily dose of 100 mg of zinc gluconate, or a placebo to 3 5 female anorexia patients until they achieved a 10 per cent increase in body mass index (BMI). The rate of increase in BMI of the zinc supplemented group was twice that of the placebo group.

Taste disorders

Zinc supplements have been used to improve taste perception in people taking medications which reduce taste sensation, and in cancer patients undergoing radiation therapy. This can be valuable in helping to maintain normal weight and nutrient intake during treatment.


Diabetics often excrete excess zinc in their urine and studies have shown beneficial effects of zinc supplementation. Zinc supplementation in animals improves glucose tolerance, and a study carried out in 1995 in France showed zinc gluconate supplements to improve glucose assimilation in humans.

Prostate problems

Zinc supplements may play a role in the treatment of benign prostatic hyperplasia (BPH), an enlargement of the prostate gland seen in 60 per cent of men between 40 and 59 years of age. Zinc treatment, in the form of zinc picolinate or zinc citrate, may be beneficial in reducing the enlargement of the prostate and to reduce the symptoms. The beneficial effects of zinc may be due to its involvement in hormonal metabolism. Zinc inhibits the conversion of testosterone to a more active form, which causes overproduction of prostate cells. It also inhibits the binding of hormones to receptor cells. Zinc also acts to lower levels of another hormone, prolactin, which controls the uptake of testosterone into the prostate. Increasing zinc levels therefore restricts the actions of the hormones and leads to a reduction in prostate size.

Macular degeneration

Zinc supplements have been used to treat age-related macular degeneration, the leading cause of lack of vision in people aged over 55. In one double-blind study, researchers at Louisiana State University found that patients receiving zinc supplements had significantly less vision-loss than those not taking zinc.

Digestive diseases

Zinc supplementation appears to relieve symptoms of inflammatory bowel disease (IBD) such as reduced appetite, suppressed immunity and impaired taste. IBD patients may not be able to absorb zinc properly, and as oral supplementation does not always appear to improve symptoms, intravenous zinc may be necessary. Zinc supplements have also been used to treat celiac disease.

Other uses

Some studies have shown that zinc supplements can reduce free radical damage to blood fats. In a 1996 Italian study, 25 mg zinc sulfate in 136 elderly people decreased plasma lipid peroxides. This can help to reduce the risk of cardiovascular disease.

Zinc supplements have also been used to treat mild mental complaints and Alzheimer's disease. A recent Japanese study found low blood levels of zinc in people suffering from tinnitus (ringing in the ears). Supplements improved the condition.

Topically administered zinc acts as an astringent and a weak antiseptic. It is also used in eye drops to treat eye inflammation and as a mouthwash to inhibit plaque growth and protect against tooth disease and fungal and bacterial infections.

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