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Diverse Uses and Preparations of Zinc

In the United States, zinc is available over the counter in several oral formulations, such as zinc acetate, zinc citrate, zinc gluconate, and zinc oxide. It is useful for the treatment and prevention of zinc deficiency, and it is also taken for treating and/or preventing many conditions, including the common cold, recurrent ear infections, asthma, lower respiratory tract infections, macular degeneration, night blindness, cataracts, psoriasis, eczema, and acne. Although no strong evidence supports its benefit for the majority of these problems, some studies have been positive for certain conditions. In particular, use of zinc for deficiency conditions related to malnutrition, diarrhea, and parenteral nutrition has good rationale and supportive evidence. The use of zinc supplementation has been shown to benefit age-related macular degeneration.
The upper tolerable recommended dose of oral zinc in adults is 40 mg/day higher levels have been associated with a decrease in copper absorption, resulting in anemia. Chronic intake of zinc at levels of over 450 mg daily can cause side roblastic anemia, while a 10- to 30-g intake of zinc sulfate can be lethal in adults. Zinc is found in many foods that are part of normal diets, including fortified cereal, meat, poultry, and whole grains. Anyone considering taking a zinc supplement should first consider whether their needs could be met by these dietary zinc sources.
Zinc deficiency requiring supplementation may occur in severe diarrhea; liver cirrhosis; with long-term total parenteral nutrition; and with malabsorption after major surgery from intestinal disorders such as Crohn's disease, sprue, and short bowel syndrome. Vegetarians may need as much as 50% more zinc than non-vegetarians because of the lower absorption of zinc from plant foods. People with alcoholism are also at high risk for deficiencies In a healthy person consuming the US recommended daily allowance (RDA) with appropriate total energy intake, zinc deficiency is unlikely.
Effects of Zinc Supplementation for Specific Conditions
Zinc and the elderly. Small trials have shown a benefit of oral zinc supplementation in reducing the incidence of infections in elderly patients, in whom cell-mediated immune dysfunction and increased oxidative stress may contribute to susceptibility to infection and relative zinc deficiency compared with younger patients. Oral zinc supplementation has not been shown to be beneficial in the healing of leg ulcers even in patients considered to be malnourished, according to a recent Cochrane review.
Zinc and the common cold. Studies have addressed the potential use of zinc for preventing or shortening the duration of the common cold or viral upper respiratory infection. it found 2 well-designed trials providing good evidence that zinc gluconate administered within 24 hours of symptom onset can reduce the duration of the common cold. Zinc formulations for the common cold have not been systematically studied in pregnant and lactating women.
Diverse Uses and Preparations of Zinc
In the United States, zinc is available over the counter in several oral formulations, such as zinc acetate, zinc citrate, zinc gluconate, and zinc oxide. It is useful for the treatment and prevention of zinc deficiency, and it is also taken for treating and/or preventing many conditions, including the common cold, recurrent ear infections, asthma, lower respiratory tract infections, macular degeneration, night blindness, cataracts, psoriasis, eczema, and acne. Although no strong evidence supports its benefit for the majority of these problems, some studies have been positive for certain conditions. In particular, use of zinc for deficiency conditions related to malnutrition, diarrhea, and parenteral nutrition has good rationale and supportive evidence. The use of zinc supplementation has been shown to benefit age-related macular degeneration.

The upper tolerable recommended dose of oral zinc in adults is 40 mg/day higher levels have been associated with a decrease in copper absorption, resulting in anemia. Chronic intake of zinc at levels of over 450 mg daily can cause side roblastic anemia, while a 10- to 30-g intake of zinc sulfate can be lethal in adults. Zinc is found in many foods that are part of normal diets, including fortified cereal, meat, poultry, and whole grains. Anyone considering taking a zinc supplement should first consider whether their needs could be met by these dietary zinc sources.

Zinc deficiency requiring supplementation may occur in severe diarrhea; liver cirrhosis; with long-term total parenteral nutrition; and with malabsorption after major surgery from intestinal disorders such as Crohn's disease, sprue, and short bowel syndrome. Vegetarians may need as much as 50% more zinc than non-vegetarians because of the lower absorption of zinc from plant foods. People with alcoholism are also at high risk for deficiencies In a healthy person consuming the US recommended daily allowance (RDA) with appropriate total energy intake, zinc deficiency is unlikely.
Effects of Zinc Supplementation for Specific Conditions
Zinc and the elderly. Small trials have shown a benefit of oral zinc supplementation in reducing the incidence of infections in elderly patients, in whom cell-mediated immune dysfunction and increased oxidative stress may contribute to susceptibility to infection and relative zinc deficiency compared with younger patients. Oral zinc supplementation has not been shown to be beneficial in the healing of leg ulcers even in patients considered to be malnourished.
Zinc and the common cold. Studies have addressed the potential use of zinc for preventing or shortening the duration of the common cold or viral upper respiratory infection. it found 2 well-designed trials providing good evidence that zinc gluconate administered within 24 hours of symptom onset can reduce the duration of the common cold. Zinc formulations for the common cold have not been systematically studied in pregnant and lactating women. A recent study conducted in children suggested that current data are inadequate to support the use of zinc for the prevention or treatment of the common cold in children.

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