Zinc is a trace mineral essential for human health. Zinc-rich foods include beef and shellfish. Supplementation may be needed to treat or prevent zinc deficiency. Some individuals are unable to get enough zinc from foods or need additional iron for certain medical conditions. Zinc supplements may be beneficial for treating chronic diarrhea and other concerns.
Major Functions
Zinc serves many functions in the human body. It is a catalyst needed for activating approximately 100 enzymes involved in metabolic reactions within the cells. Zinc plays a role in wound healing and protein synthesis. In addition, zinc supports immune system function and normal growth and development--particularly during pregnancy, childhood and adolescence. Zinc is important for cellular division as well as proper taste and smell. Since the body is unable to store zinc, it is essential on a daily basis.
Alleviates Acute Diarrhea
Results from a pooled analysis of randomized controlled trials involving zinc supplementation in developing countries showed that in zinc-deficient or malnourished children, zinc supplementation reduced the duration and severity of diarrhea. The United Nations Children Fund, or UNICEF, and the World Health Organization now recommend short-term zinc supplementation to treat acute childhood diarrhea.
Reduces Age-Related Macular Degeneration
Zinc supplementation may reduce the risk of age-related macular degeneration progressing from a moderate to advanced stage. A large, randomized clinical trial known as the Age-Related Eye Disease Study evaluated the effect of supplementation of high doses of antioxidants, such as vitamin C, vitamin E and beta-carotene, with or without zinc, on the development of age-related macular degeneration. This study involved more than 3,500 individuals during a six year period. Only supplementation of antioxidants plus zinc significantly reduced the progression of age-related macular degeneration.
Special Population Segments
While most individuals either consume enough zinc-rich foods to meet their needs or obtain enough through a multivitamin and mineral supplement; some specific populations need additional zinc. According to epidemiological data, it is estimated that zinc intake among older adults may be marginal. Even when accounting for intake from both food and supplements; 20 to 25 percent of individuals aged 60 and older have inadequate zinc status. Other at-risk groups include vegetarians, alcoholics, individuals with gastrointestinal diseases, older children that are exclusively breastfed and pregnant or lactating women. For optimal health, these individuals require zinc supplementation.
Forms and Considerations
Supplements typically contain several forms of zinc, such as zinc sulfate, gluconate and acetate. However, the percentage of elemental zinc varies by form. The elemental zinc content is listed on the Supplement Facts panel on the container. There is inadequate research regarding whether there are significant differences among the various forms of zinc in terms of degree of absorption and tolerability. As zinc competes with other minerals for absorption in the body, such as copper and iron, you should check with a medical professional prior to taking any dietary supplements.
References
- National Institutes of Health: Office of Dietary Supplements--Zinc Fact Sheet
- World Health Organization and United Nations Children Fund; "Clinical management of acute diarrhoea"; Aug 2004
- Archives of Ophthalmology; "Age-Related Eye Disease Study Research Group. A randomized, placebo-controlled, clinical trial of high-dose supplementation with vitamins C and E, beta carotene, and zinc for age-related macular degeneration and vision loss: AREDS"; Oct 2001
- "Journal of Nutrition"; Mineral intakes of elderly adult supplement and non-supplement users in the third national health and nutrition examination survey; RB Ervin et al.; Nov 2002
- "British Medical Journal"; Dietary antioxidants and primary prevention of age related macular degeneration: systematic review and meta-analysis; EW Chong et al.; Oct 2007
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