Zinc is essential for your health and well-being. Zinc's importance in human nutrition was not really known until the 1960s, when scientists discovered that adolescent males in Iran and Egypt were suffering from delayed growth and sterility due to zinc deficiency. The Office of Dietary Supplements reports that zinc plays important roles in immune function, protein synthesis, normal senses of taste and smell, growth and development, DNA production, cell division and wound healing.
Protein Synthesis
Collagen and keratin, two of the most abundant proteins in your body, form the basic supportive structure for your skin, bones, muscles, tendons, ligaments, cartilage, eyes and internal organs. Collagen is a complex substance whose synthesis requires coiling and cross-linking of long protein strands that are subsequently deposited in sheets, tubes, spheres and other useful structures. Keratin is also a fibrous protein whose unique molecular structure lends it the toughness required to form your hair, nails and the outer layers of your skin. The enzymes that manufacture both collagen and keratin require zinc for their function.
Deficiency
Because zinc is a cofactor for hundreds of enzymes in your body, insufficient zinc intake leads to a variety of symptoms. Growth delay, hair loss, diarrhea, inflamed mucous membranes, deformed nails, decreased immunity and reproductive failure in males are all commonly seen in zinc-deficient individuals. Poor wound healing is another sign of zinc deficiency, and zinc replacement improves wound healing in deficient persons. In contrast, long-term zinc use does not appear to be beneficial for people who are not already zinc-deficient.
Wound Healing
A study published in the August 1999 issue of "Dermatologic Surgery" demonstrated that people with chronic leg ulcers are often zinc-deficient, and such deficiency may impede wound healing. However, according to a May 2009 "American Family Physician" review, current scientific data do not support the long-term use of zinc -- either as a topical or systemic agent -- for wound healing in people whose zinc stores are sufficient. Furthermore, long-term, high-dose zinc supplementation in such individuals can lead to immune suppression, anemia, copper deficiency, lipid abnormalities and an increased risk for advanced prostate cancer in men.
Recommendations
Zinc plays a critical role in normal skin and connective tissue integrity, and people with zinc deficiency often exhibit slowed wound healing. However, long-term use of zinc by individuals whose zinc stores are sufficient does not appear to speed healing, and high-dose zinc supplementation -- 100 mg daily or more -- may actually cause undesirable side effects. Recommended dietary allowances for zinc -- the doses that prevent deficiency -- vary from 2 mg daily for infants to 14 mg for nursing mothers. Daily doses of 15 mg to 30 mg are usually well-tolerated. Ask your doctor if your zinc requirements are being met.
References
- "Staying Healthy with Nutrition: Zinc"; Elson M. Haas, M.D.; 2006
- Office of Dietary Supplements: Zinc
- "Asian-Australasian Journal of Animal Science"; Trace Mineral Nutrition in Poultry and Swine; J.D. Richards, et al.; November 2010
- "American Family Physician"; Zinc: An Essential Micronutrient; R.B. Saper, R. Rash; May 2009
- "Dermatologic Surgery"; Patients with Chronic Leg Ulcers Show Diminished Levels of Vitamins A and E, Carotenes, and Zinc; A.I. Rojas, T.J. Phillips; August 1999
