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Cancer Nutrition Network for Texans

Zinc

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Zinc is a common metal used in many industrial processes including coating iron and steel to prevent rust, as in galvanized.

In biology zinc is essential for life. It’s basic functions in plants and animals are similar, in that it binds with specific proteins, affecting the shape of the protein and thus its function. Zinc is necessary for the synthesis of DNA, RNA and proteins, the translation of the genetic code, and the activity of many of the enzymes that facilitate the chemical processes of life.

Zinc deficiency inhibits many processes including growth, healing, immunity, reproduction, and cognition. Deficiency is commonly associated with poverty and low access to animal flesh, the best food source of zinc. Populations that subsist on foods derived from grains, particularly poorly refined grains, are at risk of deficiency because of binding of zinc by phytate and fiber. Zinc deficiency can also be caused by the stress of severe illness. Zinc is lost from the body, along with other essential cell constituents, when tissues are used to provide the energy essential for life.

It has been recommended that omnivorous men and women consume 15 and 12 mg of zinc, respectively, each day. Persons whose diets do not include flesh foods on a regular basis are at risk of deficiency, particularly if their diets are rich in phytate. Methods of food preparation that destroy phytate, and liberal intakes of legumes and nuts, can be used to improve zinc nutriture. In addition micronutrient supplements that provide the recommended daily intake of zinc offer another way of assuring an adequate intake.

Intakes of zinc supplements that exceed the recommended allowance should usually be avoided. Excess zinc can interfere with processes that require other essential metals, for example copper, and thus cause illness. Persons who are considering taking more zinc than is recommended should consult their physician.

As far as cancer is concerned, present knowledge suggests zinc has no special role in prevention or treatment other than its role as an essential nutrient.


Harold Sandstead, MD is a Human Nutrition Professor for the University of Texas Medical Branch Department of Preventative Medicine and Community Health

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