Zinc is a metal that is required by the human body for many of its normal functions, from neural activity to immune-system efficiency to sexual maturation. For a variety of reasons, however, some people have difficulty absorbing zinc. For this reason, some zinc supplements come in zinc chelate form. Because "chelate" can refer to a variety of chemical compounds that have been bound to zinc, some experts suggest that a supplement isn't so easily absorbed as you might think, depending on what compound zinc is chelated with.
According to University of Virginia researcher James Corson, zinc is the second-most abundant trace element in the human body. You need it for normal growth and health. The National Institutes of Health Office of Dietary Supplements, or NIHODS, lists recommended U.S. daily allowances of zinc for adults as 11 milligrams for men and 8 milligrams for women. Women who are pregnant should consume 11 milligrams each day, and women who are breast-feeding should consume between 12 and 13.
If you don't have enough zinc, Corson writes, you can suffer serious complications such as slowed development, psychological disorders, anorexia, and movement disorders. The NIHODS adds that zinc deficiency may lead to hair loss, poor immune function, delayed sexual maturity, impotence and vision problems.
Zinc in Food
In her entry on zinc on the Ask the Dietitian website, Dr. Joanne Larsen writes that the body doesn't excrete zinc; zinc deficiencies occur by inadequate intake. The primary way to ensure you consume enough zinc is to eat a balanced diet. Larsen notes that oysters are high in zinc, and, the NIHODS adds, other foods that contain zinc are lobster, beef, beans, pork chops and cashews. Galvanized cookware may also leach zinc into your food, adding to your nutritional intake.
Decreased Zinc Absorption
Though zinc is found in whole grains, ingesting large amounts of these have been found to decrease how much zinc you absorb from food. Zinc supplements should be taken two hours before consuming bran, fiber-containing foods, other whole-grain breads and cereals and phosphorus-containing foods such as milk or poultry. Larsen adds that the phytates found in whole grains and beans bind zinc, preventing its absorption into the body. Older adults may also become zinc-deficient due to decreased absorption, which may be caused by medicine or simply by aging. Some medicines can cause the body to lose zinc in increased amounts.
Chelation to Increase Absorption
According to research published by the University of Pittsburgh, chelating can increase the absorption of metals like zinc. "Chelate" comes from a Greek word meaning "claw." The metallic ion -- zinc, in this case -- is held as though by a claw within an organic molecule. MedlinePlus.com suggests several conditions whose treatment may be supplemented by taking chelated zinc, among them diabetes and parasites.
Potential Problems with Zinc Chelate
Zinc may be chelated with a variety of compounds. "Depending on what that compound is," Larsen writes, zinc chelate "may be not absorbed well." You should consult a pharmacist or other medical professional to determine what form of zinc your system can assimilate most efficiently.
Potential Zinc Interactions
According to the Linus Pauling Institute, zinc supplements, including those in chelated form, may exacerbate a copper deficiency. Ask the Dietitian reports that excess zinc can suppress copper and calcium absorption. Because copper is a necessary component of red blood cells, this can have the long-term effect of causing anemia.