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.
Daily Nutrition
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 Mayo Clinic lists recommended U.S. daily allowances of zinc for adults as 15 mg for men and 12 mg for women. Women who are pregnant should consume 15 mg each day, and women who are breast-feeding should consume between 16 and 19.
Zinc Deficiencies
If you don't have enough zinc, Corson writes, you can suffer serious complications such as "abnormal development, psychological disorders, anorexia, and movement disorders." The Mayo Clinic adds that zinc deficiency may lead to "poor night vision and wound-healing, a decrease in sense of taste and smell, a reduced ability to fight infections, and poor development of reproductive organs."
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 Mayo Clinic adds, other foods that contain zinc are "lean red meats, seafood (especially herring and oysters), peas, and beans." Galvanized cookware may also leach zinc into your food, adding to your nutritional intake.
Decreased Zinc Absorption
The Mayo Clinic notes that "food stored in uncoated tin cans may cause less zinc to be available for absorption from food." Additionally, 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.
Larsen also mentions that birth control pills can lower blood levels of zinc.
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, a website maintained by the U.S. National Library of Medicine, 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 Mayo Clinic, 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.
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