Zinc contributes to a large number of bodily processes including wound healing, immune response, growth and development and insulin activity. There is no part of the body that stores zinc, so a regular dietary supply is necessary. Unfortunately, some foods and supplements block zinc absorption, according to the 2000 "Journal of Nutrition." Avoiding these foods and supplements can ensure a healthy level of zinc intake.
Fiber and Zinc Absorption
Dietary fiber is not typically well digested. Found in fruits, vegetables and whole grains, excessive fiber in the diet can inhibit the absorption of zinc by binding to it. You should consume 20 to 35 grams of fiber per day, according to the Harvard School of Public Health, but most Americans only get half of this amount. Taking in more than the recommended amount, or having a meal that is particularly high in fiber, may make the zinc unavailable to the body and it is excreted through the intestines. Many grain products, along with other foods high in fiber, also contain phytic acid, which inhibits the absorption of zinc.
Iron Supplements and Zinc
Supplemental iron can inhibit the absorption of zinc when taken at the same time. Supplemental iron is typically non-heme, meaning it comes from sources other than animal products. This non-heme iron competes with zinc for the cells that absorb the minerals, and the cells have a greater affinity for non-heme iron than for zinc.
Soy Protein and Zinc
Soy proteins and other legume proteins contain a chemical called phytic acid. This chemical is an inhibitor of trace mineral absorption, including zinc. Additionally, soy protein itself interferes with the absorption of zinc.
- Nutrition; Paul M. Ensel
- Harvard University: Iron Absorption
- Journal of Nutrition: Influence of Vegetarian Protein Sources on Trace Element and Mineral Bioavailability
- Journal of Nutrition: Dietary Factors Influencing Zinc Absorption
- Harvard School of Public Health: Fiber -- Start Roughing It!
- Linus Pauling Institute: Zinc