There are a number of reasons why zinc absorption might be inhibited. Blocked absorption is one, and perhaps the biggest culprits responsible are phytates, a group of phosphate-containing compounds that tightly bind zinc in the intestinal track and prevent zinc absorption. As little as 0.26 grams of phytate will inhibit the absorption of 50 mg of pure zinc. Phytates are found in whole grain breads, whole-wheat products, several cereals, soy, oats, legumes (including peas, peanuts, and peanut butter), beans, corn, nuts, and rice. Unfortunately, several of the foods rich in zinc also contain phytates, so it can be very difficult to increase and monitor zinc levels through diet alone.