hytate is a the main storage form of phosphorus in plant tissues and can therefore become part of the human diet if plant foods are eaten. However, phytate is not absorbed in humans and some other mammals because they lack the digestive enzyme phytase. Phytase is therefore not a good mammalian source of phosphorus except in ruminants. Controversy exists as to whether phytate is able to bind minerals during humans digestion, and prevent their absorption to the circulation. Early studies and medical reports suggested that phytate could bind calcium and prevent absorption. However, the results of studies vary a great deal because there are so many variables to consider with regard phytate and mineral absorption. However, consensus suggests that phytate is able to bind certain trace minerals, with zinc being particularly well researched to date.
For example in one study1, researchers assessed the absorption of zinc in monkeys using a variety of milk sources. Absorption of zinc from human milk was 65 %, from monkey milk 54 %, from whey formula 60 %, from casein formula 46 %, but from soy formula only 27 %. However, removal of the phytate from the soy increased zinc absorption to 45 %. Repeating the experiment in rats by removing the phytate from soy increased zinc absorption from 16 % to 47 %. Soy was selected because it is known to contain high concentrations of phytate. Therefore phytate may inhibit zinc absorption in mammals, but the long-term effects of diets high in phytate are not fully understood. This is because zinc intake, cooking time, other foods and biochemical individuality are all able to affect the phytate zinc relationship in various ways.
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