When the ratio of phytate to zinc in food is 15 to 1, the amount of zinc the body absorbs from that food decreases by 48.5% compared to lower ratios.
Mechanism
Synthesis from 3 studies
When there's too much phytate compared to zinc in food, they stick together in the gut and form a solid that the body can't absorb. As a result, most of the zinc passes through the digestive system and exits in the stool instead of entering the bloodstream.
Most probable mechanism
When phytate is present in high amounts compared to zinc, it binds tightly to zinc in the gut, forming a solid compound that the body cannot absorb. This prevents zinc from entering the bloodstream, so most of it passes through the digestive tract and leaves the body in stool.
Phytate dissociates in the intestinal lumen and binds to free zinc ions, forming an insoluble complex at physiological pH.
The phytate-zinc complex is resistant to enzymatic breakdown and cannot interact with zinc transporters on the surface of intestinal cells.
Reduced zinc uptake by intestinal cells decreases the amount of zinc delivered into the bloodstream.
Lower systemic zinc levels result in reduced urinary zinc excretion and increased fecal zinc excretion.
Evidence from Studies
Supporting (3)
Community contributions welcome
Adaptation in human zinc absorption as influenced by dietary zinc and bioavailability.
A stable isotope study of zinc absorption in young men: effects of phytate and alpha-cellulose.
A stable isotope study of zinc absorption in young men: effects of phytate and a-cellulose
Contradicting (0)
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