Phytic acid, a compound found in plant foods, binds to iron, zinc, calcium, and magnesium in the digestive tract, making these minerals less available for absorption by the body.
Mechanism
Synthesis from 4 studies
Phytic acid in foods like whole grains grabs onto minerals such as iron, zinc, calcium, and magnesium in your gut and locks them into solid clumps that your body can't absorb. These clumps just pass through and come out in your stool, so the minerals never get into your bloodstream.
Most probable mechanism
When you eat foods containing phytic acid, it binds tightly to minerals like iron, zinc, calcium, and magnesium in your gut, turning them into solid clumps that your body can't absorb. These clumps pass through your digestive system and leave your body in stool, so the minerals never enter your bloodstream.
Phytic acid dissociates in the intestinal lumen under physiological pH conditions, releasing its phosphate groups that are highly reactive with divalent cations.
Phytic acid chelates free ions of iron, zinc, calcium, and magnesium through its multiple phosphate groups, forming stable, insoluble complexes.
These insoluble complexes resist enzymatic breakdown and remain in the intestinal lumen, preventing interaction with apical membrane transporters such as DMT1 and ZIP4.
The complexes are not absorbed by enterocytes and are excreted in feces, resulting in reduced systemic availability of the chelated minerals.
Evidence from Studies
Supporting (4)
Community contributions welcome
Phytic acid added to white-wheat bread inhibits fractional apparent magnesium absorption in humans.
A stable isotope study of zinc absorption in young men: effects of phytate and a-cellulose
Iron absorption in man: ascorbic acid and dose-dependent inhibition by phytate.
Chemical inhibition of INO1 reduces phytic acid in rice and wheat grains for enhanced micronutrient bioavailability
Contradicting (0)
Community contributions welcome
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