When dietary phytate is high relative to zinc, the body’s normal adjustment to absorb more zinc during low-zinc periods does not occur. This means zinc absorption remains low despite the body’s need...
Mechanism
Synthesis from 1 study
When you don't eat enough zinc, your gut normally gets better at grabbing it from food—but only if there's no phytate around. Phytate binds to zinc in the gut like a lock, so the gut can't tell it's low on zinc and never turns up the absorption machinery.
Most probable mechanism
When zinc intake is low, the cells lining the intestine normally make more proteins that grab zinc from food and pull it into the body. But when phytate is present in high amounts, it binds to zinc in the gut and stops these proteins from increasing, so the body can't absorb more zinc even when it needs it.
Low dietary zinc reduces intracellular zinc concentration in intestinal epithelial cells.
Reduced intracellular zinc activates signaling pathways that normally increase transcription and membrane insertion of zinc importers such as Zip4.
Phytate in the intestinal lumen forms insoluble complexes with zinc, reducing its bioavailability and preventing the zinc-dependent signaling that triggers transporter upregulation.
Without upregulation of zinc transporters, the capacity of intestinal cells to absorb zinc remains low despite prolonged zinc deficiency.
Evidence from Studies
Supporting (1)
Community contributions welcome
Adaptation in human zinc absorption as influenced by dietary zinc and bioavailability.
Contradicting (0)
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