Consuming phytic acid with white bread reduces the amount of magnesium the body absorbs, with higher amounts of phytic acid leading to greater reductions in absorption.
Mechanism
Synthesis from 1 study
Phytic acid in food grabs onto magnesium in your gut and locks it into a form your body can't absorb. More phytic acid means more magnesium gets trapped and pooped out instead of entering your bloodstream.
Most probable mechanism
When phytic acid is eaten with food, it binds tightly to magnesium in the gut, creating a solid compound that the body cannot absorb. This bound magnesium passes through the digestive tract and is flushed out in stool instead of entering the bloodstream. The more phytic acid present, the more magnesium gets locked up this way, leaving less available for the body to use.
Phytic acid dissociates from food in the intestinal lumen under physiological pH conditions
Phytic acid chelates free magnesium ions, forming insoluble phytate-magnesium complexes
The insoluble complexes remain in the intestinal lumen and are excreted in feces, preventing magnesium uptake by enterocytes
Evidence from Studies
Supporting (1)
Community contributions welcome
Phytic acid added to white-wheat bread inhibits fractional apparent magnesium absorption in humans.
Contradicting (0)
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Gold Standard Evidence Needed
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