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fiber and iron

Phytates in fiber reduce non-heme iron absorption

What's happening

Whole grains, legumes, and high-fiber plant foods contain phytates and oxalates that bind non-heme iron, reducing absorption by up to 50%. Vegetarians and vegans need ~1.8× more iron as a result.

Recommendation

Take iron supplements between meals, or with vitamin C which overrides the phytate-binding effect.

Timing

Take iron at least 1-2 hours away from high-fiber meals

Sources

  • American Journal of Clinical Nutrition
  • PMID: 8780333

Frequently Asked Questions

Can I take fiber and iron together?

Phytates in fiber reduce non-heme iron absorption. Take iron supplements between meals, or with vitamin C which overrides the phytate-binding effect.

How should I time fiber and iron?

Take iron at least 1-2 hours away from high-fiber meals

Is this interaction dangerous?

This interaction is rated “Caution” by Formulate. Whole grains, legumes, and high-fiber plant foods contain phytates and oxalates that bind non-heme iron, reducing absorption by up to 50%. Vegetarians and vegans need ~1.8× more iron as a result.

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Medical disclaimer. This page is for educational purposes only and does not replace advice from a qualified healthcare provider.