Aurelo
Does Soy Affect Iron Absorption?
Soy protein lowers non-heme iron absorption, largely because of its phytate.[1]
Based on Hurrell et al., Am J Clin Nutr 1992 · Updated October 10, 2026
Soy protein isolate lowers non-heme iron absorption[1]
Phytate is a major reason iron is poorly absorbed from soy protein: removing it raised absorption four- to five-fold, and even then absorption was half that from egg white.
Phytate is a major factor, and other parts of soy protein add to the effect.
Source [1]Hurrell RF, et al. Soy protein, phytate, and iron absorption in humans. American Journal of Clinical Nutrition. 1992. (PubMed)
Log your supplements and meals, and Aurelo flags pairings like this one in your own stack, with the days they happened.
Get started freeRelated
- Do Iron and Manganese Compete?They are linked: iron deficiency raises manganese absorption and can make manganese toxicity worse.
- Does Vitamin A Help Iron?Vitamin A is needed to mobilise iron, so if iron and vitamin A are both short, address both.
- Does Riboflavin (Vitamin B2) Help Iron?Riboflavin is needed to use iron, so check riboflavin sources such as dairy, eggs and fortified grains when iron is short.
- Do Coffee and Tea Block Iron Absorption?Coffee and tea can inhibit iron absorption: in a study in adults, coffee and tea drunk with a bread meal cut the iron absorbed from it.
- Do Whole Grains and Beans Block Iron?Phytate in grains and beans lowers non-heme iron absorption, but in a typical western diet the effect matters little for most people’s iron status.
- Do Iron and Copper Work Together?Yes. Copper takes part in iron metabolism, and anemia is one effect of copper deficiency, which is uncommon.
Sources
- Hurrell RF, et al. Soy protein, phytate, and iron absorption in humans. American Journal of Clinical Nutrition. 1992. PubMed
This page is general information from the cited sources, not medical advice. If you take prescription medication, are pregnant, or manage a health condition, check supplement changes with a pharmacist or doctor.