Herbal Teas Inhibit Iron Absorption
Breaking news from 1999:
Many herbal teas inhibit iron absorption. I hate to hear bad news about people’s good habits, and I particularly don’t like it when it’s from 1999 and I’m just finding out about it now! As I’ve mentioned before, I have been working on an iron article for the Vegetarian Nutrition Practice Group and one of the reviewers pointed me to the study below showing that herbal teas inhibit iron absorption. In the past, I had thought herbal tea did not inhibit iron absorption. Sadly, I was wrong.
The herbal teas tested were camomile, vervain, lime flower, pennyroyal, and peppermint. Cocoa also inhibited iron absorption, as did coffee and black tea. The iron absorption was tested against iron-enriched white bread with only water, and these beverages reduced iron absorption by 50% or more (usually more), with black tea being the worst offender cutting iron absorption by about 80%+.
The good news is that this study pinpoints a benefit of iron-enriched white bread! Who would have thought that white bread could be healthier than herbal tea? Guess it all depends on your perspective.
If your iron status is always fine when tested, then I don’t see a need to change your tea drinking habits; but if you have a tendency towards iron deficiency, it’s probably a good idea to avoid drinking tea with meals.
I have updated the Iron section of VeganHealth.org to reflect this study.
Hurrell RF, Reddy M, Cook JD. Inhibition of non-haem iron absorption in man by polyphenolic-containing beverages. Br J Nutr. 1999 Apr;81(4):289-95. | link