Can drinking tea reduce the absorption of iron, contributing to low red cell counts and iron-deficiency anemia?
There are research studies showing that tea drinking reduces the absorption of non-heme iron (that form found in plants as opposed to heme iron found in meats). A recent review of all these types of studies has also recommended that those people at risk for developing anemia limit their tea drinking to between meals or one hour after a meal. (Impact of tea drinking on iron status in the UK: a review, Nelson M, Poulter J. , Hum Nutr Diet. 2004 Feb;17(1):43-54.)
However, another study has shown that 50 mg of vitamin C in a meal can overcome the anti-absorptive activity that molecules like tannins and ligands exhert on non-heme iron in foods. (Effect of ascorbic acid on iron absorption from different types of meals. Studies with ascorbic-acid-rich foods and synthetic ascorbic acid given in different amounts with different meals, Hallberg L, Brune M, Rossander L. , Hum Nutr Appl Nutr. 40(2):97-113, 1986.)
Therefore, my final recommendations to optimize iron absorption for people consuming a plant-based diet would be to:
While I try to follow these guidelines, I am not strict with them, frequently drinking iced green tea with my meals. I regularly drink 4 cups (1 quart) of freshly brewed green tea per day, about half with meals and half between meals. My most recent hemoglobin level (June 2004) was above the lower end of the normal limits (normal range for women 12-16, mine was 13), and that has been achieved without consuming any of the usual high iron animal products like red meats for 9+ years, no iron supplements of any kind, and a "sluggish" bone marrow function.
It is important to remember that anemia has many causes. Only your doctor can determine the reason(s) behind your low red cell counts. Do not consume any iron supplements, folic acid, or vitamin B12 supplements without having a correct diagnosis, recommendation/prescription, and appropriate monitoring by your personal health care professionals.
Diana Dyer, MS, RD
faq posted 8/04
These questions and answers are intended to be of a general informative nature. Please consult with the Registered Dietitian in your cancer center or your health care provider for nutritional advice that can be individualized to your specific medical condition.
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