Hemochromatosis, or high iron levels in the blood, affects about 5 out of 1,000 Americans. People with hemochromatosis absorb more iron than others -- around 30 percent of the iron they consume, as opposed to 10 percent for people without the disorder. Excess iron builds up in organs and tissues, and can damage the liver, pancreas or heart, leading to liver failure, diabetes or arthritis. Drinking tea can help if you have hemochromatosis because it can block iron absorption. The higher the tannin content in the tea, the greater the effect.
Types of Teas
All "real" tea, which comes from the Camellia sinensis plant, contains natural compounds called tannins that affect iron absorption. Black and oolong tea, the most processed teas, contain the most tannins. Herbal teas, made from different plants and herbs, may or may not contain tannins. Herbs high in tannins include red raspberry leaf, blackberry root bark, bilberry leaf, thyme, white willow bark and bayberry.
Tannin Actions
Tannins in tea and other foods interfere with iron absorption because they bind with non-heme iron, the type of iron that comes from plant sources. The complexes they form are insoluble, which means they don't dissolve in water and your body can't absorb them. Drinking black or oolong tea with a meal that contains non-heme iron can decrease iron absorption by as much as 60 percent, according to the Colorado State University Extension.
Studies
A German study published in the 1998 issue of "Gut" tested the effects of black tea on iron absorption in 18 subjects with proven hemochromatosis. The study found that drinking black tea with meals reduced the increase of stored iron by around 33 percent. A Japanese study reported in the September 1990 issue of "Nippon Ronen Igakkai Zasshi" found no inhibitory effect on iron absorption taken in tablet form with green tea in 11 elderly subjects.
Considerations
According to the study published in "Gut," iron absorption decreased less than expected in people with hemochromatosis who drank tea with meals instead of water. Subjects who drank tea needed less iron removed via phlebotomy, the accepted treatment for hemochromatosis, but they still needed phlebotomy therapy. If you have hemochromatosis, do not rely on drinking tea to decrease your iron stores. Talk with your doctor about conventional medical treatments for this disorder.
References
- "Gut"; Clinical Trial on the Effect of Regular Tea Drinking on Iron Accumulation in Genetic Haemochromatosis; J. Kaltwasser, et al.; November 1998
- Beth Israel Medical Center and Care Group; GI Modifiers: Tannins; 2000
- National Institute of Diabetes and Digestive and Kidney Disorders; Hemochromatosis; April 2007
- Nuffield Advanced Chemistry; Food Science; December 2006
- "Journal of Nutrition"; Overview of Dietary Flavonoids: Nomenclature, Occurrence and Intake; Gary Beecher; 2003
- "Nippon Ronen Igakkai Zasshi"; Effect of Green Tea on Iron Absorption in Elderly Patients with Iron Deficiency Anemia; K. Kubota, et al.; April 1990
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