Grapes, Green Tea May Up Iron Deficiency

UNIVERSITY PARK, Pa.Eating a diet high in certain polyphenols can decrease the amount of iron the body absorbs, which can increase the risk of developing an iron deficiency, according to a new study from Penn State University.

Researchers studied the effects of eating grape seed extract and epigallocatechin-3-gallate (EGCG) found in green tea. They used cells from the intestine, where iron absorption takes place, to assess the polyphenols' effect and found that polyphenols bind to iron in the intestinal cells, forming a non-transportable complex. This iron-polyphenol complex cannot enter the blood stream, and is instead excreted in the feces when cells are sloughed off and replaced.

According to the findings published in the Journal of Nutrition, people already at risk for iron deficiency increase that risk if they consume high amounts of grape seed extract or EGCG.

"Iron deficiency is the most prevalent nutrient deficiency in the world, especially in developing countries where meats are not plentiful," the researchers wrote. "People at high risk of developing iron deficiency, such as pregnant women and young children, should be aware of what polyphenols they are consuming."

The researchers examined the heme form of iron found in meats, poultry and fish. Last year, they performed similar research with non-heme iron found in plants. The results of this study on grape seed extract and EGCG in the Journal of Nutrition, showing that eating polyphenols decreased iron absorption.