Polyphenol antioxidants inhibit iron absorption

Aug 23, 2010

Health benefits from polyphenol antioxidants -- substances found in many fruits and vegetables -- may come at a cost to some people. Penn State nutritional scientists found that eating certain polyphenols decreased the amount of iron the body absorbs, which can increase the risk of developing an iron deficiency.

"Polyphenols have been known to have many beneficial effects for human health, such as preventing or delaying certain types of cancer, enhancing and improving , and decreasing risk of heart disease," said Okhee Han, assistant professor of nutritional sciences. "But so far, not many people have thought about whether or not polyphenols affect nutrient absorption."

The researchers, led by Han, studied the effects of eating grape seed extract and epigallocatechin-3-gallate (EGCG) found in . 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. Instead, it is excreted in the feces when cells are sloughed off and replaced.

Iron is necessary to carry oxygen from the lungs throughout the body and for other cellular functions. People already at risk for 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," said Han. "People at high risk of developing iron deficiency — such as pregnant women and young children — should be aware of what polyphenols they are consuming."

Han and her colleagues looked at the heme form of iron found in meats, poultry, and fish. Last year, they performed similar research with non-heme iron found in plants. They published the results of their study on grape seed extract and EGCG in the , showing that eating polyphenols decreased iron absorption.

Both grape seed extract and EGCG are sold in extract form. The results of these studies suggest that consumers should be cautious if using these products.

Han and her colleagues recently received a grant from the National Institutes of Health, National Center for Complementary and Alternative Medicine to expand this research. They will conduct animal studies and eventually hope to do human studies as well. Other authors on the paper include Qianyi Ma, graduate student in nutritional sciences, and Eun-Young Kim, research assistant in nutritional sciences.

Explore further: New compounds protect nervous system from the structural damage of MS

add to favorites email to friend print save as pdf

Related Stories

Iron and copper relationship is studied

Jul 24, 2007

U.S. scientists studying the relationship of iron and copper in the body have found when iron absorption by cells decreases, copper absorption increases.

Culprit Compounds That Block Beans' Healthful Iron Probed

Sep 25, 2009

(PhysOrg.com) -- Familiar beans like reds, whites and pintos are rich in iron, a nutrient essential for our health. But not all of the little legumes' treasure trove of iron is bioaccessible -- that is, available ...

Better Beans Mean Better Health for All

May 11, 2010

(PhysOrg.com) -- Beans that add pleasing tastes and textures to chili, soups, and other favorite dishes may tomorrow be an even better source of an essential nutrient -- iron. That's a goal of Agricultural ...

Recommended for you

Mystery of the reverse-wired eyeball solved

8 hours ago

From a practical standpoint, the wiring of the human eye - a product of our evolutionary baggage - doesn't make a lot of sense. In vertebrates, photoreceptors are located behind the neurons in the back of the eye - resulting ...

Neurons controlling appetite made from skin cells

8 hours ago

Researchers have for the first time successfully converted adult human skin cells into neurons of the type that regulate appetite, providing a patient-specific model for studying the neurophysiology of weight ...

Quality control for adult stem cell treatment

11 hours ago

A team of European researchers has devised a strategy to ensure that adult epidermal stem cells are safe before they are used as treatments for patients. The approach involves a clonal strategy where stem cells are collected ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

ironjustice
not rated yet Aug 24, 2010
Quote: "Iron deficiency is the most prevalent nutrient deficiency in the world, especially in developing countries where meats are not plentiful,"
Answer: Not all researchers agree there is a 'worldwide iron deficiency'. Some actually think the addition of iron to our food propogates disease such as infection and malaria.
"Iron deficiency very uncommon."
"There are multiple causes of severe anemia in Malawian preschool children, but folate and iron deficiencies are not prominent among them."
They've even tried to tell us purple grape juice could be bad because it causes anemia.
"Too Much Grape Juice Could Cause Iron Deficiency"

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.