Some Antioxidants Increase Anemia, Iron Deficiency Risk


We often hear about the benefits of antioxidants, but a group of scientists are warning that some polyphenol antioxidants may increase the risk of iron deficiency and anemia. Iron deficiency is the most common nutritional deficiency in the world.

The downside of Polyphenol Antioxidants unveiled in a new study

Polyphenol antioxidants are a type of phytochemical (plant-based chemical) found in most legumes and fruits, as well as red wine, chocolate, green tea, olive oil, and vegetables such as broccoli, cabbage, onions, and parsley. More than 4,000 of these antioxidants have been identified and are believed to be instrumental in fighting oxidative stress in humans.

Previous studies have indicated that polyphenols offer or have the potential to provide many health benefits, such as fighting prostate cancer and leukemia, decreasing the risk of heart disease, improving bone health, and helping prevent glaucoma and other eye conditions. A new study, however, points to a possible downside to some polyphenol antioxidants.


In the new study, which was conducted at Penn State, nutritional scientists discovered that certain polyphenols reduce the amount of iron that the body can absorb. This effect can result in iron deficiency and anemia in high-risk individuals, such as pregnant women and young children.

The scientists, led by Okhee Han, assistant professor of nutritional sciences, evaluated the polyphenol antioxidants grape seed extract and epigallocatechin-3-gallate (EGCG), which is found in green tea. They found that these polyphenols interact with iron in such a way in the intestinal tract that the mineral cannot enter the bloodstream, where it is needed to transport oxygen throughout the body.

Han and her colleagues concluded that individuals who are at risk for iron deficiency have an even greater risk if they consume large amounts of EGCG or grape seed extract. Therefore, they warn people who are at risk for this nutritional deficiency “should be aware of what polyphenols they are consuming.” Both of these antioxidants, which are available as extracts, should be used with caution.

Penn State news release, August 23, 2010