Washington DC: Green tea and spinach might sound like a healthy combination, but it is not. A new study has revealed that iron-rich foods strip the drink of its antioxidant powers.
Green tea is touted for its many health benefits as a powerful antioxidant, but experiments in a laboratory mouse model of inflammatory bowel disease suggest that consuming green tea along with dietary iron may actually lessen green tea's benefits.
Study author Matam Vijay-Kumar of the Penn State University said, "If you drink green tea after an iron-rich meal, the main compound in the tea will bind to the iron. When that occurs, the green tea loses its potential as an antioxidant. In order to get the benefits of green tea, it may be best to not consume it with iron-rich foods."
Iron-rich foods include red meat and dark leafy greens, such as kale and spinach. According to Vijay-Kumar, the same results also apply to iron supplements.
The team found that EGCG, the main compound in green tea, potently inhibits myeloperoxidase, a pro-inflammatory enzyme released by white blood cells during inflammation. Inactivation of myeloperoxidase by EGCG may be beneficial in mitigating IBD flare-ups. But when EGCG and iron are consumed simultaneously, iron-bound EGCG loses its ability to inhibit myeloperoxidase.
Adding to this complexity, they found that EGCG can also be inactivated by a host protein, which is highly abundant in inflammatory conditions.
"The benefit of green tea depends on the bioavailability of its active components," said first author Beng San Yeoh, adding "It is not only a matter of what we eat, but also when we eat and what else we eat with it."
The study is published in the American Journal of Pathology.