The green tea–iron disconnect

© Getty Images Vesna Sajn
Green tea ©Getty Images Vesna Sajn

Green tea is a well-known antioxidant, and we also know that iron is an important nutrient. However, researchers recently found that consuming green tea and an iron-rich meal at the same time may actually negate the green tea’s health benefits.

Penn State nutritionists Matam Vijay-Kumar and Beng San Yeoh and colleagues published a study yesterday (March 8) in the American Journal of Pathology revealing their findings about the effects of consuming green tea and dietary iron at the same time. You can read the full Penn State News article by Marjorie Miller here.

Epigallocatechin-3-gallate, or EGCG, is the main compound in green tea and is what researchers believe gives the tea its antioxidant and anti-inflammatory properties.

I asked Vijay-Kumar a few questions about this research. Read on to learn more.

Why are antioxidants good for us?
Antioxidants neutralize free radicals and reduce oxidative stress. Free radicals are highly reactive molecules — they damage macromolecules such as lipids and DNA in the cell, respectively causing lipid peroxidation [degradation of lipids] and DNA damage. Oxidative stress is a state of imbalance between generation of free radicals and the ability of the body to neutralized their harmful effects (via antioxidants). Oxidative stress has been implicated as one of the mediators that aggravate many disease conditions, such as inflammation. Hence, reducing oxidative stress would help to restore and maintain balance and health.

What is EGCG and what is its connection to green tea?
EGCG is a major polyphenolic compound in green tea. The antioxidant property of green tea is attributed to the polyphenols present in it. These polyphenols have many forms, but EGCG happens to be the most abundant and the most active/potent antioxidant in green tea.

When green tea and iron are consumed at the same time, what is happening?
When we administer EGCG it offers protection against intestinal inflammation. But when we co-administer EGCG and iron, EGCG loses that protective effect.

Are the health benefits of both green tea and iron lessened when consumed together, or just the tea?
When consumed together, EGCG loses its bioactivity and the availability of iron to the body may be reduced.

Why did you research this effect?
We work on a protein called lipocalin 2. A recent study indicated that lipocalin 2 can bind to EGCG, so we tested to see whether lipocalin 2 prevents the beneficial effect of EGCG.

Editor’s note: Lipocalin 2 is a protein produced by the body’s white blood cells that is known to hold onto iron, limiting bacteria growth, particularly in the gut.

Members of the news media interested in talking to Vijay-Kumar should contact Marjorie Miller at 814-865-4622 or msm39@psu.edu.

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