Ask the Dietitian: Antioxidants

Jessica Jones-Hughes
August 5, 2010
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A curious Equal Exchange tea lover recently inquired, "Is rooibos or green tea higher in antioxidants?" So, let's start from the beginning...

What is an antioxidant? There are many types of antioxidants, most prevalent in fruit, vegetables, nuts, spices, teas, coffee, and red wine. Antioxidant content is hard to measure because of the multiple types and varying quantities, influenced by the type of food, how the food is grown (organic food may have more flavonoids) and processed (processing decreases content). Antioxidants include vitamin A, C, E, flavonoids, beta-carotene, selenium, and beyond.

How do antioxidants work? Have you ever added lemon juice to an apple to stop the browning? The antioxidant (vitamin C) in the lemon juice keeps the apple white by fighting against the oxygen that is damaging apple cells turning them brown. This is the same process that happens in your body. When consumed, antioxidants enter your body and act to prevent or repair free radical damage. Free radicals form when your body breaks down food, or through influences such as smoke or radiation. Free radicals damage cells by oxidizing them (like the browning apple). Antioxidants combat free radicals by slowing or preventing their ability to harm. Damage can play a role in heart disease, cancer and other diseases. Antioxidants also help with immune function and may lower the risk of cancer and infection.

Now, which tea has more antioxidants? All teas contain antioxidants. Green and black teas (plus oolong and white) come from the same species of plant and are simply processed differently. Green tea is processed in a way that preserves antioxidants more than black tea (black tea is oxidized). Rooibos comes from a different plant ("red bush") and has different antioxidants from black or green tea making it hard to compare to green tea. Yet, most studies point that green tea takes the cup in terms of total antioxidant quantity.

Recommendation? There is still a lot to learn about antioxidants, which is why answering which tea has more antioxidants is not black and... red. Your body needs an assortment of antioxidants and nutrients to function and stay healthy. To meet your body's diverse needs, choose a variety of whole foods, teas, coffees and wines, all in moderation.