The Diet Detective: Your Guide to Antioxidants

The term "antioxidant" is tossed around a lot, but many of you still are not sure exactly what antioxidants are or why they're important. Read on to find out more.

What is "oxidative stress"?

Believe it or not, oxygen—the very thing you need to survive—can harm you. Think of how the flesh of an apple browns when it's exposed to air. That's the effect of oxygen—called oxidation. An antioxidant prevents oxidation. Dipping the cut apple in lemon juice prevents browning. The lemon juice is an antioxidant. Oxidative stress occurs when someone has too many free radicals in his or her body and not enough antioxidants to combat them.

A free radical is a molecule with an oxygen atom missing an electron. In its effort to replace the missing electron, the free radical steals from another molecule, which then becomes a free radical itself. It's a vicious cycle. Antioxidants provide the free radical with its missing electron so that it doesn't have to steal from another molecule, thus stopping the cycle.
Your body produces free radicals as byproducts of functions it performs, such as when you digest foods, when you exercise, or when you're exposed to tobacco and other pollutants.
If there are too many free radicals and not enough antioxidants, the balance is off—there are not enough antioxidants to go around, and the damaged cells become more susceptible to diseases such as cancer or heart disease.

What are some examples of antioxidants?

Antioxidants are found in plants—they protect the plant from ultraviolet light and act as its immune system. Here are a few names that you might have heard: beta carotene, flavonoids, lycopene, vitamin A, vitamin C, vitamin E and selenium.

Can we get antioxidants from a pill?

We're still learning what, if any, differences our bodies recognize when we take supplements instead of getting antioxidants from foods. "Often there's no distinction," says Karen Collins, M.S., R.D., nutrition adviser to the American Institute for Cancer Research. "But sometimes the chemical form may change slightly. One concern about the use of supplements is the issue of synergy—how nutrients and phytochemicals work together differently from the way each one works on its own. (i.e., 1 + 1 = 3 instead of just 2.)"

There is something about the way nature packages fruits and vegetables—the combination of chemicals in plants—that causes them to fight off disease. "High intakes of fruits and vegetables have been associated with a reduced risk for several chronic diseases, including cardiovascular diseases, cancer, type 2 diabetes, osteoporosis and even eye-related disorders such as macular degeneration. Obtaining antioxidants from food is important because foods high in antioxidants also contain other micronutrients and phytochemicals that are important in preventing chronic disease," says Victoria J. Drake, Ph.D., a researcher at the Linus Pauling Institute at Oregon State University. 

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