Antioxidants

According to the American Heart Association (AHA), embracing antioxidants in their natural state is the way to go. While eating a diet high in fruits and vegetables has been shown to decrease the overall risk of cardiovascular disease, a review of research conducted on antioxidants between 1994 and 2002 revealed that supplements have no effect on preventing or treating the disease.

Sara Blackburn, Associate Professor of Clinical Nutrition at Indiana University-Purdue University Indianapolis, agrees with AHA recommendations. She says more research is needed to determine the effectiveness of supplements -- the role oxidative stress plays in the development of heart disease has yet to be clarified, among other things -- though certain individuals, like those with metabolic conditions, may need them.

"When looking for antioxidants, a good place to start is with the five servings of fruits and vegetables that the government guidelines prescribe," says Blackburn. "Synergism happens with the nutrients you eat, so it's important to get a colorful balance of functional foods on a daily basis."

Antioxidants exist in foods as vitamins (i.e. A, C, E), minerals (selenium), carotenoids (lycopene) and polyphenols. Our need for them is derived from a paradox in metabolism. Our bodies require oxygen to function, but oxygen is highly reactive, and creates byproducts through oxidation. These byproducts, called free radicals, have the potential to damage cells. Antioxidants, as the name reveals, can stabilize free radicals before they cause harm.

Our defenses against oxidative stress decrease over time, which is why antioxidants are often described as anti-aging agents. Oxidation is a normal process that occurs in the body though, so achieving a balance with antioxidants is crucial to maintaining good health.

In fact, an overabundance of antioxidants can actually have the reverse effect. For example, the use of supplemental carotene has been shown to contribute to an increased risk of lung cancer in smokers. And taking excessive amounts of carotene can turn good cholesterol into bad cholesterol.

"Too many antioxidants can become pro-oxidants," says Blackburn. "However, we usually see this happening when someone abuses supplements, and not from eating too many carrots. The reality is that people are still not getting enough fruits and vegetables to achieve proper antioxidant benefits. In Indiana, on average, people are consuming only 1.5 servings per day, and we're recommending at least five."

Studies have shown that antioxidants may be effective in preventing macular eye disease and reducing the risk of some cancers. Other research suggests that combining certain fruits and vegetables (the synergistic effect Blackburn mentioned) can lead to even greater reduction of these risks and other chronic diseases.

A food's antioxidant power is measured in units called ORACs, or Oxygen Radical Absorbance Capacity, referring to how much radical oxygen a food can absorb. One hundred grams of grapes contain 739 ORACs; 100 grams of blueberries contain 2,400 ORACs. And chocolate? A whopping 13,120 ORACs per 100 grams.

Darker foods, like pomegranates and plums, tend to be more antioxidant-rich. Individual colors are important indicators too. Orange foods like sweet potatoes, carrots, and pumpkin contain beta-carotene. Lutein, known for its association with healthy eyes, is abundant in greens.

Because it may be harder to absorb antioxidants from antioxidant-enhanced food products, stick to natural products when possible, says Blackburn. Antioxidants are found in fruits and vegetables, nuts, grains, and some meats, poultry, and fish. Vitamin A-rich foods include liver, milk, and egg yolks; vitamin E is found in broccoli, almonds, and mangos. Whole grains provide selenium.

"Food is an energy source that powers the system," says Blackburn. "Ultimately, the best way to get a wide array of antioxidants is to eat a balanced diet from a variety of healthy sources."