Antioxidants

Antioxidants

A category, not a treatment. Many antioxidants are used as treatments for cancer, or as supplementary treatments for cancer (supplements as part of an overall alternative treatment plan.

ANTIOXIDANTS: Beyond Vitamins

Researchers may be losing interest in antioxidant vitamins, but the food industry is just starting to stir it up. You'll find vitamins C and E added to foods like Tropicana Healthy Heart orange juice, Kellogg's Smart Start Antioxidants cereal, and Quaker Take Heart oatmeal.

What's more, the industry is moving beyond vitamins to other candidates. "Now we have a new crop of potential antioxidants," says National Cancer Institute investigator Regina Ziegler.

Furthest along the way to celebrity status are polyphenols. They include anthocyanins (in grapes), catechins (in chocolate, tea, and red wine), flavonols (in onions and apples), hydroxycinnamic acids (in coffee), isoflavones (in soy), and more.(n1)

"But people have to recognize that we haven't found consistent evidence for these new antioxidants, either," notes Ziegler. For example, recent studies found no link between flavonoids and breast cancer or heart disease.(n2,n3)
Among the foods that are gaining antioxidant star appeal are chocolate, coffee, and green tea.
(n1) American Journal of Clinical Nutrition 81: 230S, 2005.
(n2) International Journal of Cancer 114: 628, 2005,
(n3) Annals of Internal Medicine 125: 384, 1996.

CHOCOLATE

The chocolate industry is working hard to turn candy into a health food.

Last year, Nestlé sponsored the 1st International Conference on Polyphenols and Health in Vichy, France. In April, the U.S. Department of Agriculture reported that it had analyzed antioxidants in chocolates, thanks to funding from the industry's American Cocoa Research Institute.

And in July, Mars (makers of M&Ms and other candies) and the Harvard Medical School put on a two-day seminar in Switzerland to discuss the latest research on cocoa's potential health benefits.

"Mars says it is in talks with large pharmaceutical companies for a licensing or joint venture agreement to reproduce the compounds in cocoa shown to improve blood flow," noted USA Today in its report on the conference.
That's fine with researcher Alice Lichtenstein of the USDA Human Nutrition Research Center on Aging at Tufts University in Boston.

"If polyphenols in chocolate are effective at lowering blood pressure or improving blood flow, they should take the compounds out of chocolate and test them as rigorously as any drug," she says. "That way, people can eat them without all the fat and sugar in chocolate."

A recent Italian study reported that 3 1/2 ounces of dark chocolate lowered blood pressure and boosted insulin sensitivity.(n1) "With only 15 people, it was a very small study," Lichtenstein points out. More importantly, "these people were eating 480 calories' worth of chocolate a day."

(It may not be polyphenols, but theobromine--a cousin of caffeine--or something else in chocolate that's responsible, note the authors of the Italian study.(n2) That would be bad news for antioxidant advocates, but good news for chocolate eaters.)

Do Americans really need encouragement to eat more candy? "If you put hot fudge on premium ice cream, you're not neutralizing what's in the ice cream, you're just getting fatter," says Lichtenstein. "If people start adding chocolate to their diets, it would be a travesty because we're all too fat anyway."

(n1) American Journal of Clinical Nutrition 81: 611, 2005.
(n2) American Journal of Clinical Nutrition 82: 487, 2005.

COFFEE
Coffee is a newcomer to the antioxidant scene. It leaped to fame with a study that crowned coffee "America's No. 1 source of antioxidants."

"Antioxidants are your army to protect you from the toxic free radicals which come from breathing oxygen and eating sugar, that start chronic diseases," study author Joe Vinson of the University of Scranton in Pennsylvania told ABC News in August. "Antioxidants help stave off cancer, heart disease, diabetes, and stroke."

But coffee leads the pack in Vinson's study in part because we drink so much of it. "If we were eating more fruits and vegetables, they would be our biggest source of antioxidants," explains Lichtenstein.

What's more, it's not clear that Vinson or others know how to measure antioxidants in food, she adds. "They measure something called antioxidant capacity in test tubes, but we don't know what that means."

Researchers have no data to show that antioxidant capacity in the lab translates into how well the body staves off oxidation. For example, Lichtenstein explains, "at high levels, some antioxidants become pro-oxidants"--that is, they promote oxidation.

More importantly, so many people drink so much coffee that studies can pick up any links with disease (whether or not anti-oxidants are responsible).

Though coffee doesn't seem to protect against heart disease or most cancers, some studies suggest that coffee drinkers have a lower risk of Parkinson's disease(n1) and gallstones(n2) and that people who drink four or more cups a day have a lower risk of diabetes.(n3) And liver cancer is less common in coffee drinkers in Japan (where the disease is more common than in the US.).(n4)

"It's not as though someone is trying to withhold some incredible findings about coffee," says Lichtenstein.
(n1) Annals of Neurology 50: 56, 2001.

(n2) Gastroenterology 123: 1823, 2002.
(n3) Journal of the American Medical Association 294: 97, 2005.
(n4) International Journal of Cancer 116: 150, 2005.

GREEN TEA

Lipton Green tea "naturally contains protective antioxidants," says the box. "This is important because antioxidants can help the body protect itself against free radicals--molecules that can damage cells."

To look at Lipton's labels ads, and Web site (www.teaandhealth.com), you'd think that drinking green tea is a slam dunk for anyone who wants to avoid cancer.

Yet in June, the Food and Drug Administration turned down a petition from a small company, Dr. Lee's TeaForHealth, to claim that green tea reduces the risk of cancer. Well, the FDA didn't exactly deny the request. Instead, the agency agreed to allow this not-exactly-glowing claim:

"Two studies do not show that drinking green tea reduces the risk of breast cancer in women, but one weaker, more limited study suggests that drinking green tea may reduce this risk. Based on these studies, FDA concludes that it is highly unlikely that green tea reduces the risk of breast cancer."

Of course, you'll never see that claim on a label (though you'll find a misleading distortion of it on TeaForHealth's Web site). Nor will you see a similar claim that the FDA approved for green tea and prostate cancer. And the agency decided that "there is no credible evidence supporting a relationship between green tea consumption" and colon, lung, stomach, and six other cancers.(n1)

Even if studies find a lower risk of, say, breast cancer in green tea drinkers, something else about those women may be protecting them. "Green tea may be an indicator of an Asian lifestyle that includes lower body weight, more exercise, lower consumption of meat, and a greater intake of fruits, vegetables, and grains," explains the National Cancer Institute's Regina Ziegler.

And a recent study suggests that green tea may lower the risk of breast cancer only in women with a less-active version of a certain enzyme.(n2)

"Green tea may not help people with the more-active enzyme because the tea doesn't hang around long enough for you to derive the benefit," speculates researcher Anna Wu of the University of Southern California.
Interesting, but way too early to know.
(n1) www.cfsan.fda.gov/%26sim;dms/qhc-gtea.html
(n2) Cancer Research 63: 7526, 2003.

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