THE HEALING PIGMENTS
Reduce the risk of heart disease
Treat liver disorders
Improve brain function
Possibly inhibit the growth of cancer
When tea first arrived on the shores of England, merchants sold it like snake oil. “Cure your migraines, drowsiness, lethargy, paralysis, vertigo, epilepsy, colic, gallstones, and consumption—guaranteed!” And the public bought it by the ton.
People didn’t get the medical miracles they were hoping for, of course. And yet, they may have gotten something better. Tea, along with dark chocolate, cranberries, grapes, strawberries, blueberries, and other fruits and vegetables, contains tiny crystals called bioflavonoids, or flavonoids for short. These compounds, which give foods some of their colors, have been shown to help prevent a number of serious health threats, including heart and liver diseases.
Scientists have speculated that what make flavonoids so powerful are their antioxidant abilities. Antioxidants help neutralize dangerous oxygen molecules called free radicals, which are found naturally in the body, thus preventing them from damaging tissue and causing disease.
“Lately, however, researchers are moving away from the theory that flavonoids act as antioxidants in the body,” says Joe A. Vinson, PhD, professor of analytical chemistry at the University of Scranton in Pennsylvania, specializing in the study of these compounds. “It seems that it is not always a direct ‘antioxidants trapping free radicals’ story. People are finding out new mechanisms by which they work.”
But the power of flavonoids to help protect the body against certain diseases and conditions—most notably, heart disease—is not in question.
There is a legion of things these compounds do, including boosting immunity, possibly inhibiting cancer, preventing hardening of the arteries, and maybe even slowing down the aging process and boosting brain power.
For years, researchers pondered how the French could drink red wine at lunch and dinner, pack away enough butter and lard to fill a Parisian pastry shop, and smoke just as much or more than Americans do, yet still have heart disease rates 2½ times lower than ours.
While the French may take delight in puffed pastries and smokes, they also eat a lot of fruits and vegetables. This is important because these foods, along with the red wines they enjoy, are good sources of flavonoids, which appear to help stop the process that allows cholesterol to stick to artery walls.
One Italian study examined more than 700 people with a history of heart attack for 8 years and looked at their intake of anthocyanidins, flavonoids found in blue/purple and red fruits such as blueberries, blackberries, cranberries, raspberries, and strawberries. They found that the men with the highest intake of anthocyanidins had the lowest rate of heart attacks, indicating that the flavonoids in these fruits seem to be protective.
In another study, Finnish researchers found that people with very low intakes of flavonoids during a 25-year period had higher risks of heart disease.
And a review published in the Journal of Alternative and Complementary Medicine showed that consumption of both green and black tea led to a decrease in atherosclerosis and an improvement in overall heart health.
There seems to be a common method for several kinds of foods and beverages containing flavonoids to make arteries more flexible and able to deal with the stresses of high-fat foods and exercise, says Dr. Vinson. “So after a meal or exercise, when your blood pressure naturally goes up, your arteries are nice and flexible and able to adjust to the changes in bloodflow,” he says.
Much of the credit for these benefits goes to quercetin, one of the most powerful of the flavonoids, which is found in good amounts in onions and red apples. “Quercetin is a more powerful antioxidant than vitamin E, which is well known for its role in heart disease prevention,” says John D. Folts, PhD, professor of medicine and director of the coronary thrombosis laboratory at the University of Wisconsin School of Medicine and Public Health in Madison.
It’s not only the antioxidant action that makes flavonoids so protective, says Dr. Folts. Evidence suggests that these compounds may also act like a nonstick coating in the bloodstream, preventing platelets, the tiny disks in the blood that cause clotting, from sticking to artery walls and causing blockages.
In European countries, where natural plant compounds are commonly used for their curative qualities, flavonoids have been longtime favorites. For example, European clinics commonly use silymarin, a flavonoid found in certain types of artichokes, to treat alcohol-related liver disorders.
In addition, Dutch scientists have found that giving large doses of silymarin to animals prior to surgery can prevent potential liver damage from oxygen deprivation during the operation.
Just as free radicals in the body can damage blood vessels leading to the heart, they also can damage DNA, the genetic material inside cells that tells them how to function. This DNA damage can lead to cancer. Since flavonoids help block free radicals, it would make sense that they would help prevent cancer as well.
So far, a number of large studies have failed to establish a cancer-protective link. “Unfortunately, the cancer and flavonoids story is never really satisfactory to those of us in science,” says Dr. Vinson. In part, this may be because researchers have concentrated on the major flavonoids, like quercetin, rather than on some of their lesser-known kin.
It appears that some flavonoids, like silymarin and tangeretin, which is found beneath the rind of oranges, lemons, and other citrus fruits, may, in fact, play a role in preventing cancer. More research is necessary in this area, however.
In studies on rats, for example, researchers at the University of Madras in India found that silymarin helped stop the growth of a certain form of liver cancer.
“You can never get enough green tea,” says Joe A. Vinson, PhD, who specializes in the study of flavonoids. In studies, green tea appears to be particularly effective at lowering the risk of heart disease and improving cognitive function. “The only reason to worry about getting too much green tea is if you have anemia (the caffeine in green tea can worsen the problem or even bring it on), and even then, all you have to do is take your tea with vitamin C, and you solve that problem immediately,” he says. So drink up!
Flavonoids seem to improve our ability to think as well. A Japanese study looked at the relationship between green tea and cognitive function in humans. They studied the green tea consumption of 1,003 people ages 70 and under and found that those with a higher intake of green tea had a lower presence of cognitive impairment. So it appears that green tea may help protect the brain from age-related decline.
It can be a bit tricky to get enough flavonoids in your diet, not because they’re scarce but because they often hide in out-of-the-way places—in the white stuff beneath an orange rind, for example, or inside an apple’s peel.
The richest sources of flavonoids include green tea, onions, kale, green beans, broccoli, endive, cranberries, and citrus fruits (in the peel and white pulp). Also good are red wines, lettuce, tomatoes, tomato juice, sweet red peppers, broad beans, strawberries, apples (with the skin), grapes, grape juice, and dark chocolate.