Turns out that Jack might have lived longer and skipped all that traumatic "fee-fi-fo-fum" business if he'd simply picked the beans off his beanstalk and made a nice stew instead of shimmying up the thing. Small red beans top the U. S. Department of Agriculture's list of antioxidant-rich foods, and many scientists believe that a diet with a good, diverse dose of these foods could lead to a healthier, longer life.
Free radicals run amuck
Free radicals are particles on the edge. They are highly reactive atoms or groups of atoms with an uneven number of electrons. Like any self-respecting obsessive-compulsive, free radicals crave an even number of electrons. Desperate for an electron fix, they roam our bodies ripping electrons off whatever they encounter, like cell walls and DNA. The process is called oxidation.
"It's comparable to rusting," says environmental toxicologist Takayuki Shibamoto, Ph.D., of the University of California, Davis, explaining that just as rust erodes metal parts in a machine, reducing their ability to function, free radicals weaken the abilities of organic materials in our bodies to do their jobs. "It can cause very serious damage—both directly and indirectly," he says. Not only can the oxidative damage weaken the DNA or cell wall, he explains, but that weakening opens the door for diseases such as arterial sclerosis, cancer, diabetes, HIV and Alzheimer's. In fact, aging is sometimes defined as an accumulation of free radical damage.
Normally, the body's natural defense system neutralizes free radicals, rendering them harmless. But the free radicals are gaining on us.
Over the past 50 years, man-made changes in the environment have created situations that promote the development of free radicals in our bodies. "Auto exhaust, incinerators, cigarette smoke … these are all things that create free radicals," Shibamoto says. "Plus, the hole in the ozone layer means we're exposed to more intense [ultraviolet] light than ever before, something that also causes free radicals." Exercise also increases the number of free radicals in our bodies because of the high levels of oxygen intake during intense activity.
Saved by the beans!
This is where the beans—and blueberries and artichokes and a host of other plant-based foods—come to the rescue. These foods contain natural compounds—antioxidants—that defend the body against free radicals and their oxidizing rampage.
There are more than 4,000 compounds in foods that act as antioxidants, including vitamins C and E, beta-carotene, selenium, lycopene, lutein, resveratrol and polyphenols. Our bodies also make some antioxidants, such as melatonin, a sleep-promoting hormone produced by the pineal gland at the base of the brain.
It is thought that some types of antioxidants give free radicals the electrons they crave, essentially neutralizing them, but many questions remain as to how antioxidants stop the raging free radicals. "There are so many shades of gray surrounding how antioxidants work," says Beverly Clevidence, Ph.D., research leader of the Phytonutrients Laboratory at the USDA Human Nutrition Program in Beltsville, Md. "It's a very active field of investigation and so far, results [revealing health-enhancing benefits of antioxidants] have been promising, but there remains a lot to be discovered about how and why."
Fact or fairy tale?
So, can we really find the fountain of youth in a bowl of chili?
A smorgasbord of studies has suggested possible health benefits from antioxidants. One of the most recent, a British study published this spring in the journal Thorax, links higher levels of antioxidant-rich fruit to lower levels of asthma. Studies have suggested antioxidants may promote eye health and prevent macular degeneration, boost the immune system, prevent age-related decline of the brain and nervous system, help prevent cancer and promote cardiovascular health.
Clevidence notes another study, published in 1999, by Jim Joseph of Tufts University, which showed great signs of improvement in the mental acuity and balance of aging rats after they consumed a steady diet of what would be the equivalent of about two cups of blueberries per day in humans. "There's great reason to believe antioxidants would have the same effect on humans," she says.
So far, many studies have only been performed at the cellular level. Using human populations is far more difficult. "Cells only eat exactly what you give them," Clevidence says, "while people in a study might not report exactly what they've eaten or eat all of what they're told to eat. Plus, each person has a different background."
"There's still a surprising amount of confusion among consumers about what antioxidants are and why and if they're important," thanks to conflicting studies, says Jeannie Moloo, Ph.D., R.D., a nutritionist and spokeswoman for the American Dietetic Association. Studies found that in certain cases, excessive vitamin E may actually increase the potential for developing heart disease and cancer; and that too much beta-carotene may increase the risk of lung cancer in smokers and increase the likelihood of a deadly heart attack among heart patients. Moloo notes that these results were controversial because they came from studies whose design didn't allow direct conclusions. "This is still a relatively new part of nutrition science," she says, recommending a diet containing a variety of antioxidant-rich foods.
The antioxidant hit list
The USDA's top 10 antioxidant list includes: small red beans, wild blueberries, red kidney beans, pinto beans, blueberries, cranberries, artichokes, blackberries, dried prunes and raspberries.
Some antioxidant-rich foods are more potent when eaten cooked, including the yellow, red and orange-colored carotenoids, says Clevidence. Cooking makes it easier for the body to absorb their antioxidants. Raw, these types of vegetables are best eaten with a dose of fat, which helps the body absorb the helpful compounds. Clevidence points to an Ohio State University study that found that women who ate salads with fat-free dressing absorbed almost none of the antioxidants from the vegetables they ate, whereas women who ate salads with fat-containing dressing absorbed a lot.
Certain herbs also pack an antioxidant wallop. Weight for weight, dried thyme and basil have as much antioxidant power as vitamin E, says UC Davis' Shibamoto. Starbucks' favorite scientist, Shibamoto is the one who, several years ago, found that a cup of coffee consumed within 20 minutes after being brewed has the same level of antioxidants as three oranges. The coffee study was not the only bright light for those who feared a life of artichokes and prunes. Red wine and cocoa have also been found to be chock-full of antioxidants.
This spring, Emeryville, Calif.-based third-party certifier Scientific Certification Systems launched a program measuring the nutrient levels in produce by designating the Purple Majesty potato as "Certified Antioxidant Rich." Testing by SCS confirms that the potatoes have at least 235 milligrams of anthocyanidins (a subclass of antioxidants) per 148-gram serving—about one and a half potatoes. "This makes it easier for consumers to be sure they're getting the biggest bang for the buck," says Annie Gardiner, the company's spokeswoman. The company plans to certify other produce, including tomatoes, grapes, cantaloupes and berries.
Apart from memorizing the USDA's Top 10 list and looking for SCS stickers on produce, consumers can go by the "United Nations rule," says nutritionist Dave Grotto, R.D., a spokesman for the American Dietetic Association. "If your plate is all one color," he says, "it's time to recruit others." Rich colors often mean rich antioxidants, although an exception is cauliflower, which has antioxidant levels as high as broccoli.
Eating a variety of whole foods is the best strategy, Clevidence says. "That way you're getting a range of antioxidants, and they interact with one another and with the other compounds in the food in all the positive ways that we already understand, and also in the synergistic ways we don't understand yet."
Shara Rutberg is a Boulder, Colo.-based freelance writer.
Natural Foods Merchandiser volume XXVII/number 7/p. 24, 26