Antioxidant Superstars: Vegetables and Beans
Beans and a host of vegetables top the list of antioxidant-rich foods
The lowly bean has been boosted to star status. A ground-breaking study that
looked at numerous foods says beans -- red, black, pinto, kidney -- are
high-octane sources of antioxidants.
Antioxidants are the disease-fighting compounds that Mother Nature puts in
foods to help our bodies stay healthy, explains researcher Jeffrey Blumberg,
PhD, professor of nutrition at Tufts University in Boston. "Our job is to
take advantage of those antioxidants."
The USDA guidelines recommend eating a variety of fruits and vegetables each
day, selecting from all five vegetable subgroups: dark green vegetables,
legumes (beans), starchy vegetables, orange vegetables, and other vegetables.
They also suggest eating at least two and a half cups of vegetables daily for
people eating 2,000 calories.
Which of these are the best antioxidant foods? Researchers used advanced
technology to study 100 fruits, vegetables, and other food sources to measure
the levels of antioxidants. Beans were the clear winners, but so was a quirky
mix of other veggies -- artichoke hearts, russet potatoes, sweet potatoes,
spinach, and eggplant.
Knowing which foods have the most antioxidants is important, because in
today's polluted world, the human body needs all the help it can get to fight
disease-causing free radicals. That's what antioxidants do -- stop free
radicals from damaging other cells in your body.
The biggest class of antioxidants is flavonoids. Researchers have identified
some 5,000 different flavonoids fruits and vegetables, explains Ronald Prior,
PhD, a chemist and nutritionist with the USDA's Arkansas Children's Nutrition
Center in Little Rock, Ark. He authored the groundbreaking antioxidant measure
Yet the body simply doesn't absorb all flavonoids equally well - that is,
not all are as bioavailable as others. "Bioavailability has to do with
absorption or metabolism in the gut, a process we know very little about,"
Here's the science behind it: An antioxidant attached to a fiber or sugar
molecule may require certain enzymes in the gut to help absorption, he
explains. If those enzymes are there, the flavonoid is absorbed. Some
flavonoids simply don't seem to get absorbed. It's still relatively a mystery
what happens in the gut, Prior notes.
Cooking some vegetables even slightly can help boost bioavailability, Prior
says. "Tomatoes are a classic example. Flavonoids in cooked tomatoes are
better absorbed than raw tomatoes. We don't know for sure what's happening in
the gut, but we do know this is true."
However, cooking is not always good. It kills antioxidants in some foods, he
says. Until researchers figure it out, "aim to eat those at the higher end
of the antioxidant chart," says Prior.
The Antioxidant Winner: Beans
Prior's study found beans to be clear winners - one-half cup of red beans
yields 13,727 antioxidants; red kidney beans have 13,259; pinto beans, 11,864;
and black beans, 4,191. Beans are inexpensive and filling. Classic meals such
as beans and rice, beans in a burrito, split pea soup, and a peanut butter
sandwich are bean naturals. (Peanuts are not nuts; they are in the same family
of plants as beans and peas.)