Although the body produces natural antioxidants to neutralize free radical damage, it doesn't produce enough to handle the free radical bombardment generated by the modern world. Your body's natural antioxidant systems were simply not designed to handle rooms full of cigarette smoke, a diet loaded with fat and constant exposure to new and more virulent viruses.

This may change once scientists learn how to genetically alter our genes so that we produce more natural antioxidants. But in the meantime, we do have another option: enhancing our natural antioxidants with man-made antioxidants--in a word, supplements.

Laboratory studies indicate that antioxidant supplements, predominantly vitamins C and E plus beta-carotene and selenium, seem to be able to neutralize free radicals that sneak past the natural antioxidants produced in your cells, says Dr. Harman.

"Nobody really knows what the optimum levels are," he adds. "But I recommend daily doses of 200 to 400 international units of vitamin E and 1,500 to 2,000 milligrams of vitamin C, along with 25,000 international units of beta-carotene every other day. I also suggest that people take one 50-microgram tablet of selenium in the morning and one at night." Some people may experience diarrhea when taking high daily doses of vitamin C.

Will this actually slow the aging process? "Nobody knows," replies Dr. Harman. It does in laboratory animals. But it will be decades before the people who load up on antioxidants live long enough to answer that question for humans, he says.

Yet while we're waiting to find out, one thing seems absolutely clear: Those folks who take supplemental antioxidants or who enrich their diets with antioxidant-rich fruits and vegetables certainly seem to be preventing development of the diseases that can accelerate the aging process.

More than 50 studies conducted during the past decade demonstrated that high intake of foods rich in beta-carotene reduces the risk of cancer. More than 40 studies indicated that vitamin C does the same. And a review of studies that measured the amounts of antioxidants people eat revealed that the one-fourth of the American population consuming the most fruits and vegetables, the primary dietary sources of beta-carotene, vitamin C and selenium, had half of the rate of cancers of the lung, mouth, esophagus, stomach, pancreas, cervix and bladder compared to those who didn't consume as much.

What's more, people who got less of the antioxidant vitamins C and E and carotenoids such as beta-carotene were more likely to develop cataracts and macular degeneration, a vision-destroying disease that affects mainly older people. People who got plentiful supplies of these antioxidants were 37 percent less likely to have heart attacks.

So not only do antioxidants seem to prevent the diseases that accelerate us into old age, they also seem to be helping us to maintain quality of life.

Getting people to eat more as they age is important, says Jeffrey Blumberg, Ph.D., associate director and chief of the antioxidants research laboratory at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University in Boston. But what you eat is also important, he adds.

"In essence, eating a super high quality diet is crucial if you want to do all that you can to stay young longer," says Dr. Blumberg. "It's especially important to key in on good food sources of vitamins C and E and beta-carotene." Good sources include orange and yellow vegetables, fruits and whole grains.

"In addition, I'd go so far as to advise people who want to take steps to slow down the aging process to take a daily multivitamin/mineral supplement," he says. "The idea behind this is that you can die 'young' as late as possible."