The relation between antioxidants and memory performance

Carotenoids on the Brain

There’s plenty of evidence that what Tufts researchers found in animals happens in humans. Among 1400 older men and women, those with the highest blood levels of fruit and vegetable antioxidants called carotenoids (beta-and alpha-carotene, lutein, zeaxanthin, cryptoxanthin, and lycopene) were smarter, according to tests at the French government’s medical research institute (INSERM). Indi­viduals with the highest blood carotenoids, indicating they ate the most fruits and vegetables, scored 35 to 40 percent higher on tests of logical reasoning and visual attention than those with the lowest blood levels of carotenoids. Pre­sumably, the high carotenoids produced stronger brain power by shielding brain cells from free radical damage due to aging.

Similarly, Swiss researchers recently found that high blood levels of antioxidant vitamin C and beta-carotene actually predicted a superior memory in old age. In a large ongoing study of aging, Walter J. Perrig, Ph.D., and colleagues at the University of Berne recently tested the memory per­formance of 442 healthy men and women ages sixty-five to ninety-four. Dr. Perrig compared their memory scores with blood samples, taken recently and twenty-two years previ­ously. Strikingly, those with the most blood vitamin C and beta-carotene, at both time periods, scored highest on tests of memory involving recall, recognition, and vocabulary. Thus, high blood antioxidants were an accurate forecast of memory strength two decades later. Researchers concluded that these antioxidants “play an important role in brain aging and . . . the prevention of progressive cognitive impairments.” In short, if you want to preserve your mem­ory as you get old, be sure to take in lots of antioxidants, vitamin C and beta-carotene in particular.

Tomatoes and the Nun Experiments

It’s almost incredible that the amount of tomatoes you eat over a lifetime could help determine how vital your brain is in old age. But striking research by David Snowdon, M.D., at the Sanders-Brown Center on Aging at the University of Kentucky, says it’s true. Dr. Snowdon is director of an ongoing study of aged nuns, many over a hundred years old. He has found that the more lycopene—a potent antioxidant—in their blood, the sharper their mental acu­ity in old age. Lycopene gets into the blood virtually only one way: from eating tomatoes.

In Dr. Snowdon’s study of eighty eight women ages sev­enty-seven to ninety-eight, those with low blood lycopene were least able to take care of themselves in old age—least able to walk, bathe, dress, and feed themselves. Such women with a “lycopene deficiency” in fact were nearly four times more apt to require assistance than those with above average lycopene. Dr. Snowdon theorizes that antiox­idant lycopene in tomatoes helps neutralize free radical chemicals throughout the body, including the brain, keep­ing it intact and functioning better and longer. Indeed low cognitive function, presumably related to free radical dam­age in the brain, strongly predicted a progressive loss of independence in activities of daily living.

Although watermelon and pink grapefruit contain smidgens of lycopene, by far the major source is the tomato, notably processed tomato products, such as tomato paste, tomato sauce, and canned tomatoes. A recent Italian study showed that eating tomato puree with 16.5 milligrams of lycopene daily for twenty-one days boosted the blood’s antioxidant capacity dramatically. Free radical damage to cells’ DNA (genetic material) dropped an astonishing 33 per­cent.

WHERE TO FIND BRAIN-SAVING LYCOPENE

1 ounce

Tomato paste                               16 mg

Tomato ketchup                            5 mg

Spaghetti sauce                              5 mg

Tomato sauce                                5 mg

Tomatoes, canned                         3 mg

Tomato soup                                 3 mg

Tomato juice                                 3 mg

Vegetable juice                              3 mg

Watermelon                                   1 mg

Pink grapefruit                              1 mg

Fresh tomatoes                less than 1 mg