Nutritionists are beginning to understand, long after ancient cultures did, many vegetables and fruits contain elements that can fight disease and generally improve our health in many ways. Until recently, how and why has been the $64,000 question. But the answers are slowly emerging, thanks to a growing body of work by a variety of researchers.

For example, plant chemicals called phytochemicals can reduce inflammation and eliminate carcinogens while others regulate the rate at which cells reproduce, get rid of old cells and maintain DNA. Although recent research has found fruits and vegetables don’t provide as much protection from cancer as experts once believed, the body needs some of the 25,000 phytochemicals to stay healthy.

Rather than focus on “power foods,” nutritionists advocate plant-based diets that combine to offer the best benefits and bolster their protective powers.

Over time, people have evolved to eat a diverse diet of some 800 plant foods. In fact, the evolutionary process has much to do with why people grew to depend on plant foods for their nutrients and why they are vulnerable to disease if they avoid them. Unfortunately, according to one expert, most eat three: French fries, ketchup and iceberg lettuce. But some of the best foods, ginseng, turmeric and Reishi mushrooms, are so exotic they never make it to the average American dinner table.

Experts suggest people select their servings of fruits and vegetables from seven color groups, such as purple grapes or yellow squash, whose colors are produced by disease-fighting chemicals called carotenoids.

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They also point out that those wanting to skip fruits and vegetables for a dietary supplement could likely miss out on all the advantages by not eating the real thing as well as those researchers haven’t discovered yet. To that end, the American Heart Association recently issued a warning that antioxidant supplements don’t prevent heart disease. In fact, some supplements with beta carotene increase one’s cancer risk.

But antioxidants already in vegetables neutralize free radicals, dangerous molecules produced by the body as well as external sources including smoking and radiation. Unchecked, free radicals attack healthy cells that can lead to arterial problems and Alzheimer’s disease as well as damage to DNA that promotes cancer.

Plant-rich diets can improve health and can slow down or prevent some ailments. The following are some of the combinations of nutrients and foods along with potential problems or benefits they may prevent that have been discovered by various researchers:

• Consuming vitamin C and carotenoids through food and supplements enabled seniors to reach higher scores in reasoning tests. Other foods rich in vitamin C, carotenoids and folic acid--spinach and broccoli--heightened one’s cognitive abilities

• The beta carotene in sweet potatoes and vitamin E in almonds protects cells from damage

• High potassium fruits and vegetables can help control blood pressure

• Inflammation may be interrupted by the use of antioxidants

• Kale, red cabbage and Brussels sprouts, rich in phytochemicals, activate enzymes that break down carcinogens that can cause cancer

• Levels of homocysteine, which has been linked to heart attacks, hardening arteries, strokes and dementia, can be lowered with vitamin B6 found in bananas and folic acid in broccoli and leafy greens

• Links are being investigated between angiogenesis (a process in which tumors secure sources of blood to help them spread and grow) and chemicals found in licorice, blueberries and garlic

USA Today August 11, 2004