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2001 > October
Fruits and veggies are natural defenders of good health
Phytonuturients—the chemicals that make tomatoes red, blueberries blue, beets purple and carrots orange—are taking their place alongside vitamins and minerals as important maintainers of health.
Or at least they should be, according to Dr. Daniel Nadeau, a clinical assistant professor of medicine at Tufts and an endocrinologist at Central Maine Medical Center in Bangor, Maine.
"For the last century, much of nutrition has been defined in terms of vitamins and minerals," he says. "But if you don't have fruits and veggies in your diet, you are missing out on a wealth of natural defenders." Defenders, according to Nadeau and others, against arthritis, some cancers, heart disease, urinary track infections and age-related memory, motor and vision loss.
These benefits are outlined in a new book, The Color Code: A Dietary Plan for Optimum Health, which will be published by Hyperion Press in March. The book, which was written for a lay audience, is co-authored by Nadeau, Dr. James Joseph, associate professor of nutrition and chief of the Neuroscience Laboratory at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts; and Anne Underwood, a Newsweek health reporter. It was inspired by Joseph's pioneering research on the health properties of phytonutrients in blueberries, as well as studies of the impact of other fruits and vegetables on overall well being.
Joseph and Nadeau, who holds an M.D. and a master's degree in nutrition from Tufts, met five years ago at the annual meeting of the Wild Blueberry Association in Bar Harbor, Maine. They stayed in touch and talked of writing a book. "We thought we'd call it, Find Your Thrill (Again) on Blueberry Hill," quips Joseph.
There are hundreds of phytonutrients, falling into the broad categories of yellow-orange carotenoids and red-blue anthocyanins. They absorb oxygen free radicals, which are unstable molecules that are a normal, but potentially harmful, byproduct of cell functions. Oxygen free radicals—which also are produced by environmental factors such as smoking, radiation and sunlight—are believed to be, as they accumulate, major contributors to the ailments of aging, including motor and memory impairment, heart disease, arthritis and a variety of cancers.
One example: A study at Harvard surveyed 48,000 men about their consumption of fruits and vegetables. It found that heavy consumption of tomato products correlated with a significant reduction in risk of prostate cancer. Nadeau and others credit lycopene, the anti-oxidant phytonutrient in tomatoes, for this result.
While Nadeau says information on phytonutrient research is warmly welcomed by dietitians, his medical colleagues are not always as enthusiastic because nutrition usually has not been a significant part of their education. "I see many doctors, as well as patients, falling victim to the low-carb, high-protein approach, which I think is sheer madness," he says, because it encourages a diet that is carcinogenic and not good for the heart, while discouraging the consumption of fruits and vegetables.
Joseph continues to research the benefits of blueberries, which, among other things, have been found to improve memory. Collaborating with researchers at the University of Florida, Joseph is working worked with double-transgenic mice that have been genetically programmed to have Alzheimer's disease. When fed a diet of blueberries for 11 months, the mice's Y-maze performance was normal, and he recorded in them a higher level of expression of enzymes associated with signal transduction than in the control group.
"Either directly or working as an antioxidant, the diet appears to have an effect on synaptic plasticity—the signal transduction or communication between neurons," says Joseph. He is scheduled to present some of his findings at a Boston Alzheimer's conference in late October.