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New Laboratory Focuses on Foods That Maintain Health

By Judy McBride
November 25, 1997

Compounds in fruits, vegetables, soybeans, nuts, grains and tea that appear to promote health will get the undivided attention of five scientists in a new Phytonutrients Laboratory at the Beltsville Human Nutrition Research Center. The center is part of the Agricultural Research Service, the U.S. Department of Agriculture’s chief research agency.

“Carotenoids like beta carotene are one group of the compounds called phytonutrients, and we need to know more about phytonutrients and their importance for health,” said Eileen Kennedy, USDA’s deputy under secretary of agriculture for research, education and economics. “Scientists at the new Phytonutrients Laboratory will focus on whether and how phytonutrients in whole foods such as fruits and vegetables contribute to health in ways we haven’t known about.”

The new laboratory includes four scientists, already with the center, who earlier pooled their talents to assess the nutritional effects of carotenoids, including beta carotene, lycopene and lutein. The four scientists determined the extent to which these phytonutrients are absorbed from foods as well as if and how they promote health. The center will hire a fifth researcher, one with a background in phytonutrients.

"We knew we were interested in more than just carotenoids," said nutritionist Beverly Clevidence, who led the earlier studies and will head the new laboratory. “It's an exciting and rapidly growing area.” The field is so new that Clevidence and her colleagues must develop methods for identifying and measuring various phytonutrients before they can study the effects these substances have on the human body.

"What we know about phytonutrients is what was known about vitamins early in this century," said Clevidence. “Scientists then knew they could keep rats alive by adding egg yolk or liver to a diet that otherwise would not sustain the animals. The scientists didn't know what components in egg yolks or liver kept the animals alive. Only later did they discover that these components were vitamins essential to life.”

Unlike vitamins, phytonutrients may not be essential for life, but researchers believe they may be important for optimal health. “We know that fruits, vegetables and probably soy and some grains are important for health,” Clevidence said. “But we don't know all the health-giving components in these foods yet. And science is only beginning to determine how they work."

Deciphering the exact role of phytonutrients won’t be easy, she added. “Many scientists think these components act in concert with one another. This adds a new level of complexity to the research."

It may also explain why some study participants who took beta carotene supplements did not show a change in risk for chronic diseases. Clevidence said it's human nature to look for one substance--a “magic bullet”--that keeps people healthy, but that's unrealistic. Humans evolved eating whole foods, not purified supplements.

"We will emphasize whole foods and want to know if a food or class of foods promotes health and how it works,” she said.

Clevidence said one of the new laboratory's first studies will focus on almond flour. Almonds and nuts in general appear to be a rich source of phytonutrients. The Beltsville researchers want to know how well these substances are absorbed by the body and how long it takes after eating for blood levels to peak.

Another project will focus on measuring black tea’s phytonutrients--known as catechins--that may have antioxidant properties. Later, the researchers will measure catechins in blood plasma.

ARS will sponsor a workshop next March aimed at increasing research on phytonutrients and health nationwide. The agency plans to invite approximately 75 plant and nutrition scientists to discuss ways of increasing phytonutrients in commonly eaten foods.

Scientific contact: Beverly A. Clevidence, PhD, nutritionist and research leader, Phytonutrients Laboratory, Beltsville Human Nutrition Research Center, Agricultural Research Service, USDA, Beltsville, Md., telephone (301) 504-8367, fax (301) 504-9098,