Nature's Bounty: Booty Marks

By Daniel A. Marano

Americans have long had a love affair with size. In the supermarket we reach instinctively for plump, perfectly formed produce. Now science suggests it's time to downsize the fruits and vegetables we select for the table while expanding our view of nutrition.

Left to itself, nature copes with drought and other adversities by limiting the size of fruits and vegetables. And that turns out to be good—for us as well as the plants. Compact size concentrates the flavonoid phytochemicals that have significant benefits to human health, such as the deeply pigmented anthocyanins in red grapes and pomegranates.

These bioactive compounds, along with the carotenoids in orange veggies, lycopene in tomatoes, and flavonoids in dark chocolate and green tea, are all so-called secondary phytochemicals—produced by plants as a means to cope with stress. They are not nutrients per se, but they serve important signaling and protective functions in plants—and for our bodies as well.

Flavonoid compounds deliver a triple punch even in small doses. As antioxidants, they scavenge the body for free radicals and neutralize their capacity for cellular damage. They also act as anti-inflammatory agents to combat the stresses of aging and improve cardiovascular and brain function. And they are proving adept at halting cancer.

Plant scientist Mary Ann Lila of the University of Illinois focuses on the phytochemicals and other bioactive compounds in berries, which, she contends, are in a class by themselves. She and neuroscientist James A. Joseph at the USDA's Human Nutrition Research Center on Aging at Tufts University have shown that the flavonoids in berries can cross the blood-brain barrier in animals to improve brain function and even spur neurogenesis. They boost the growth of neurons and cell-to-cell communication in memory centers.

"Modern breeding focuses on qualities to attract the consumer," says Lila. "When we increase the size of a fruit, it is at the expense of the secondary components that would be greater in the wild plant."

The insults and injuries that plants endure in the wild—or the deliberate denial of excess fertilizer, pesticides, and water to cultivated crops—provoke their natural defenses and yield fruit that is seldom bigger but often richer than its commercial cousin. Any plant that survives environmental hardship— drought, extreme ultraviolet radiation, or cold temperatures, known collectively as abiotic stress—might not look the best or yield the most uniform and sizable fruit. But it tends to carry more flavor and nutrients, as well as flavonoids of such medicinal value they're often referred to as "nutraceuticals."

In parts of Alaska, the short, harsh growing season delivers extreme ultraviolet stress in the form of 23 hours of daylight—and tiny berries that, Lila reports, are "jam-packed with phytochemicals."