McAllister: Good fruit, veggie colors

Summer is a great time to get serious about upgrading your diet. All around the country, fresh fruits and veggies are ripe, delicious and ready to eat.

If you’re not eating the recommended five to nine servings each day, you’re probably not as healthy as you could be. Diets rich in fruits and vegetables are associated with a lower risk of dozens of chronic illnesses, including obesity, heart disease, diabetes and cancer.

In a study that tracked the health and dietary habits of more than 100,000 adults for 14 years, Harvard researchers found that those with the highest daily intake of fruits and vegetables had the lowest risk of developing heart disease. Men and women who consumed eight or more servings of fruits or vegetables daily were nearly a third less likely to have suffered a heart attack or stroke than those who consumed fewer than one and half servings a day.

Based on the results of their investigation, the researchers determined that for every extra serving of fruits and vegetables the study participants added to their diets, their risk of heart disease fell by 4 percent.

Fresh fruits and vegetables are chock-full of vitamins, minerals and beneficial substances known as phytochemicals. These naturally occurring compounds are responsible for the rich, vibrant colors of plant foods.

Phytochemicals help safeguard the health of plants by protecting them from a variety of environmental toxins and stressors, including insects, ultraviolet radiation from the sun and disease-causing fungi. Scientists believe the beneficial compounds in plants can provide similar protection to the humans who eat them on a regular basis.

Although each color group of fruits and vegetables boasts various phytochemicals, recent research has highlighted the benefits of those found in red, purple and blue fruits and vegetables. Anthocyanins are responsible for the vibrant colors of ripe blueberries, cherries and black currants. They’re also found in rhubarb, red beets, eggplants and plums.

In humans, anthocyanins have been shown to boost levels of brain chemicals that influence memory and learning and promote healthy aging of the eyes. They’re also known to possess potent anti-inflammatory properties, making them useful in the prevention and treatment of arthritis and other degenerative diseases.

A growing body of scientific evidence suggests that anthocyanins have powerful cancer-fighting potential. When researchers at Ohio State University evaluated the effects of anthocyanins obtained from a variety of red, purple and blue fruits and vegetables, they found that each had the ability to inhibit the growth of colon cancer cells to some degree.

While the anthocyanins from radishes and black carrots slowed the growth of cancer cells by more than 50 percent, those obtained from purple corn and chokeberries stopped cancer cell growth altogether. The anthocyanins obtained from purple corn and chokeberries also killed nearly a fifth of the cancer cells while leaving their healthy counterparts unscathed.

While most berries are rich in cancer-fighting anthocyanins, the results of a study published in the journal Nutrition and Cancer suggest that black raspberries may pack the most powerful anti-cancer punch.

For the study, researchers injected laboratory rats with a substance known to trigger the growth of colon cancer. Afterward, some of the injected rats were treated to a diet rich in freeze-dried black raspberries, while the others were fed berry-free rations.

Remarkably, the raspberry-eating rats developed 80 percent fewer tumors than the rats eating the berry-free diet. Scientists believe that the protective properties of black raspberries will hold true in humans as well as in rodents.

In addition to boosting brainpower and fighting cancer, diets rich in red, purple and blue fruits and vegetables may help reduce the risk of obesity. To test the effects of anthocyanins on body weight, scientists with the Agricultural Research Service in Arkansas fed mice a high-fat diet and either regular drinking water or water spiked with anthocyanins from blueberries and strawberries.

After eight weeks, the rodents were weighed and measured. In spite of consuming the same high-fat diet, the mice consuming the anthocyanin-treated water gained substantially less weight and had significantly less body fat than the mice consuming regular drinking water.

To reap all the benefits that anthocyanins have to offer, you’ll need to eat plenty of fruits and vegetables in shades of red, purple and blue. Now that many varieties are fresh, ripe and ready to eat, it’s easier than ever to include them in your daily diet.

Rallie McAllister is a board-certified family physician, speaker and the author of several books, including “Healthy Lunchbox: The Working Mom’s Guide to Keeping You and Your Kids Trim.” Her Web site is www.rallieonhealth.com. To find out more about Rallie McAllister, M.D., and read features by other Creators Syndicate writers and cartoonists, visit the Creators Syndicate Web page at www.creators.com.

Copyright 2009 Creators Syndicate Inc.