Which foods provide the most antioxidants?

Artichokes and beans may not be at the top of your list of favorite foods, but when it comes to antioxidants, these veggies earn a coveted place. They are among a growing variety of foods found to contain surprisingly high levels of these disease-fighting compounds, according to a new USDA study, which researchers say is the largest, most comprehensive analysis to date of the antioxidant content of commonly consumed foods.

In addition to confirming the well-publicized high antioxidant ranking of such foods as cranberries and blueberries, the researchers found that Russet potatoes, pecans and even cinnamon are all excellent, although lesser-known, sources of antioxidants, which are thought to fight cancer, heart disease and Alzheimer's. The study appears in the June 9 print edition of the Journal of Agricultural and Food Chemistry, a peer-reviewed publication of the American Chemical Society, the world's largest scientific society.

"The bottom line is the same: eat more fruits and veggies," says Ronald L. Prior, Ph.D., a chemist and nutritionist with the USDA's Arkansas Children's Nutrition Center in Little Rock, Ark., and lead author of the study. "This study confirms that those foods are full of benefits, particularly those with higher levels of antioxidants. Nuts and spices are also good sources."

The new study is more complete and accurate (thanks to updated technology) than previous USDA antioxidant data and includes more foods than the previous study, the researchers say. They analyzed antioxidant levels in over 100 different foods, including fruits and vegetables. In addition, the new study includes data on spices and nuts for the first time.

Among the fruits, vegetables and nuts analyzed, each food was measured for antioxidant concentration as well as antioxidant capacity per serving size. Cranberries, blueberries, and blackberries ranked highest among the fruits studied. Beans, artichokes and Russet potatoes were tops among the vegetables. Pecans, walnuts and hazelnuts ranked highest in the nut category.

Although spices are generally consumed in small amounts, many are high in antioxidants. On the basis of antioxidant concentration, ground cloves, ground cinnamon and oregano were the highest among the spices studied.

Prior says that the data should prove useful for consumers seeking to include more antioxidants in their diet. But he cautions that total antioxidant capacity of the foods does not necessarily reflect their potential health benefit, which depends on how they are absorbed and utilized in the body. Researchers are still trying to better understand this process, he adds.

Currently, there are no government guidelines for consumers on how many antioxidants to consume and what kind of antioxidants to consume in their daily diet, as is the case with vitamins and minerals. A major barrier to such guidelines is a lack of consensus among nutrition researchers on uniform antioxidant measurements. Scientists will soon attempt to develop such a consensus at the First International Congress on Antioxidant Methods, held June 16-18 at the Caribe Royale Hotel and Conference Center in Orlando, Fla., with the ultimate goal of developing better nutritional data for consumers. ACS is the principal sponsor of the meeting.

For now, USDA officials continue to encourage consumers to eat a variety of fruits and vegetables for better health.

- Mark T. Sampson

The online version of the research paper cited above was initially published May 19 on the journal's Web site. Journalists can arrange access to this site by sending an e-mail to newsroom@acs.org or calling the contact person for this release.

For more information on the First International Congress on Antioxidant Methods, please call the contact person for this release.

(EDITOR'S NOTE: Please see attached chart on the top antioxidant capacities of 20 commonly consumed fruits, vegetables and nuts.)

BEST SOURCES OF FOOD ANTIOXIDANTS: TOP 20 FRUITS, VEGETABLES AND NUTS (AS MEASURED BY TOTAL ANTIOXIDANT CAPACITY PER SERVING SIZE)

In order of rank:

1. Small Red Bean (dried) Half cup
Total antioxidant capacity per serving size 13727

2. Wild blueberry 1 cup
Total antioxidant capacity per serving size 13427

3. Red kidney bean (dried) Half cup
Total antioxidant capacity per serving size 13259

4. Pinto bean Half cup
Total antioxidant capacity per serving size 11864

5. Blueberry (cultivated) 1 cup
Total antioxidant capacity per serving size 9019

6. Cranberry 1 cup (whole)
Total antioxidant capacity per serving size 8983

7. Artichoke (cooked) 1 cup (hearts)
Total antioxidant capacity per serving size 7904

8. Blackberry 1 cup
Total antioxidant capacity per serving size 7701

9. Prune Half cup
Total antioxidant capacity per serving size 7291

10. Raspberry 1 cup
Total antioxidant capacity per serving size 6058

1.1 Strawberry 1 cup
Total antioxidant capacity per serving size 5938

12. Red Delicious apple One
Total antioxidant capacity per serving size 5900

13. Granny Smith apple One
Total antioxidant capacity per serving size 5381

14. Pecan 1 ounce
Total antioxidant capacity per serving size 5095

15. Sweet cherry 1 cup
Total antioxidant capacity per serving size 4873

16. Black plum One
Total antioxidant capacity per serving size 4844

17. Russet potato (cooked) One
Total antioxidant capacity per serving size 4649

18. Black bean (dried) Half cup
Total antioxidant capacity per serving size 4181

19. Plum One
Total antioxidant capacity per serving size 4118

20. Gala apple One
Total antioxidant capacity per serving size 3903