Flavonoid database updated.

What do red grapes, white onions, green and black teas and blackeye cowpeas all have in common? In addition to vitamins and minerals, these plant foods are rich in flavonoids.

The first update of the USDA Database for the Flavonoid Content of Selected Foods, Release 2, is available. The new release provides analytical values for 26 selected flavonoid compounds in 393 foods.

Members of the scientific community, the media and the general public have become interested in the flavonoid content of foods due to their varied biological properties, which include antioxidative and antimicrobial effects. These compounds have also been associated with possible anticarcinogenic or cardioprotective effects. Flavonoid production is enhanced by various stressors in plants, such as fungal or bacterial infection or exposure to UV radiation.

A food composition database for flavonoids in foods is required to evaluate associations between flavonoids intakes and risk factors for various diseases. An exhaustive literature review was conducted that yielded approximately 475 articles on flavonoids published since 1970. Ninety-seven articles contained analytical data which met the criteria for acceptability.

For the update, USDA scientists analyzed the flavonoids in nearly 60 representative fruits, nuts and vegetables taken from a U.S. nationwide sampling. In addition, they evaluated data from nearly 100 new scientific papers on the flavonoid content of various foods for inclusion. The new release includes the quantities of the 26 selected flavonoids found in 168 new foods that have been added to the original database. Data for many of the food items included in the first release were also updated.

Research studies have consistently provided evidence suggesting an association exists between the consumption of diets high in flavonoids and a reduced risk of cancer and heart disease. Documenting the flavonoid content of foods is essential to researchers who strive to evaluate associations between dietary flavonoid intake and risk factors for various chronic diseases.

This supplemental flavonoid database complements the Nutrient Data Laboratory's (NDL) core product, The National Nutrient Database for Standard Reference, SR19, which is the major authoritative source of food composition information in the United States. Supplemental databases for other phytochemicals found at the NDL website include those for proanthocyanidins and isoflavones. The new database is accessible from: http://www.ars.usda.gov/Services/docs.htm?docid=6231.

Further information. David Haytowitz, USDA-ARS Nutrient Data Laboratory, Room 307A, 10300 Baltimore Ave., Building 005 Barc-West, Beltsville, MD 20705; phone: [phone]; fax: [phone]; email: [e-mail].