Search

The U.S. Department of Agriculture (USDA) in cooperation with the National Heart Lung and Blood Institute and other National Institutes of Health offices and institutes has initiated the National Food and Nutrient Analysis Program (NFNAP). This program is designed to improve the quantity and quality of data in USDA's National Nutrient Databank for approximately 1000 foods. USDA's Key Foods approach was used to set priorities for the foods and nutrients to be analyzed. Sampling plans have been devised to procure nationally representative samples for analysis. Laboratories were qualified to perform the analyses of the various food components. Approximately 250 foods have been analyzed, including approximately 50 fresh fruits, nuts and vegetables. In collaboration with the Produce for Better Health Foundation, the fruits, nuts and vegetables will be analyzed for various phytonutrients, including flavonoids and carotenoids, along with the traditional nutrients. The analytical results and the results of quality control tests performed by the laboratories will be reviewed and, if found acceptable, released in various USDA databases on the Nutrient Data Laboratory Web site (http://www.nal.usda.gov/fnic/foodcomp). Procedures for choosing foods to be analyzed, sampling plans, analytical methodology and quality assurance programs are presented.

Flavonoids are biologically active polyphenolic compounds widely distributed in plants. Intake of flavonoids may be associated with a decreased risk of cancer, cardiovascular disease, and inflammatory disease in humans. Vegetables are one source for flavonoid compounds in the diet. The U.S. Department of Agriculture's Nutrient Data Laboratory evaluated the quality of existing literature from sources around the world and compiled a database containing five subclasses (flavonols, flavones, flavanones, flavan-3-ols, and anthocyanidins) of flavonoids. Fifty-eight different vegetables, 28 herbs and edible leaves, and 4 vegetable recipes were included as part of the development of the USDA flavonoid database for foods (1). Many vegetables, including onions, hot peppers, broccoli, snap beans, kale, and lettuce, contain the flavonol compounds quercetin and kaempferol. Onions, followed by lettuce, are the major vegetable contributors of quercetin to the diet whereas broccoli is the major contributor of kaempferol. Broadbeans and marrow fat peas provide catechins, the flavan-3-ols. Parsley, rutabagas, and celery provide high levels of apigenin, a flavone. Parsley, followed by celery, is the major vegetable contributor of apigenin to the diet. In compiling the database, analytically valid data were assigned confidence codes (A = most confidence, D = least confidence) based on the quality of the sampling procedures, sample handling, analytical methods, and analytical quality control. Although there were no A-quality data for any flavonoid values for vegetables in the database, most vegetables had B- or C-quality data. This database is the first step in evaluating the need and directing research for obtaining new analytical data on the flavonoid content of vegetables. [ABSTRACT FROM AUTHOR]