New data available on antioxidants.

Many chronic and degenerative diseases--cancer, heart disease, Alzheimer's and Parkinson's--are believed to be caused, in part, by oxidative stress. Oxidative stress has also been implicated in the process of aging. Reactive oxygen species can damage biological molecules, such as proteins, lipids and DNA. While the human body has developed a number of systems to eliminate free radicals from the body, it is not completely efficient at doing this.

Measures of the antioxidant capacities of 277 foods have been issued by USDA-ARS scientists in a new database. The database provides easy access to antioxidant values for a wide variety of foods, many of which may be excellent sources of healthful compounds. The database can be harnessed to help guide ongoing research into how antioxidants may correlate to health benefits. While many fruits and vegetables are good sources of antioxidant vitamins, such as E, C, and beta carotene, they also contain other compounds, phytonutrients, which may contribute to health.

Many of the fruits, nuts, vegetables and spices in the database were analyzed for their oxygen radical absorbance capacity (ORAC), which can be used to evaluate the antioxidant capacities of foods. ARS chemists also have examined the ability of antioxidants to be absorbed and utilized within the human body.

Data on foods analyzed using the ORAC method were also gathered during an extensive search of peer-reviewed scientific literature, and screened through a USDA-developed data quality evaluation system. Both the screened data and the analyzed data are listed in the database, along with quality indicators. Antioxidant capacity measures may vary due to different factors, such as the type of cultivar studied and its growing and harvesting conditions, as well as the methods used for a food sample's preparation, processing or analysis.

The new release expands upon the 2004 data release by ARS on estimates of the antioxidant capacity of 171 foods. To access the new database, go to: www.ars.usda.gov/nutrientdata/ORAC.

Further information. David Haytowitz, USDA-ARS Nutrient Data Laboratory, Room 307A, 10300 Baltimore Ave., Building 005 BARC-WEST, Beltsville, MD, 20705; phone: 301-504-0714; fax: 301-504-0713; email: david.haytowitz@ars.usda.gov.

To assist the body, fruits, nuts and vegetables have long been considered excellent sources of antioxidants. A number of minerals and vitamins have a role as dietary antioxidants in addition to their other biological functions.