Submitted to: Journal of Food Composition and Analysis
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/14/2004
Publication Date: 1/1/2005
Citation: Holden, J.M., Bhagwat, S.A., Haytowitz, D.B., Gebhardt, S.E., Dwyer, J., Peterson, J., Beecher, G., Eldridge, A. 2005. Development of a database of critically evaluated flavonoids data: application of usda's data quality evaluation system. Journal of Food Composition and Analysis. 18:829-844.
Interpretive Summary: In view of the potential health benefits of flavonoids the USDA's Nutrient Data Laboratory (NDL) has developed a Special Interest Database of flavonoids in selected foods in collaboration with academia and the food industry. Since it is important to evaluate the quality of analytical data to be included in a database the flavonoids values were collected from approximately 125 published articles and rated to assess the quality of critical parameters; sampling plan, sample handling, analytical method, analytical quality control and number of samples analyzed. Ratings were combined to yield a Confidence Code (A through D). Data were aggregated by food and flavonoid component to provide a database with flavonoids estimates and confidence codes. The database was released on the NDL web site (www.nal.usda.gov/fniv/foodcomp). The overall quality of data was good and received B or better confidence code. There are ample data on wines (red, white and berry wines), citrus fruits and teas. The database also contains values for 58 different vegetables, 28 herbs and edible leaves and 4 vegetable recipes. However, most of the data came from Europe and countries other than the U.S. Observed variability due to cultivars, geographic location and climate indicates the necessity to generate US-specific data. The database is being updated to include new flavonoids values generated by the NDL and USDA's Food Composition Laboratory (FCL) for U.S. foods. The evaluation of data quality is the first step in the identification and ranking of US foods for additional analytical work to improve data quality. Furthermore, release of data quality confidence codes with data provides necessary information to investigators to assess the impact of flavonoid intake on risk of various chronic diseases.
Technical Abstract: In view of the potential health benefits of plant phytochemicals USDA scientists in collaboration with scientists in academia and the food industry have developed a Special Interest Database for flavonoid content of selected foods. Extensive literature searches conducted to collect analytical data on flavonoids revealed that of approximately 15 subclasses of flavonoids 5 subclasses-flavonols, flavones, flavanones, flavan-3-ols, and anthocyanidins-are predominant in foods. The 26 most abundant compounds within these subclasses were included in the database. All the data were evaluated for 5 quality evaluation categories, sampling plan, sample handling, analytical method, analytical quality control and number of samples, using the data quality evaluation system developed by the USDA scientists. Confidence Codes (A through D) were then assigned to every acceptable value. The database contains acceptable values for flavonoid contents for 225 selected foods. Only 97 sources (references) out of approximately 475 collected included acceptable analytical data. The database consists of NDB (Nutrient Data Bank) number, food description, name of the subclass, mean flavonoid values for compounds in that subclass, standard errors, number of data points, minimum and maximum values, confidence codes and sources of data. The overall quality of data was good with 64% of the observations receiving B or better confidence codes and the flavan-3-ols subclass receiving better ratings than other subclasses. There are ample data on wines (red, white and berry wines), citrus fruits and teas. The database also contains values for 58 different vegetables, 28 herbs and edible leaves and 4 vegetable recipes. However, data for most vegetables came from 1or 2 sources only. The database was released on the Nutrient Data Laboratory (NDL) web site in March 2003. This is the first comprehensive database for flavonoids in foods. The database is essential for epidemiological studies to assess dietary intake of flavonoids and to estimate potential health benefits. However, the majority of data came from Europe and countries other than the U.S. Due to observed variability in the values it is important to have data for U.S. foods. Currently the database is being updated to include new analytical values for 59 fruits, nuts and vegetables collected as part of USDA's National Food and Nutrient Analysis Program. The evaluation of data quality will help set priorities and further identify the foods to be analyzed in the future as well as areas to improve data quality. Furthermore, release of data quality confidence codes with data will provide necessary information to investigators to assess the impact of flavonoid intake on risk of various chronic diseases. Research supported by N.I.H. Agreement number (NHLBI) Y1-HV-8116-14.