The study was designed to investigate the effects of modern agricultural methods on the nutrient content of foods. The researchers chose garden crops, mostly vegetables, but also melons and strawberries, for which nutritional data were available from both 1950 and 1999 and compared them both individually and as a group.
The study, based on U.S. Department of Agriculture data, will appear in the December issue of the Journal of the American College of Nutrition. Its lead author is Dr. Donald Davis of the university's Biochemical Institute in the Department of Chemistry and Biochemistry. His coauthors are Drs. Melvin Epp and Hugh Riordan of the Bio-Communications Research Institute in Wichita, Kan., where Davis is a research consultant.
According to Davis, establishing meaningful changes in nutrient content over a 50-year time interval was a significant challenge. The researchers had to compensate for variations in moisture content that affect nutrient measurements, and could not rule out the possibility that changes in analytical techniques may have affected results for some nutrients.
"It is much more reliable to look at average changes in the group rather than in individual foods, due to uncertainties in the 1950 and 1999 values," Davis said. "Considered as a group, we found that six out of 13 nutrients showed apparently reliable declines between 1950 and 1999."
These nutrients included protein, calcium, phosphorus, iron, riboflavin and ascorbic acid. The declines, which ranged from 6 percent for protein to 38 percent for riboflavin, raise significant questions about how modern agricul
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Contact: Barbra Rodriguez
brodriguez@mail.utexas.edu
512-232-0675
University of Texas at Austin
1-Dec-2004