Declining Nutrition of Fruits and Vegetables

[Master Kim]

Government Analysis Indicates Many Minerals Less Abundant

Results from research into Americans' diet habits haven't been good. We're consuming more calories than ever, many of them from unsaturated fats, and as a result, we're getting fatter, and probably unhealthier.

But if a person should decide to improve his or her diet and eat the foods doctors and dieticians recommend for better health, would it be enough? Actually, there is some evidence that the fruits and vegetables available to most people today don't contain the nutritional value they had about 40 or 50 years ago.

Declining Nutrition of Food In 2004, a University of Texas research team headed by biochemist Donald Davis, Ph.D., analyzed a U.S. Department of Agriculture report on 43 common garden fruits and vegetables and found that almost half of the substances containing minerals important to good health had lost some nutritional value.

Davis said in a university news release that at first, his team didn't evaluate individual fruits and vegetables but found the nutritional declines in the plants as a group. "Considered as a group, we found that six out of 13 nutrients showed apparently reliable declines between 1950 and 1999," he said.

The nutrients Davis's team identified as losing at least some measurable value were protein, calcium, phosphorus, iron, riboflavin and ascorbic acid. The declines ranged from 6 percent for protein to 38 percent for riboflavin.

Specific Produce Identified as Losing Nutritional Value

Why did this happen? As best as Davis can determine, the nutritional value in some produce was diluted through faster methods major agro-farm companies employed to grow high-yield crops to meet consumer demand.

Davis continued studying what he termed the "genetic dilution effect" and was able to identify specific high-yield crops that had declines in nutrients.

Mother Earth News reported in its June/July 2009 edition that Davis had used the USDA report to find the following declines in nutritional value of broccoli:

According to U.S. Department of Agriculture (USDA) nutrient data, calcium content of broccoli which averaged 12.9 milligrams per gram of dry weight in 1950, had declined to only 4.4 mg/g dry weight in 2003

And in a study of much longer duration, Davis reported that in wheat and barley crops, protein concentrations declined by 30 to 50 percent between the years 1938 and 1990.....

Declining Nutrition of Fruits and Vegetables - www.cncahealth.com/explore/learn/nutrition-food/declining-nutrition-of-fruits-and-vegetables#.VG06qskmxzJ

[Master Kim]

Study suggests nutrient decline in garden crops over past 50 years

The University of Texas — A recent study of 43 garden crops led by a University of Texas at Austin biochemist suggests that their nutrient value has declined in recent decades while farmers have been planting crops designed to improve other traits.

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 agriculture practices are affecting food crops.....
Study suggests nutrient decline in garden crops over past 50 years - www.utexas.edu/news/2004/12/01/nr_chemistry