Subject: [SANET-MG] Declining Nutrient Content: JACN article

From: [email-masked]
Date: Mon, 20 Dec 2004 10:29:44 EST

I have not seen (or missed) a SANET posting about this article, which was  
schedule to appear in the December issue of the Journal of the American College  
of Nutrition. 

Karen Anderson
NOFA-NJ
 
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Study suggests nutrient decline in garden crops over past 50 years
Public release date: 1-Dec-2004
_http://www.eurekalert.org/pub_releases/2004-12/uota-ssn120104.php_ 
(http://www.eurekalert.org/pub_releases/2004-12/uota-ssn120104.php) 
 
Contact: Barbra Rodriguez
[email-masked] (mailto:[email-masked]) 
512-232-0675
University  of Texas at Austin
 
Study suggests nutrient decline in garden crops over past 50 years AUSTIN,  
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.
 
"We conclude that the most likely explanation was changes in cultivated  
varieties used today compared to 50 years ago," Davis said. "During those 50  
years, there have been intensive efforts to breed new varieties that have  greater 
yield, or resistance to pests, or adaptability to different climates.  But 
the dominant effort is for higher yields. Emerging evidence suggests that  when 
you select for yield, crops grow bigger and faster, but they don't  
necessarily have the ability to make or uptake nutrients at the same, faster  rate."
 
According to Davis, these results suggest a need for research into other  
important nutrients and foods that provide significant dietary calories, such as  
grains, legumes, meat, milk and eggs.
 
"Perhaps more worrisome would be declines in nutrients we could not study  
because they were not reported in 1950 -- magnesium, zinc, vitamin B-6, vitamin  
E and dietary fiber, not to mention phytochemicals," Davis said. "I hope our  
paper will encourage additional studies in which old and new crop varieties 
are  studied side-by-side and measured by modern methods."

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