Healthy soil and sustainable growing

["TradingPostPaul" <tradingpost@riseup.net>]

(the last paragraph tells us that modern commercial varieties bred for high
yield have lost nutrition. I grow only heirlooms.)

Changes in USDA Food Composition Data for 43 Garden Crops, 1950 to 1999
Donald R. Davis, PhD, FACN, Melvin D. Epp, PhD and Hugh D. Riordan, MD
Journal of the American College of Nutrition, Vol. 23, No. 6, 669-682
(2004)
Published by the American College of Nutrition

http://www.jacn.org/cgi/content/full/23/6/669?maxtoshow=&HITS=10&hits
=10&RESULTFORMAT=&author1=donald+davis&andorexacttitle=and&andorexac
ttitleabs=and&andorexactfulltext=and&searchid=1&resourcetype=HWCIT

Bio-Communications Research Institute, Wichita, Kansas (D.R.D., M.D.E.,
H.D.R.)
Biochemical Institute, The University of Texas, Austin, Texas (D.R.D.)

Address reprint requests to: Donald R. Davis, PhD, Biochemical Institute,
The University of Texas, 1 University Station A5100, Austin, TX 78712-0163.
E-mail: d.r.davis@mail.utexas.edu


           ABSTRACT

Objectives: To evaluate possible changes in USDA nutrient content data for
43 garden crops between 1950 and 1999 and consider their potential causes.

Methods: We compare USDA nutrient content data published in 1950 and 1999
for 13 nutrients and water in 43 garden crops, mostly vegetables. After
adjusting for differences in moisture content, we calculate ratios of
nutrient contents, R (1999/1950), for each food and nutrient. To evaluate
the foods as a group, we calculate median and geometric mean R-values for
the 13 nutrients and water. To evaluate R-values for individual foods and
nutrients, with hypothetical confidence intervals, we use USDA’s standard
errors (SEs) of the 1999 values, from which we generate 2 estimates for the
SEs of the 1950 values.

Results: As a group, the 43 foods show apparent, statistically reliable
declines (R < 1) for 6 nutrients (protein, Ca, P, Fe, riboflavin and
ascorbic acid), but no statistically reliable changes for 7 other
nutrients. Declines in the medians range from 6% for protein to 38% for
riboflavin. When evaluated for individual foods and nutrients, R-values are
usually not distinguishable from 1 with current data. Depending on whether
we use low or high estimates of the 1950 SEs, respectively 33% or 20% of
the apparent R-values differ reliably from 1. Significantly, about 28% of
these R-values exceed 1.

Conclusions: We suggest that any real declines are generally most easily
explained by changes in cultivated varieties between 1950 and 1999, in
which there may be trade-offs between yield and nutrient content.