The Sanet archives contain a number of posts relating to the
nutritional quality of organic foods.
In addition to references previously posted, here are three more
sources:
1.
"The Healing Power of Minerals, Special Nutrients and Trace Elements"
by Paul Bergner (1997, Prima Publishing, Rocklin, CA) includes USDA
figures that show a decline in mineral and vitamin content of several
fruits and vegetables between 1914, 1963, and 1992. Table 1 is a
summary of mineral decreases in fruits and vegetables over a 30-year
period, adapted from Bergner's book.
Table 1. Average changes in the mineral content of some fruits and
vegetables*, 1963-1992
Mineral Average % Change
Calcium -29.82
Iron -32.00
Magnesium -21.08
Phosphorus -11.09
Potassium -6.48
* Fruits and vegetables measured: oranges, apples, bananas,
carrots, potatoes, corn, tomatoes, celery, romaine lettuce, broccoli,
iceberg lettuce, collard greens, and chard
2.
In England, Anne Marie-Mayer compared food composition over a 50-year
period using data from the UK Ministry of Agriculture, Fisheries and
Food (MAFF). Her study, "Historical Changes in the Mineral
Content of Fruits and Vegetables" was presented at the Agricultural
Production and Nutrition conference held at Tufts University School of
Nutrition Science and Policy on March 19-21, 1997.
Table 2, adapted from Marie-Mayer's paper, summarizes the average
ratio of nutrient content and dry matter of 20 vegetables and 20
fruits. A ratio of 0.81 for Ca, for example, means that over an
approximately 50-year period the average content of calcium in
vegetables has declined to 81% of the original level.
Table 2. Average ratio of mineral content and dry matter (new/old)
for vegetables and 20 fruits*
Ca Mg Fe Cu Na K
P D.M.
Vegetable ratio 0.81* 0.65* 0.78 0.19* 0.57* 0.86 0.94
0.97
Fruit ratio 1.00 0.89* 0.68* 0.64* 0.90 0.80*
0.99 0.91
The symbol * indicates a statistical difference
3.
In 1997 an extensive literature review was published:
"A comparison of organically and conventionally grown foods --
results of a review of the relevant literature" by Katrin
Woese, Dirk Lange, Christian Boess, and Klaus Werner Bogl.
1997. J. Sci. Food Agric. Vol. 74, 281-293.
The authors are with:
Federal Institute for Health Protection of Consumers and
Veterinary Medicine, Division 2, Chemistry and Technology
of Foods and Commodities, PO Box 330013, D-14191, Berlin,
Germany.
The review summarizes and evaluates the results of more than 150
investigations (published between 1926 and 1994) comparing the
quality of conventionally and organically produced food, or of foods
produced by different fertilization systems.
The review is particularly noteworthy to those of us readers here in
the United States, because it looks like better than 90% of the
citations are from German-language journals and literature.
This article does a good job of addressing the parameters used
to evaluate differences item by item.
One passage worth noting:
"Only the more or less correlative results of the feed selection
tests permit a general conclusion: animals distinguish between the
foods on offer from the various agricultural systems and almost
exclusively prefer organic produce."
=============================================
As an aside, this is what Dr. William Albrecht emphasized in his work
as a soil scientist at the University of Missouri; i.e., animal
feeding trials to ascertain the true quality of feedstuffs, writing:
"cows are capable chemists"
"as a chemist by experience and survival, not by academic training,
the cow led the nomad over fertile soils"
"we need to start observing and judging the cow as she is a chemist
on the hoof guiding her own nutrition"
==============================================
Other findings:
*Lower nitrates in organically produced or fertilised vegetables.
*Lower pesticide residues in organic fruit and vegetables
*Higher dry matter content in organic products
*Feed experiments showed animals preferentially selected organic
produce, but where fertility parameters and rearing performance were
determined the results were contradictory
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