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  • From: "Tradingpost" <tradingpost@lobo.net>
  • To: livingontheland@lists.ibiblio.org
  • Subject: [Livingontheland] Eating Your Veggies: Not As Good For You?
  • Date: Thu, 19 Feb 2009 10:41:12 -0700


this was sent to us by an ag teacher at UNM.


Wednesday, Feb. 18, 2009
Eating Your Veggies: Not As Good For You?
By M.J. Stephey
http://www.time.com/time/printout/0,8816,1880145,00.html
Declining Fruit and Vegetable Nutrient Composition: What Is the Evidence?
By Donald R. Davis
Journal of HortScience; February 2009, 5 pp.

The Gist:

If the economy isn't grim enough for you, just check out the February issue
of the Journal of HortScience, which contains a report on the sorry state
of American fruits and veggies. Apparently produce in the U.S. not only
tastes worse than it did in your grandparents' days, it also contains fewer
nutrients — at least according to Donald R. Davis, a former research
associate with the Biochemical Institute at the University of Texas,
Austin. Davis claims the average vegetable found in today's supermarket is
anywhere from 5% to 40% lower in minerals (including magnesium, iron,
calcium and zinc) than those harvested just 50 years ago. (Read about
Americans' Incredible, Edible Front Lawns.)

Highlight Reel:

1. On the Difficulty of Comparing "Then" and "Now:" Davis is quick to note
that historical data can sometimes be misleading, if not altogether
inaccurate. Take early measurements of iron in foods: because scientists
failed to sufficiently remove clinging soil, iron levels appeared unusually
high in certain vegetables like spinach, (which gave rise to the myth that
it contained exorbitant amounts of the mineral — a myth further
propagated by the popular cartoon character, Popeye). Then again, good
historical data provides the only real-world evidence of changes in foods
over time, and such data does exist — one farm in Hertfordshire, England,
for example, has archived its wheat samples since 1843.

2. On the So-Called "Dilution Effect:" Today's vegetables might be larger,
but if you think that means they contain more nutrients, you'd be wrong.
Davis writes that jumbo-sized produce contains more "dry matter" than
anything else, which dilutes mineral concentrations. In other words, when
it comes to growing food, less is more. Scientific papers have cited one of
the first reports of this effect, a 1981 study by W.M. Jarrell and R.B.
Beverly in Advances in Agronomy, more than 180 times since its publication,
"suggesting that the effect is widely regarded as common knowledge." (See
pictures of fruit.)

Less studied, though, is the "genetic dillution effect," in which selective
breeding to increase crop yield has led to declines in protein, amino
acids, and as many as six minerals in one study of commercial broccoli
grown in 1996 and '97 in South Carolina. Because nearly 90% of dry matter
is carbohydrates, "when breeders select for high yield, they are, in
effect, selecting mostly for high carbohydrate with no assurance that
dozens of other nutrients and thousands of phytochemicals will all increase
in proportion to yield."

2. On the "Industrialization" of Agriculture: Thanks to the growing rise of
chemical fertilizers and pesticides, modern crops are being harvested
faster than ever before. But quick and early harvests mean the produce has
less time to absorb nutrients either from synthesis or the soil, and
minerals like potassium (the "K" in N-P-K fertilizers) often interfere with
a plant's ability to take up nutrients. Monoculture farming practices —
another hallmark of the Big Ag industry — have also led to soil-mineral
depletion, which, in turn, affects the nutrient content of crops.

The Lowdown:

If you're still not buying the whole "organic-is-better" argument, this
study might convince you otherwise. As Davis points out, more than three
billion people around the world suffer from malnourishment and yet,
ironically, efforts to increase food production have actually produced food
that is less nourishing. Fruits seem to be less affected by genetic and
environmental dilution, but one can't help but wonder how nutritionally
bankrupt veggies can be avoided. Supplementing them is problematic, too:
don't look to vitamin pills, as recent research indicates that those aren't
very helpful either.





  • [Livingontheland] Eating Your Veggies: Not As Good For You?, Tradingpost, 02/19/2009

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