Guest
Commentary
Joan Dye Gussow, Ed.D,
Is Organic Food More Nutritious? And Is That the Right Question?
My interest in the nutritional value of organic as compared to conventional
foods began in the late 1960s, even before I was a nutritionist.
So my first piece of independent work as an experienced researcher
but a
beginning student in the nutrition field was an effort to examine the
widespread claim that modern agriculture has created mineral deficient soils.
My conclusion, after a lot of library research, was that soil contamination
with lead, mercury and especially cadmium because of the over use of some rock
based fertilizers was a more likely outcome than mineral deficiency.
It was around this time that I became acquainted with someone fairly
high up in
Rodale Press, the organization which had been at the forefront of organic
superiority claims. I took advantage of our meeting to press him for sources
regarding the Rodale claim that organically grown produce was superior
nutritionally. His response reassured me that there was not a great body of
evidence that I had missed: "I guess when, we were a small beleaguered band and
needed to make noise to get attention, we said a lot of things. I think the
real argument for organic is environmental."
By that time it was already clear to me that part of the problem in
proving or disproving the claims made for organic foods arose from the way in
which the studies were being done. They were always short term studies looking
at produce from one field treated "organically"(usually with a shot of manure)
and another field treated "conventionally." My fairly simple-minded
understanding at the time was that the basis of organic was to build up the
soil. Planting into any old ploughed up field meant there had not been time
for organic practices to build soil fertility, nor for the chemicals to "burn
up" (in the language of the time) the residual fertility in the conventional
plot. Moreover, I knew enough about plant physiology to know that the mineral
content of plants was largely dependent on the mineral content of the soils
where they were grown, and that most differences in vitamin content were likely
to be either genetic or caused by climate or other variables unrelated to
specific growing techniques.
Moreover, if organic produce was more nutritious, that is health promoting--not
merely more nutrient filled--that fact might well not be demonstrable by
comparing lists of familiar nutrients. This has become increasingly obvious
recently as an ever lengthening list of "non-nutrient" substances turn out to
be essential to long-term good health. If one wanted to test nutritive value,
I thought, the foods--organic and conventional--would need to be fed to someone
or something.
So when I learned in the 1970s that the British Soil Association had
been comparing conventional and organic growing for 30 years, I wrote to ask
whether they had ever fed the produce to animals. They replied that they had
done some animal feeding, but it was clear that they did not have the smoking
gun everyone was looking for: "It is difficult to produce scientifically
acceptable evidence to prove that food grown by organic methods has a higher
nutritional value than food grown by controlled chemical agriculture," their
General Secretary wrote. Then he added, "There is a fund of circumstantial
evidence and a great deal of emotional conviction (ital mine) about the
value of
organically grown food for the health of both humans and animals." More than 20
years later, that's still a pretty good statement of where things stand.
I have tried, in the interim, to keep abreast of efforts to answer the
question of whether organic food is superior, but I must confess that my
interest has flagged has a variety of often not very well designed studies have
reported a confusing welter of results. In 1982, a careful researcher named
Dietrich Knorr published a review of the literature until then (including the
European literature) in which he noted that many of the studies "lack adequate
design for sufficient comparisons, the most common problem being the
insufficient duration of the studies."
The studies he cited (of which there were nine) showed not consistent sensory
differences between organic and conventionally grown produce; and showed or did
not show an effect of differently grown wheats on the growth rate and/or
reproductive performance of rats, mice and/or rabbits. The most consistent
data related to higher levels of nitrate-nitrogen in conventionally grown
vegetables, and a tendency for organic produce--especially potatoes--to be less
watery and hence lose less weight in storage.
In 1992, Hornick published in the Journal of Alternative Agriculture a paper
titled "Factors affecting the nutritional quality of crops," in which she
pointed out that USDA's 1980 Report and Recommendations on Organic Faming had
found insufficient evidence to show organic produce nutritionally superior to
conventionally grown produce. This finding, she concluded, reflected once
again "the lack of scientifically sound and statistically valid data from
experiments with properly controlled variables." Sounds familiar, doesn't it?
Hornick's paper provides an excellent description of what can go wrong
and what needs controlling in any study that hopes to do a valid comparison of
organic and conventional crops. She also makes clear that showing an effect of
"soil cultural and management practices on the nutritional quality of crops" is
insufficient to prove organic more nutritious. It is also necessary to "assess
these practices on the bioavailability of food nutrients after ingestion by
humans and animals."
Lacking such careful studies, there is enough cumulative evidence, to
indicate--to those who wish to be convinced--that organic foods often have a
variety of qualities that shouldover the long term make them more
healthful--including lower levels of pesticide residue, lower levels of
nitrate-nitrogen, greater density, better flavor if they are property handled,
etc. But the available studies are conflicting enough and their results are
varied enough to convince anyone who isn't a fan of organic, that any
differences that can be demonstrated are not worth writing home about, and are
certainly not a reason to promote organic food.
Which leads me to two questions I think the organic industry needs to
answer. The first is: given the modern opportunities for what I have come to
call information pollution do you really want to hang your future on putting
out comparative numbers rather than focusing on the environmental reasons why
organic production is better for people? Numbers can and will be increasingly
untrustworthy as we enter more deeply into the virtual world of the Internet in
which factoids race about through the electrons, endlessly repeated among true
believers.
At least twice in the last few months people who knew of my skepticism
have urged me to read studies presumably showing the superiority of organic
produce. When I did so, one turned out to be irrelevant, the other invalid. As
Katherine DiMatteo [Executive Director of the Organic Trade Association] has
written, "How many times have we reached out and grabbed onto the newest
evidence--no matter how minor, poorly substantiated or altered--that organic
may be nutritionally better?"
My second question is: why would you want organic consumers to end up focused
on numbers that can so readily be modified to reflect nothing about the
original produce? A recent description of one very successful juice company
done for potential investors, notes their organic sourcing of fruits and
vegetables, their emphasis on "Nourishing the body whole," and a new juice
introduced in August of 1994 with women in mind. "The ingredients are fresh
apricot, apple, orange, cranberry and raspberry juices plus added calcium, iron
and B-vitamins."
When most people can (and do) tale vitamins and minerals in pills, and when it
is so easy to fortify everything with nutrients, shouldn't we hope that people
will choose organic foods on grounds more reliable than whether they contain a
little more carotene or zinc? Isn't the most important story that organic
production conserves natural resources, solves rather than creates
environmental problems, and reduces the pollution of air, water, soil,...and
food?
If the industry wants to get proof of nutritional superiority, you may be able
to do it. But someone will have to pay for well-designed long-term controlled
studies of a sort that have to my knowledge not yet been done. I'm not
personally convinced that such studies would be worth the money and effort it
would like to do them--not when there are so many other good reasons to support
organic production.
Joan Dye Gussow is Professor Emeritus of Nutrition and Education, Columbia
Teachers College. This article is adapted from her talk given at OFRF's Fall
1995 conference, Legal, Regulatory and Marketing Issues Facing the Organic
Products Industry, in Oakland California.
Organic Farming Research Foundation
P.O. Box 440, Santa Cruz, CA 95061
ph: (831) 426-6606 fax: (831) 426-6670
www.ofrf.org
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Joan Dye Gussow,
Ed.D,
Is Organic Food More
Nutritious? And Is That the Right Question?
My interest in the
nutritional value of organic as compared to conventional foods began in
the late 1960s, even before I was a nutritionist.
Rodale Press, the organization which had been at the forefront of organic
superiority claims. I took advantage of our meeting to press him
for sources regarding the Rodale claim that organically grown produce was
superior nutritionally. His response reassured me that there was not a
great body of evidence that I had missed: "I guess when, we were a
small beleaguered band and needed to make noise to get attention, we said
a lot of things. I think the real argument for organic is
environmental."
Moreover, if organic produce was more nutritious, that is health
promoting--not merely more nutrient filled--that fact might well not be
demonstrable by comparing lists of familiar nutrients. This has
become increasingly obvious recently as an ever lengthening list of
"non-nutrient" substances turn out to be essential to long-term
good health. If one wanted to test nutritive value, I thought, the
foods--organic and conventional--would need to be fed to someone or
something.
The studies he cited (of which there were nine) showed not consistent
sensory differences between organic and conventionally grown produce; and
showed or did not show an effect of differently grown wheats on the
growth rate and/or reproductive performance of rats, mice and/or
rabbits. The most consistent data related to higher levels of
nitrate-nitrogen in conventionally grown vegetables, and a tendency for
organic produce--especially potatoes--to be less watery and hence lose
less weight in storage.
In 1992, Hornick published in the Journal of Alternative
Agriculture a paper titled "Factors affecting the nutritional
quality of crops," in which she pointed out that USDA's 1980 Report
and Recommendations on Organic Faming had found insufficient evidence to
show organic produce nutritionally superior to conventionally grown
produce. This finding, she concluded, reflected once again
"the lack of scientifically sound and statistically valid data from
experiments with properly controlled variables." Sounds familiar,
doesn't it?
My second question is: why would you want organic consumers to end up
focused on numbers that can so readily be modified to reflect nothing
about the original produce? A recent description of one very
successful juice company done for potential investors, notes their
organic sourcing of fruits and vegetables, their emphasis on
"Nourishing the body whole," and a new juice introduced in
August of 1994 with women in mind. "The ingredients are fresh
apricot, apple, orange, cranberry and raspberry juices plus added
calcium, iron and B-vitamins."
When most people can (and do) tale vitamins and minerals in pills, and
when it is so easy to fortify everything with nutrients, shouldn't we
hope that people will choose organic foods on grounds more reliable than
whether they contain a little more carotene or zinc? Isn't the most
important story that organic production conserves natural resources,
solves rather than creates environmental problems, and reduces the
pollution of air, water, soil,...and food?
If the industry wants to get proof of nutritional superiority, you may be
able to do it. But someone will have to pay for well-designed long-term
controlled studies of a sort that have to my knowledge not yet been
done. I'm not personally convinced that such studies would be worth
the money and effort it would like to do them--not when there are so many
other good reasons to support organic production.
Joan Dye Gussow is Professor Emeritus of Nutrition and Education,
Columbia Teachers College. This article is adapted from her talk given at
OFRF's Fall 1995 conference, Legal, Regulatory and Marketing Issues
Facing the Organic Products Industry, in Oakland California.
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