American Chemical Society, 2003-03-04

 Fruits and veggies grown organically show significantly higher levels
of cancer-fighting antioxidants than conventionally grown foods,
according to a new study of corn, strawberries and marionberries. The
research suggests that pesticides and herbicides actually thwart the
production of phenolics chemicals that act as a plant's natural
defense and also happen to be good for our health. Fertilizers,
however, seem to boost the levels of anti-cancer compounds.

 The findings appear in the Feb. 26 print edition of the Journal of
Agricultural and Food Chemistry, a peer-reviewed journal of the
American Chemical Society, the world's largest scientific society. The
article was initially published Jan. 25 on the journal's Web site.

 Flavonoids are phenolic compounds that have potent antioxidant
activity. Many are produced in plants in response to environmental
stressors, such as insects or competing plants.

 "If an aphid is nibbling on a leaf, the plant produces phenolics to
defend itself," says Alyson Mitchell, Ph.D., a food scientist at the
University of California, Davis, and lead author of the paper. "Bitter
or harsh phenolics guard the plant against these pests."

 The need for these natural safeguards decreases with the use of
herbicides and pesticides in conventional agriculture. This decrease
is reflected in the total amount of antioxidants the plants produce.
"This helps explain why the level of antioxidants is so much higher in
organically grown food," Mitchell says. "By synthetically protecting
the produce from these pests, we decrease their need to produce
antioxidants. It suggests that maybe we are doing something to our
food inadvertently."

 Mitchell measured antioxidants found in corn, strawberries and a type
of blackberry called a marionberry. "We started with these three due
to plant availability," Mitchell explains, "but we intend to widen our
search to include tomatoes, peppers, broccoli and a variety of other
vegetables. We expect these results to be transferable to most

 The investigation compared the total antioxidants found in foods
grown organically (using no herbicides, pesticides or fertilizers) to
foods grown sustainably (in this study fertilizers but no herbicides
or pesticides were used) and conventionally (using synthetic chemicals
to protect the plants and increase yield).

 The results showed a significant increase in antioxidants in organic
and sustainably grown foods versus conventionally grown foods. The
levels of antioxidants in sustainably grown corn were 58.5 percent
higher than conventionally grown corn. Organically and sustainably
grown marionberries had approximately 50 percent more antioxidants
than conventionally grown berries. Sustainably and organically grown
strawberries showed about 19 percent more antioxidants than
conventionally grown strawberries.

 Antioxidant levels were highest overall in sustainably grown produce,
which indicates that a combination of organic and conventional
practices yields the highest levels of antioxidants. "This may reflect
the balance between adequate nutrition in the form of fertilizers and
external pest pressures because of the lack of pesticides and
herbicides," Mitchell explains.

 "Originally, the question was just really intriguing to me," says
Mitchell, whose research grew naturally from a personal interest in
organic foods. "I found that the higher level of antioxidants is
enough to have a significant impact on health and nutrition, and it's
definitely changed the way I think about my food."

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