Western Farm Press
Oct
27, 2004 9:12 AM
By
Bruce Chassy and Drew Kershen
In
the early 1990s, Hispanic women in the Rio Grande Valley of Texas gave birth to
babies with neural tube defects (NTDs) at a rate of 33 per 10,000 live births,
approximately six times the U.S. national average for non-Hispanic women.
Neural tube defects include spina bifida, hydrocephalus, and anencephaly.
Most
unborn children affected by NTDs do not even survive to birth, and those who do
are usually severely disabled. One hundred eighty-four Mexican-American women
and their babies suffered these devastating conditions during the early 1990s.
The
precise cause for the increased rate of NTDs in Texas remained a mystery until
recent research shed light on a surprising cause. Studies from China,
Guatemala, South Africa, and the United States show that a clear link exists
between diets containing unprocessed corn (known as maize in most of the world)
and NTDs. Unprocessed corn is found in tortillas and other products that
contain whole ground corn. Research (Acevedo, 2004) in Guatemala showed that in
four rural departments the children of women who ate unprocessed corn as a
significant part of their diet had a rate of NTDs (34.29 per 10,0000 live
births) at least six times the world rate.
What
connection could exist between unprocessed corn in the diet and children being
born with NTDs? Fumonisin, a deadly mycotoxin found in unprocessed corn is the
likely culprit according to research published in the Journal of Nutrition
(Marasas, April 2004). At the time that the Hispanic women of the Rio Grande
valley suffered the high rate of NTDs in their babies, the fumonisin level in
corn in the Rio Grande Valley was two to three times the normal level. These
women also reported much higher dietary consumption of homemade tortillas
prepared from unprocessed corn. Mycotoxins such as fumonisin are highly toxic
chemicals that are produced by molds and fungi. When corn is attacked by
insects a mold called Fusarium can grow at the site of insect damage and
produce fumonisin. Poor storage conditions can promote post-harvest growth of
molds on grain as well.
Blocks
folic acid
The
April 2004 research also made another important connection. Researchers learned
that fumonisin interferes with the cellular uptake of folic acid. Folic acid in
the diet, provided either directly from the foods eaten or through food
fortification and dietary supplements, is known to reduce the incidence of NTDs
in developing fetuses. Because fumonisin prevents the folic acid from being
absorbed by cells, women eating a diet of unprocessed corn contaminated with
fumonisin are at higher risk of giving birth to babies with NTDs even when
their diet contains the adequate amount of folic acid.
It
turns out that there is a way to limit toxic mold infestation in corn.
Researchers in Argentina, France, Italy, Spain, Turkey, and the United States
have clearly established that planting corn seeds genetically engineered to be
resistant to corn borers and similar insect pests results in the harvesting of
corn with much lower levels of fumonisin. The insect protected corn varieties
contain a protein that is found in a common soil bacterium called Bacillus
thuringiensis. In nature, this bacteria kills certain insect larvae but is
harmless to all other insect species, as well as humans and animals. Bt
preparations have been safely used for years in agriculture and are one of few
insect control methods used in organic agriculture. Using this knowledge, scientists
engineered corn that could produce the protein in the hopes of making
insect-protected corn plants. This genetically improved corn, dubbed Bt corn,
usually has drastically lower levels of fumonisin. It is not unusual for Bt
corn to have one-tenth to one-twentieth the amount of fumonisin that is found
on organic and conventional corn varieties.
The
U.S. Food and Drug Administration and the UK Food Safety Agency have
established guidance levels for recommended maximum fumonisin levels in food
and feed products made from corn. Even before the connection of fumonisin with
NTDs, food safety agencies recognized fumonisin as a highly toxic carcinogen.
Although highly processed cornstarch and corn oil are unlikely to be
contaminated with fumonisin, unprocessed corn or lightly processed corn (e.g.,
cornmeal) can have fumonisin levels that exceed recommended levels.
Cornmeal
tests
The
UK Food Safety Agency tested six organic cornmeal products and 20 conventional
cornmeal products for fumonisin contamination in September 2003. The six
organic cornmeals had fumonisin levels nine to 40 times the recommended levels
for human health. All six organic cornmeal products were voluntarily withdrawn
from grocery stores.
Genetically
improved Bt corn kernels are less often damaged by insects, greatly reducing
the chance of fumonisin contamination and its harmful effect. This health
benefit adds to the benefits that Bt corn has already brought to farmers and
consumers. Farmers have found that Bt corn improves yields and lowers their
labor costs. Bt corn also reduces pesticide use. Improved yields and reduced
costs mean grain prices are kept low.
Require
Bt corn?
Perhaps
faced with results like these, government regulators around the world should
require farmers to plant Bt corn. Unfortunately, farmers are often discouraged
from planting Bt corn. It is no secret that opponents of agricultural
biotechnology have slandered transgenic crops. These crops have passed rigorous
safety reviews by government regulatory agencies in many nations, including the
U.S. Environmental Protection Agency, the Food and Drug Administration, and the
Department of Agriculture experts say transgenic crops are safe but opponents
ignore the scientific facts and place scare stories in the media here and abroad.
Understandably,
some consumers respond to these scary, inaccurate claims by avoiding foods
containing transgenic crops like Bt corn. Some politicians respond by placing
inappropriate barriers to the adoption of these crops. The problem with these fright
reactions is that by diverting attention from the real risks in our food supply
(such as fumonisin in corn), our society suffers real damage and losses that
could and should be avoided. Women of child-bearing years may be hoping to eat
a healthier diet by selecting organic corn when in fact, the transgenic Bt corn
would be a healthier and less expensive choice, assuming they are allowed the
choice. Women of child-bearing years should not be forced by opponents of Bt
corn into a higher risk of bearing a child with an NTD. As Izelle Theunissen of
the Medical Research Council of South Africa has written, "So despite the
current discussions surrounding GM foods, it appears that Bt maize hybrids
could play a major role in lowering fumonisin levels in maize products, which
should ultimately enhance the quality and safety of maize for animal and human
consumption, particularly in the African context."
Ignoring
major risks
While
opponents of transgenic crops force our attention and our research dollars to
over-regulate transgenic crops, are we ignoring the major risks associated with
food? We know that major risks associated with food in the United States are
obesity, poor nutritional quality of our diets, the possible presence of
organisms that could cause illness, and the unrecognized presence of natural
toxins such as fumonisin.
While
many are convinced that organic food is healthier, it is no more nutritious
than conventional food. As shown by the recall of fumonisin-contaminated
organic corn meals, organic food, at times, may be less safe. Organic food is
not the answer to known food risks.
Perhaps
one recourse for harm done by irresponsible opposition to transgenic crops will
be a lawsuit against producers and manufacturers of fumonisin-laden corn products.
Will our courtrooms be the place that distinguishes the Bt corn science fiction
from fact?
(Bruce
Chassy is professor of Food Microbiology and Nutritional Sciences and executive
associate director of the Biotechnology Center, University of Illinois Urbana-Champaign;
Drew Kershen is Earl Sneed Centennial professor of law, University of Oklahoma
College of Law, Norman, Okla.)