DallasNews: Corn fungal toxin & neural tube defects

David Kendra dkendra at mr.net
Tue Mar 6 17:17:05 EST 2001


"Gary Greenberg" <Gary.Greenberg at Duke.edu> wrote in message
news:3AA383F4.B94D3E27 at Duke.edu...
> Corn toxin examined in border birth defects

This title is very misleading and totally inaccurate.  The toxin in
question, fumonisin, is produced by several species of Fusarium (a fungus)
which is pathogenic to corn and several other crop species.

dk

>
> Diet may have put Hispanics at risk
>
> 03/04/2001
>
> By Laura Beil / The Dallas Morning News
>
> http://www.dallasnews.com/science/health/302523_toxiccorn_met04.html
>
> [Mod: Please visit the website for this article, which looks at every
> useful aspect, including dose, mechanism, time variability and
> interactive risks - G)
>
> The nurses at Valley Regional Medical Center in Brownsville sensed
> something more than a horrible coincidence. Two babies born the same day
> in April 1991 had brains that were stunted or missing, a rare defect
> that usually strikes only three or four births in 10,000.
>
> ...
>
> State and national investigators would eventually find that Brownsville
> had an astonishingly high rate of anencephaly, as the condition is
> called. From 1989 through 1991, 32 women in this town of 130,000 carried
> anencephalic babies. Many of the children died within hours, and all
> within days, of birth.
>
> Then, in 1992, the anencephaly rate ebbed as unexpectedly as it had
> risen.
>
> Still searching for a cause, many experts keep circling back to one of
> the few explanations for an epidemic that can come and go on its own: a
> natural poison that crept in and out of the food supply. Disease
> investigators have focused on a common toxin found in corn, a mainstay
> of a traditional Mexican-American diet. If this toxin is indeed
> responsible for the birth defects that stalked the Lower Rio Grande
> Valley - and no one has yet concluded that it is - then Texas health
> officials worry about other effects in Hispanics. In addition to birth
> defects, the chemical may increase the risk for esophageal and liver
> cancer.
>
> The outbreak of 1991 remains unsolved. From the beginning, many
> residents suspected the pesticides that armor nearby fields of cotton
> and sorghum. Others blamed the chemicals that waft from industries along
> the Rio Grande. Some parents of affected infants even shared a $17
> million settlement from more than 80 maquiladoras - U.S. factories
> hugging the Mexican side of the river - in 1995.
>
> But now, state health officials wonder whether the culprit was not
> man-made, but a natural fungus that can cling to corn. The fungus makes
> a toxin, called fumonisin, unknown to science until 1988.
>
> ...
>
> Given fumonisin's potential to cause disease, a United Nations committee
> will soon release its first report recommending a daily limit on human
> exposure to the toxin. Last summer, the U.S. Food and Drug
> Administration announced possible guidelines for the maximum amount of
> fumonisin in corn intended for human food. The agency recommends no more
> than 4 parts per million for masa and similar corn products.
>
> But the FDA number, state officials argued in a three-page response, may
> be too high for those who depend on corn for their daily bread. "There
> is clear evidence," state officials warned, "that fumonisins are
> carcinogenic in some animal species and sufficient evidence indicating
> that these compounds may be able to affect the neural development of the
> fetus."
>
> ...
>
>
> Fumonisin (pronounced few-MAHN-i-sin) is spit out by the mold Fusarium
> as part of its chemical defense system. For decades, farmers and
> ranchers have known that animals can fall seriously ill if they eat corn
> that has been coated with Fusarium, even if the kernels later seem
> clean. People in parts of the world with high Fusarium growth, most
> notably the Transkei region of South Africa, have high rates of
> esophageal cancer.
>
> But it wasn't until 1988, when South African scientists first described
> fumonisin, that anyone knew exactly why the mold was dangerous.
>
> One of the more peculiar traits of fumonisin is its ability to cause
> vastly different diseases in different animal species. Pigs that eat
> fumonisin-contaminated corn can develop pulmonary edema, a condition in
> which their lungs fill with fluid. The most sensitive animals appear to
> be horses, which get a crippling brain disease called
> leukoencephalomalacia.
>
> In humans, hints of the esophageal and liver cancer risks come from
> studies in rats, and from parts of the world - such as the Transkei and
> certain areas of China - with frequent fumonisin contamination of corn.
> Health officials note that these regions also have high rates of the
> same birth defects that appeared in the Rio Grande Valley. But this kind
> of research doesn't address the possibility of a coincidence.
>
> Possible fetal effects
>
> Anencephaly, which befell Brownsville's babies, is one of a cluster of
> abnormalities called neural tube defects. The most common is spina
> bifida. The defects occur soon after conception, at a time when a woman
> wouldn't even know she is pregnant. They happen when the cells of the
> embryo that will create the central nervous system don't wrap around
> themselves and form a tube during development. Sufficient levels of
> folic acid, a B vitamin, will protect against neural tube defects.
>
> In 1997, researcher Victoria Stevens of Emory University in Atlanta
> offered a possible connection between fumonisin and folic acid. In
> test-tube experiments, she found that fumonisin interfered with a cell's
> ability to absorb the vitamin. If this is true in the womb, then
> fumonisin might starve a developing embryo of its protection.
>
> much more at website
>
> --
> Gary N. Greenberg, MD MPH    Sysop / Moderator Occ-Env-Med-L MailList
> gary.greenberg at duke.edu     Duke Occupat, Environ, Int & Fam Medicine
> OEM-L Maillist Website:                      http://occhealthnews.com
>
>
> ---
>







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