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Studies: Winter 2004
Impaired Intestinal Development
Two studies carried out by nutrition professor Sharon Donovan at the
University of Illinois show that the soy isoflavone genistein, in amounts
present in commercial soy infant formula, may inhibit intestinal cell
growth in babies. The first, published in the Journal of Nutrition
(June 2004) was an in vitro study in which Donovan treated
intestinal cells in culture with genistein in the amount present in
soy infant formula and found that the cells "basically stopped
proliferating."
The second was an in vivo study using pigs, to appear in the
journal Pediatric Research, February 2005. Donovan fed one
group of piglets a regular cow’s milk-based formula while the
other groups got the formula supplemented with genistein at the level
found in soy formula. In the piglets fed genistein, the number of proliferating
cells in the intestine was 50 percent lower than in the piglets fed
cow’s milk formula alone. Concentrations of genistein in the piglets’
blood were similar to those of babies fed soy formula, so these data
may be applicable to human infants, the researchers said. Newborn pigs
are an excellent model for human infants because they have a similar
metabolism and physiology. The research indicated that genistein had
no effect on mature intestinal cells that were no longer proliferating,
but a very profound negative effect on the developing intestinal tract.
This research provides an explanation of the many reports we receive
of digestive problems in soy-fed infants.
Endocrine Disruption
Researcher Claude Hughes has headed several studies on the effects
of maternal exposure to soy isoflavones on the reproductive health of
the offspring. In his latest study, he found that treating pregnant
rats with genistein from gestational day 14 through weaning resulted
in perturbations in the uterine structure that could affect the reproductive
health of female offspring. The research suggests that "soy phytoestrogen
exposure during reproductive development may have long-term reproductive
health consequences (Exp Biol Med (Maywood) 2004 Jan;229(1):108-17).
We’ve said it before but it bears repeating: pregnant and nursing
women should not consume soy.
Sickly Sperm
Lorraine Anderson, a student of medicine at Queen’s University,
Belfast, Northern Ireland, has devoted several years of research to
the effect of soy isoflavones on markers of reproductive health. Her
most important discovery has to do with the effect of soy phytoestrogens
on sperm motility (www.qub.ac.uk/cm/og/lorraineandersonrp.html).
Sperm surrounded by seminal fluid containing isoflavones moves more
slowly. Some samples moved so sluggishly that they would have trouble
reaching and fertilizing an egg. Says Anderson, "It doesn’t
matter how many sperm a man’s got; if they can’t get from
A to B, then there’s little chance of reproduction."
Thyroid Troubles
A study carried out at the Department of Pediatrics at Northwestern
University Medical School looked at infants with congenital hypothyroidism
(Arch Dis Child. 2004 Nov;89(11):1077). Researchers found that
feeding soy formula to these infants caused a prolonged increase of
thyroid stimulating hormone (TSH) compared to infants fed non-soy formula.
In other words, it was much harder to normalize thyroid function in
the soy-fed infants.
Toxins + Soy = Trouble
Two groups of rats were exposed to environmental toxins on days 9-16
of gestation. One group was also exposed to the soy phytoestrogen genistein.
Researchers found only mild changes in the mammary glands of the rats
exposed to the toxins, but pronounced changes in those who got the toxins
plus the genistein. Said the researchers, "Collectively, our results
reveal that postnatal exposure to pharmacological levels of genistein
induces profound morphological changes in the mammary glands of female
rats
. . ." (Toxicol Sci. 2004 Jan;77(1):91-100).
The Whole Soy Story
It’s finally here! The Whole Soy Story by Kaayla T.
Daniel, PhD, looks at what the science says about the effects of soy
consumption on various aspects of human health--development, fertility,
thyroid function and even learning and behavior. Daniel’s conclusions
are ominous and this book is a must read for parents and grandparents
concerned about the health of their offspring. The book is available
online at wholesoystory.com and will be in the bookstores by April,
in time for National Soy Month.
Sidebar articles
Solae Wants More Time
In March, 2004, Solae, a joint venture of Dupont and Bunge, submitted
a petition to the FDA for a Soy Protein and Cancer Health Claim. On
April 14, the Weston A. Price Foundation submitted a rebuttal to the
Solae petition, urging the FDA to deny the company’s request.
Our 50-page response, prepared by Dr. Kaayla T. Daniel and posted at
westonaprice.org lists numerous
studies implicating soy protein as a contributor to cancers of the breast,
prostate and gastrointestinal tract.
The FDA has responded by allowing Solae more time, which Solae specifically
requested in response to our submission. The company also requested
a more watered down claim. We will again respond, urging that no claim
be allowed.
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