GM Free Cymru

Crucial Paper 20:
GM Soy and reproductive effects in rats

Note from GM - Free Cymru:  This article needs careful examination -- it looks as if the intention of the authors was to find NO difference in the effects of consuming GM soy and organic soy.  Stanley Ewen has looked at this paper, however, and Jeffrey Smith reports his reaction as follows:

"Female rats fed GM soy for 15 months showed significant changes in their uterus and reproductive cycle, compared to rats fed organic soy or those raised without soy. Published in The Anatomical Record in 2009, this finding adds to the mounting body of evidence suggesting that GM foods contribute to reproductive disorders.

Unlike women whose menstrual cycle starts automatically at puberty, female rats need to be "inspired." Their (estrous) cycle conveniently kicks in only after being introduced to male rats. Since no males were present in this study, the females fed organic soy or no soy were appropriately untriggered (diestrus).  For some odd reason, however, those fed GM soy appeared to have their ovulation cycle in full gear.

Although the researchers did not perform a check on the estrous cycle directly, their microscopic analysis of ovaries and uterus tissue showed that the hormone-induced changes (i.e. early ovulation and formation of corpus luteum) were well underway. In addition, the lining of the uterus (endometriim) had more cells than normal and the glands were dilated. In simpler terms, according to senior UK pathologist Stanley Ewen, something in the GM soy diet was "wrecking the ovary and endometrium" of the rats."


The Impact of Dietary Organic and Transgenic Soy on the Reproductive System of Female Adult Rat

Flávia Bittencourt Brasil, LavíNia Leal Soares, Tatiane Silva Faria, Gilson Telles Boaventura, Francisco José Barcellos Sampaio, Cristiane Fonte Ramos,

The Anatomical Record: Advances in Integrative Anatomy and Evolutionary Biology Volume 292, Issue 4, pages 587-594, April 2009


The goal of this article was to compare the effects of a prolonged use of organic and transgenic soy on the lipid profile and ovary and uterus morphology. Wistar rats were fed three different diets from weaning until sacrifice at 15 months of age. The three diets were: casein-based diet control group (CG), organic soy-based diet group (OSG), or transgenic soy-based diet group (GMSG). There were no differences in food consumption or in the diet isoflavone components among the groups. Compared with the CG diet, both the OSG and GMSG diets were associated with significant reductions in body weight, serum triglycerides, and cholesterol (P < 0.05) (CG = 406 ± 23.1; 104.3 ± 13.2; 119.9 ± 7.3 GMSG = 368 ± 17.6; 60.3 ± 4.6; 83.3 ± 5.7 OSG = 389 ± 23.5; 72.3 ± 12.5; 95.5 ± 8.0, respectively). The volume density of endometrial glandular epithelium was greater in the GMSG group (29.5 ± 7.17, P < 0.001) when compared with the CG (18.5 ± 7.4) and OSG (20.3 ± 10.6) groups. The length density of endometrial glandular epithelium was shorter in both GMSG (567.6 ± 41.1) and OSG (514.8 ± 144.5) diets compared with the CG (P < 0.05) diet. GMSG also resulted in reduced follicle number and increased corpus luteum number compared to the OSG or CG diets (P < 0.05). In summary, both GMSG and OSG diets resulted in decreased body weight and lower serum triglyceride and cholesterol levels, and alterations in uterine and ovarian morphology were also observed. The prolonged use of soy-based diets and their relation to reproductive health warrants further investigation.

Anat Rec, 292:587-594, 2009. © 2009 Wiley-Liss, Inc.