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New study shows that animals are seriously harmed by eating GM crops

Wednesday 12 June 2013 – Press release from the authors of the study.

A ground breaking new study [1] shows that pigs were harmed by the consumption of feed containing genetically modified (GM) crops.

The research results were striking and statistically significant. GM-fed females had on average a 25% heavier uterus than non-GM-fed females, a possible indicator of disease that requires further investigation.

Also the level of severe inflammation in stomachs was markedly higher in pigs fed on the GM diet. Male pigs were more strongly affected. While female pigs were 2.2 times more likely to get severe stomach inflammation when on the GM diet, males were 4 times more likely.

Lead researcher Dr Judy Carman, adjunct associate professor at Flinders University, Adelaide, Australia,[2] said: “Our findings are noteworthy for several reasons. First, we found these results in real on-farm conditions, not in a laboratory, but with the added benefit of strict scientific controls that are not normally present on farms.

“Second, we used pigs. Pigs with these health problems end up in our food supply. We eat them.

“Third, pigs have a similar digestive system to people, so we need to investigate if people are also getting digestive problems from eating GM crops.

“Fourth, we found these adverse effects when we fed the animals a mixture of crops containing three GM genes and the GM proteins that these genes produce. Yet no food regulator anywhere in the world requires a safety assessment for the possible toxic effects of mixtures. Regulators simply assume that they can’t happen.


The new study lends scientific credibility to anecdotal evidence from farmers and veterinarians, who have for some years reported reproductive and digestive problems in pigs fed on a diet containing GM soy and corn.[3]

Iowa-based farmer as well as crop and livestock advisor Howard Vlieger, one of the coordinators of the study, said: “For as long as GM crops have been in the feed supply, we have seen increasing digestive and reproductive problems in animals. Now it is scientifically documented.


“In some cases, animals eating GM crops are very aggressive. This is not surprising, given the scale of stomach irritation and inflammation now documented. I have seen no financial benefit to farmers who feed GM crops to their animals.”

The research was conducted by collaborating investigators from two continents and published in the peer-reviewed Journal of Organic Systems. The feeding study lasted more than five months, the normal commercial lifespan for a pig, and was conducted in the US. The pigs were slaughtered at the usual slaughter age of over 5 months, after eating the diets for their entire commercial lifespan.

Find a clear summary of the study here:

Find the full paper here:

Website with full information on Dr Judy Carman’s work:

Study details

168 newly-weaned pigs in a commercial piggery were fed either a typical diet incorporating GM soy and corn, or else (in the control group) an equivalent non-GM diet. The pigs were reared under identical housing and feeding conditions. They were slaughtered over 5 months later, at the usual slaughter age, after eating the diets for their entire commercial lifespan. They were then autopsied by qualified veterinarians who worked “blind” – they were not informed which pigs were fed on the GM diet and which were from the control group.

The GMO feed mix was a commonly used mix. The GM and non-GM diets contained the same amount of soy and corn, except that the GM diet contained a mixture of three GM genes and their protein products, while the control (non-GM) diet had equivalent non-GM ingredients. Of the three GM proteins in the GM diet, one made a crop resistant to being sprayed with the herbicide Roundup, while two were insecticides.


Dr Judy Carman, Adelaide, Australia

To phone within Australia: 08 8332 7927, mobile phone 0408 480 944.

To phone outside of Australia: +61 8 8332 7927, mobile phone +61 408 480 944.


Mr Howard Vlieger, Maurice, Iowa

To phone within the US: 712 567 4151, cell phone 712 441 3911.

To phone outside of the US: +1 712 567 4151, cell phone +1 712 441 3911.




2. BSc (Hons) PhD MPH MPHAA; Epidemiologist and Biochemist; Director, Institute of Health and Environmental Research, Adelaide, Australia; Adjunct Associate Professor, Health and the Environment, School of the Environment, Adelaide, Australia

3. For example: