81% of approved GMOs not studied for detailed health effects
A group of researchers set out to see how much evidence there is for the safety of crops containing the most common GM genes — for insect resistance and herbicide tolerance — for animals that eat them. They focused on histopathological investigations of the digestive tract in rats, since this would be the main target organ of any new toxic proteins produced by the GM process.
The researchers found that of 47 crop varieties approved by government regulators for animal or human consumption, there were peer-reviewed published studies for only 9. They could find no studies whatsoever for the other 38 approved varieties. This means that they could not find any published histopathology studies for 81% of approved GM crop varieties. What is more, the studies that were carried out were poorly conducted or reported.
The researchers concluded, “There is a lack of evidence to prove that these crop varieties are safe to eat.”
The study is a useful antidote to the recent review by former Monsanto scientist Alison Van Eenennaam, which claimed to show that over 100 billion animals had eaten GM feed with no ill effects.
1. Does eating GM crops harm the digestive tracts of rats? — Clear English summary
2. GM crops and the rat digestive tract: A critical review — Study abstract
1. Does eating GM crops harm the digestive tracts of rats?
A review of the scientific evidence
Clear English summary of paper by Dr Judy Carman
29 September 2014
This is a briefing about a new, peer-reviewed scientific paper titled: GM crops and the rat digestive tract: A critical review, by Irena Zdziarski, Dr John Edwards, Dr Judy Carman and Dr Julie Haynes*. The paper is a review done by researchers at the University of Adelaide, Flinders University and the Institute of Health and Environmental Research, all based in South Australia. The paper reviewed published studies where the health of rats was assessed after the rats were fed certain GM crops.
The most common types of GM crops are designed to do one of two things. The first type has a gene inserted into it (often the EPSPS gene) which causes the plant to make a new protein that allows the plant to survive being sprayed with a herbicide such as glyphosate. The most common of these are called Roundup Ready crops. The second type of crop has a gene inserted into it (often the cry1Ab or cry3Bb1 genes) so that the plant makes a new protein that is an insecticide, so that when an insect eats the plant, the insect also eats the new insecticidal protein, which results in the insect dying. GM crops are often now grown with two or more of these genes in them at the same time.