Are there unintended health effects of genetic engineering?

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Francis Thicke, agronomist and organic dairy farmer in Iowa, asks:

Do you think there are unanswered questions about the health effects of GE foods? I have heard GE critiques frequently contend that there have been very few feeding trials on the health effects of GE foods, and that in the feeding trials that have been done, the results have raised questions about the safety of GE foods.

For starters, what is your opinion on the case of Arpad Pusztai and the results of his GE potato feeding trials that abruptly got him fired. Has anyone ever replicated his experiment?

There are a lot of important things to discuss in relation to these questions. Since it is so important, I have a few guidelines to suggest. To make this discussion easy to follow, please be careful to use the “Reply” button next to each comment if you want to stay in the same line of conversation (there should be up to 10 levels of replies allowed), or scroll to the bottom to the comment box if you want to start a new line of conversation. If you are making a specific claim, please provide a source, preferably a reliable one such as a scientific journal, government or university website, etc. Lastly, please try to stay away from fallacies such as the ones listed here. If we stick with sound information, we’ll all learn a lot more from the discussion.

The  study that Dr. Thicke refers to is Effect of diets containing genetically modified potatoes expressing Galanthus nivalis lectin on rat small intestine (pdf) by Stanley W B Ewen and Arpad Pusztai. It appeared in the Lancet on 16 October 1999 after some controversy, alongside two commentaries: Genetically modified foods: “absurd” concern or welcome dialogue? (pdf) and Adequacy of methods for testing the safety of genetically modified foods (pdf).

ResearchBlogging.orgEwen SW, & Pusztai A (1999). Effect of diets containing genetically modified potatoes expressing Galanthus nivalis lectin on rat small intestine. Lancet, 354 (9187), 1353-4 PMID: 10533866

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Anastasia is Policy Director of Biology Fortified, Inc. and the Co-Executive Editor of the Biofortified Blog. She has a PhD in genetics with a minor in sustainable agriculture from Iowa State University. Her favorite produce is artichokes!