August 30, 2015
Terry Link is an occasional reader of the Thornapple Blog who never posts comments, but he will occasionally send an e-mail or make a comment when I see him in person. This week he passed along a link to an article by Sheldon Krimsky that has just been published in Science, Technology and Human Values. Shelly uses an analysis of two key case studies to argue against the claim that there is a strong and wide scientific consensus about the safety of genetically engineered food crops, or GMOs. Now, I can’t possibly say much about what those are and stay within my self-imposed word limit, so I’m just going to assume that everyone knows what Shelly is talking about and steam right on ahead. I’m guessing that Terry passed this along mainly because he knows I’m interested in GMOs, but I suspect that he is especially impressed by peer-reviewed research that gives us some reason to question the boosterism that we hear from many scientists—including many from MSU.
As it happens, I was one of the anonymous peer reviewers for this article. Ooops! I guess that I just blew my anonymity! Lest blog readers question my own ethics for revealing this, I’ll say that there is a weaker compunction against maintaining confidentiality with respect to papers that successfully negotiate the peer review process than for those that don’t. Journal editors shouldn’t reveal the identity of reviewers in any case, and they might prefer that reviewers themselves abstain from such disclosures as a way to protect the overall integrity of the process. But I’m coming out, anyway. If there is anyone out there who wants to take a swipe at the “idiots” who recommended that this piece be published, now you know where to come.
This is not to say that Shelly and I are in lock-step agreement about the two cases that he discusses. I do think that the article successfully shows that there is substantial disagreement within the scientific community about how these dissenters are treated. I agree totally with the part of his paper that criticizes the treatment given to Arpad Pusztai in the 1980s and to Gils-Eric Seralini more recently after both announced results from preliminary toxicological studies that some view as evidence for the riskiness of eating GMOs. Shelly also thinks that a) the studies themselves and b) the knee-jerk over-the-top defensiveness of mainstream science provide reasons to doubt the safety of GMOs. I disagree flatly on both points, though I have myself argued (in my book From Field to Fork: Food Ethics for Everyone) that drawing the inference from b) is perfectly reasonable. You’ll have to lay out the twenty-five bucks or make a trip to your library to get my views on this latter point, because I just don’t have the energy to go over that point again.
What I would have said on point a) if I had been writing this paper is that the science community has done an exceedingly poor job of explaining why they did not interpret Pusztai’s and Seralini’s results as evidence for an unacceptable risk. If I were inclined to be forgiving, I would note that explaining this is actually kind of hard. It couldn’t be done in a single entry of the Thornapple Blog, for sure. Doing a decent job drags you into thinking about what “unacceptable risk” means in the context of food safety. John Kreb’s little book Food: A Very Short Introduction explains that many foods contain natural toxicants that would prevent them from being approved if the substances had been added artificially. Potatoes are his example. It’s not unusual for potato breeders who are just doing ordinary cross breeding to accidently activate those toxicants, creating a potato that will make you very sick. It may be significant that Pusztai was testing a particular potato variety that had been genetically engineered. It may well have had some nasty bits in it, but Pusztai had no reason to think that they got there as a result of the genetic engineering.
Seralini was replicating an experiment described in published literature that is designed to test for “acute toxicity”—something that makes you sick right away. It’s what we might normally call “poison”. He didn’t find anything, but decided to extend the experiment for a longer time period than would normally be used for testing acute toxicity. This is not standard toxicological practice. The idea is that you would already be sick or dead, so why drag things out? Lo and behold, his rats started to develop tumors. What Shelly doesn’t tell you in his article is that the rats Seralini was using are considered to be good models for testing acute toxicity, but not for long term studies because they are known to have a genetic tendency to develop tumors as they get older. Whoops!
What’s amazing and depressing to me is that you can plow through many pages of tedious peer reviewed literature, not to mention “letters to the editor” without having either of these points explained to you. That, I think, is a problem in food ethics.
Paul B. Thompson is the W.K. Kellogg Professor of Agricultural, Food and Community Ethics at Michigan State University