10/5/2010

GM Food, Hamsters and Junior High Science Fair Science

Filed under: — Bravus @ 7:13 am

Someone posted this link in a discussion forum, using the same post title as the title of the article:

http://www.salem-news.com/articles/april262010/gm-food-as.php

Now, there are a few warning signs in the ‘newspaper’ article itself: the fact that it cites 3 sources of information, but two of them are earlier articles by the same author on the same subject and one is a book review on a similar obscure site. The fact that none of the citations is to a published scientific paper. The fact that this ‘newspaper’ site has a Paypal link on the top right hand corner asking for donations is also a bit of an alarm bell in relation to its credibility.

But leave those things aside for a bit, and look at the actual research study reported. There are several serious problems with it:

  1. It has not yet been published, anywhere (I looked). That means it has never undergone peer review which, imperfect as it sometimes is, is the gold standard in science. No-one outside the research team has checked how well the study was done and whether the evidence actually supports the claims made.
  2. The study uses very small samples: this more detailed report shows that each group of hamsters (there were 4 treatment groups, from zero GM food to small, medium and large amounts of GM food) contained only 5 pairs of hamsters, a total of 10 individuals. There were 3 generations in total in the study, a total of only 140 animals. In the ‘lots of GM food’ group from which the infertility was reported there would have been only about 30-35 animals total: that’s a very small sample from which to make broad claims. And it’s entirely possible that some of the infertility could have resulted from a genetic issue with some of the original 5 pairs chosen, that was spread by the inbreeding, rather than from the GM foods.
  3. The study has not yet been replicated in another lab elsewhere.

The most important issue, though, is that correlation has been treated as causation. That is, there is a correlation between eating the GM food and infertility, but since there is no specific science in the paper on a causal mechanism – say ‘genes from the GM food are transferring into bacteria in the gut of the hamsters and then in some way into the genome of the hamsters themselves’ – all that’s there is a correlation. That’s why I referred to it as ‘junior high science fair science’. I’ve judged a few science fairs in my time, and it’s perfectly valid for a Year 8 student to do a study of ‘rock music versus classical music: effect on plant growth’ and make claims about the correlations observed. But they’re not doing ‘real science’ because they do not have a causal mechanism.

And because there are always plenty of confounding variables. Just off the top of my head, one of the common genetic modifications made to food crops is to make the plants immune to the effects of glyphosate (‘Round Up’) pesticides. This means the farmer can spray the entire field with the pesticide, and the crop won’t die but the weeds will. It’s entirely possible that what caused the observed infertility in the hamsters (if, indeed, it’s a real effect and not an artefact of the small study size or some other factor) was higher pesticide residues in their food, rather than the genetic modifications directly. That’s an important issue, but it’s one that can be dealt with… and it’s a different issue than genetic modification more broadly.

The problem with a study without a causal theory being tested is that it doesn’t appropriately direct our attention to solutions – and to directions for further research.

My choosing to point out these scientific problems has been misunderstood in the discussion on the forum as being ‘going in to bat for GM’ and ‘supporting Monsanto’ – and it’s neither of those things. I do think there are real and serious issues and concerns around the use of genetically modified plants in foods. But you don’t address real and serious issues by doing crappy science.

3 responses to “GM Food, Hamsters and Junior High Science Fair Science”

  1. Claudia says:

    You might also have mentioned that Monsanto and other GMO companies use end-user agreements to prohibit scientists from doing research on their products, which is why so little research exists. See this article “Do Seed Companies Control GM Crop Research? Scientists must ask corporations for permission before publishing independent research on genetically modified crops. That restriction must end” at Scientific American: http://www.scientificamerican.com/article.cfm?id=do-seed-companies-control-gm-crop-research

  2. Bravus says:

    Excellent point, and thanks very much for the link.

  3. Doctor Crankenstein says:

    Seems to me like he made every single mistake in the book. Newspapers worry me because they have a false sense of authority that people fall for all too readily.

    We went through a very similar article on the same topic in my undergrad statistics course. It’s quite hilarious watching a statistics lecturer tearing a journalist and his work to shreds.

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