Study on GMO corn requires a non-GMO grain of salt
The Daily Mail is a British tabloid in the classic tradition of tabloids: sensationalized, eager to entertain, shallow. Here’s an example headline it ran today: “Michelle thought diet pills could help her drop a dress size. Now she’s got just ten years to live.” I mean, that’s a pretty solid headline right there. Clicking through, the story is a lot less salacious — anecdotal experiences are prominent, while scientific evidence is mostly used as filler. A good reminder to take what you read in the Daily Mail with a grain of salt.
Here’s another one of its headlines, this time from yesterday: “Cancer row over GM foods as study says it did THIS to rats… and can cause organ damage and early death in humans.” The article is paired with truly grotesque photos of tumor-swollen rats, and a shot of a protestor dressed as the grim reaper in a field of corn.
Let’s let Reuters describe the research behind this story.
Rats fed a lifetime diet of Monsanto’s genetically modified corn or exposed to its top-selling weedkiller Roundup suffered tumours and multiple organ damage, according to a French study published on Wednesday. …
Gilles-Eric Seralini of the University of Caen and colleagues said rats fed on a diet containing NK603 — a seed variety made tolerant to dousings of Roundup — or given water containing Roundup at levels permitted in the United States died earlier than those on a standard diet.
The animals on the GM diet suffered mammary tumours, as well as severe liver and kidney damage.
The researchers said 50 percent of males and 70 percent of females died prematurely, compared with only 30 percent and 20 percent in the control group.
Wow, right? Yeah, the Daily Mail put a powerful headline on the report, but this time it’s clearly warranted!
Except for what’s hidden behind that ellipsis up there.
Although the lead researcher’s past record as a critic of the industry may make other experts wary of drawing hasty conclusions, the finding will stoke controversy about the safety of GM crops.
In an unusual move, the research group did not allow reporters to seek outside comment on their paper before its publication in the peer-reviewed journal Food and Chemical Toxicology and presentation at a news conference in London.
Scientists without skin in the game were quick to point out other questions about the study.
Are the findings reliable?
There is little to suggest they are. …
But didn’t the treated rats get sicker than the untreated rats?
Some did, but that’s not the full story. It wasn’t that rats fed GM maize or herbicide got tumours, and the control rats did not. Five of the 20 control rats — 25 per cent — got tumours and died, while 60 per cent in “some test groups” that ate GM maize died. Some other test groups, however, were healthier than the controls.
It goes on. And there are other overviews of questions raised about the study.
My point is this: It is totally appropriate to be skeptical of genetically modified organisms. It is completely fair to choose not to incorporate GMOs into your life — and to work to make sure they’re labeled so you can avoid them. But it is critical that you maintain your skepticism around topics that fit your existing beliefs. You might be familiar with the idea of “confirmation bias,” the notion that we seek out evidence to support what we already believe. If you read the two Daily Mail headlines that started this article and rolled your eyes at the first one but were intrigued by the second one — that’s a touch of confirmation bias. Particularly if you’re familiar with the Daily Mail’s journalistic reputation.
Two last notes. The first: Confirmation bias affects not only what we choose to accept, but also what we choose to ignore. There is a ton of evidence that an organism carried by house cats has a direct impact on human health— but that’s not a consideration we take to heart when we’re considering adopting an adorable kitten. We choose to ignore that data point because it interferes with the outcome we seek. (Unless, of course, you happen to suffer from an autoimmune disorder or are pregnant, at which point the health impacts of the cat could be much more immediate.)
Get Grist in your inbox