GMO Study Discredited?


The genetically modified organism (GMO) debate flared up again this week.  Last year, a French study led by Gilles-Eric Séralini claimed that Roundup and corn modified to be resistant to Roundup was toxic.  Roundup is a very common weed killer and some crops are genetically modified to withstand it.  Rats in the study developed grotesque tumors.  There was a big outcry of criticism in response to this study, and the journal that published it is now threatening to retract the study.  I don’t know if the study is junk or not.  Séralini’s response to critics seems fairly reasonable.  But if it is a poorly designed study, then I wonder why there aren’t properly designed long-term studies of Roundup safety that would settle this matter more definitively.

Just to clarify my position, I remain skeptical of GMOs and of the safety of consuming Roundup in particular, but I in no way intend to advocate for GMOs to be banned.  GMOs clearly hold huge promise for solving world hunger problems.  I just don’t like the way this debate is being framed.  GMO skeptics are painted as being anti-science.  This might largely be true, but some of the blanket statements issued by scientific organizations to assert the scientific consensus of GMO safety seem… well, unscientific.  Consider this statement on GMO safety by the National Academy of Science:

All evidence evaluated to date indicates that unexpected and unintended compositional changes arise with all forms of genetic modification, including genetic engineering. Whether such compositional changes result in unintended health effects is dependent upon the nature of the substances altered and the biological consequences of the compounds. To date, no adverse health effects attributed to genetic engineering have been documented in the human population.

Ok, so that means that someone ran GMOs through the gold standard of scientific evaluation and performed a large-scale, double-blind study to prove the safety of GMOs on humans then, right?  Umm, no.  In fact, it appears that not many long-term studies of GMO safety have even been performed on mammals, let alone humans.  So I wonder how the NAS confidently arrived at the conclusion that GMOs are safe.  Well, to be fair, they do hedge their bets with that statement, but consider the final sentence:

To date, no adverse health effects attributed to genetic engineering have been documented in the human population.

See, the problem with this statement is that there have been no studies of GMO health effects on humans to produce this documentation of harm.  There is no control group to compare GMO eaters to.  Some estimate that 60 to 70 percent of the processed food in the US contains GMOs.  You need a population that isn’t eating GMOs to compare the rest of us to.  One can’t just say that cancer rates have been flat, so there has been no cancer impact from GMOs.  What if cancer rates would have gone down if GMOs weren’t being eaten?  The Amish might be people to study, except for the GMO cross contamination problem and the fact that their lifestyle is so radically different that it would introduce many confounding factors (i.e. Maybe the Amish are healthier because of being closer to the land.).

Another problem is that it will be very hard to document the harm from GMOs if it doesn’t happen immediately.  Who can say what caused health problems that occur after years of GMO consumption?  How could it be shown that GMOs caused harm as opposed to the water that was consumed or other potentially toxic exposures?  The NAS’s final sentence is a bit like saying, “To date, the general public has not documented the existence of the Higgs Boson.”  The public doesn’t have the tools to show which substances might cause long-term harm.  We need scientists to do that for us.

Agribusiness clearly has the cash and political clout to influence legislation.  It’s not realistic to expect any regulation that requires GMOs to be tested for safety the same way that say, drugs are tested.  But it’s not unscientific to question GMO safety given the scarcity of mammalian studies.  Yes, GMOs look good on paper, but show me the empirical data.  Salmon and chickens don’t seem to be hurt by GMOs, but human biology is more complicated.  I would feel much more confident if someone would just run a proper long-term human clinical study and be done with it.  The money spent to prevent GMO labeling in California could have funded plenty of research.  

I would feel much more confident if someone would just run a proper long-term human clinical study and be done with it.  The money spent to prevent GMO labeling in California could have funded plenty of research.

Of course, it’s hard to control what people eat long-term.  But it seems that low security prison populations might provide good candidates.  (They could be given some incentive to participate, not be forced.  The test group would not be any worse off than the general population, after all.)  Their diet is largely controlled already, and I assume that low security convicts stab each other less frequently than high security prisoners, so that would be one less thing to control for when computing mortality rates I guess.

My friend Razib criticized my squeamishness and said that there are plenty of other substances and activities that are probably worse for human health than GMOs.  It’s certainly rational for starving folks in the developing world to risk potential health problems at some time in the future in order to eat Vitamin A enhanced GMO rice today, for example.  But I don’t live in the Global South, and I personally already avoid a lot of the things that more obviously cause harm, so I am a crybaby and I don’t want to touch this GMO stuff until they can show me some REAL scientific evidence of safety.

I know, I know.  I just wrote a post last week examining why many of the scientists I know dismiss dietary interventions to improve health.  Perhaps I am not updating my beliefs properly here?  Give me time, self-optimization is a difficult habit to break, especially since I am more of a fox than a hedgehog.  As Anatoly pointed out recently, generalist “foxes” might be more inclined to self-optimization.  In the final analysis, the world will probably be better off with GMOs than without them.  They provide the potential to feed far more people with less land and fewer resources than organic farming.  Far be it from me to stand in the way of progress.  Pour me a shot of Roundup.

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