Over the last few days there has been a flurry of blogging activity about a study claiming “organ-toxic effects” in mice fed with GMO corn. The summaries of the study one sees are certainly scary, but if you read the original paper it is not nearly as clear as these commentators imply – in fact it is a really strange paper to read (seriously, have a look). Rather than go into the many legitimate questions about this research, I will simply refer you to a very lively, but technically sharp comment stream about it. Instead of getting into this fray I’d like to try to put this new “threat” into perspective.
It is ironic that at the same time this uproar is swirling around one bit of uncorroborated evidence for toxicity in corn, an extremely well documented toxin is occuring at unusually high levels in the 2009 US corn crop that is now entering the food supply. Yet there is no outrage, no activism, no calls for a ban, not even a mention on a “green blog” (until now). What am I talking about? If you had been following the specialized (but very public) press for farmers, grain traders and ethanol producers this fall and winter, you would know that there has been an exceptionally high level of contamination of the US corn crop this year with a toxic chemical called deoxynivalenol or “DON.” This contaminant is an epoxy-sesquiterpeneoid that is a “type B trichothecene.” It is a protein synthesis inhibitor which has the effect of increasing the brain’s uptake of tryptophan and thus to make more serotonin. It also irritates the gut. Animals exposed to it reduce their feed intake, sometimes severely, and they develop esaughageal stomach ulcers. It has potential chronic effects as well having been shown to be genotoxic in a chromosomal aberration assay with rat hepatocytes. The levels of this toxin are high enough this year that it has changed the balance of truck and rail traffic in parts of the Midwest as pork producers in particular scramble to avoid the toxin by shifting feed sources (swine are particularly sensitive to the toxin).
Why The Missing Concern?
So, a question. Why is a single bit of un-collaborated evidence published in a relatively obscure journal getting all sorts of fevered attention among activists and bloggers when unprecedented levels of an extremely well documented toxin are getting zero attention? I propose that it is simply a function of the source. In one case it is a corporation that people love to hate. In the later case it is… Mother Nature.
Mother Nature: Friend and Foe?
Yes, Mother Nature. Do a Google News Search for “vomitoxin” (the colorful and descriptive, common name for DON toxin) and you will find scores of articles describing how the unusual weather patterns this past growing season and a severely delayed corn harvest have resulted in significant incidence of this toxin that is generated by the grain mold, Giberella zea (unmodified, GMO and Organic corn are all effected). This particular toxin issue is unusual in corn. It is usually just a periodic issue in wheat and barley. As scary as this toxin sounds in my description above, unless you are a pig, this is actually not a big problem. There is a 1 ppm FDA threshold for DON in human foods, and so the companies who make corn-based ingredients for the human food supply will be spending a lot of money on testing this year to say under that level. This risk will be managed even though the toxicity of DON is much more dramatic than anything that might have been detected in the GMO corn study that has attracted so much attention.
Further Perspective on Risk
By the standards of mycotoxins , DON (vomitoxin) is pretty wimpy. It is not even classified as a carcinogen. It’s toxic profile is nothing compared to the mycotoxin, fumonisin, which leads to neural tube defects in developing fetuses and is also tied to esophageal cancer in humans. Fumonisin also causes leukoencephalomalacia in horses. And fumonisin does not even begin to compare to the nastiest of all Mother Natures mycotoxins – Aflatoxin. That natural chemical is the most toxic carcinogen know, and it a well documented, major cause of death among poor people in Asia and Africa where the food system involves poor growing and storage practices, and yet is rarely monitored for such threats. Just to callibrate risk, the FDA thresholds set for human foods with respect to aflatoxin are 1000 times lower than for DON, around 1 part per billion. Yes fumonisin and aflatoxin actually occur in corn. Aflatoxin can also be found in tree nuts and particularly in peanuts. There are many other mycotoxins that can occur in other foods. So when it comes to toxins and human health there are some very real risks that just happen to lack a convenient source to blame. What do activists say about these chemicals?
Is This on the NGO Radar?
I checked the website of the Union of Concerned Scientists. Apparently mycotoxins are not among their concerns. I checked the Center for Environmental Health which says they are “protecting your family and your community from toxic chemicals.” Apparently mycotoxins that actually sicken and kill people are not in the scope of that protection. So I checked Greenpeace (involved in funding the GMO corn study in question) and the only document on their site that mentioned anything to do with mycotoxins was a 1991 critique of the environmental movement that is really interesting. On to Friends of the Earth who’s slogan is “we champion a healthy and just world.” A leading cause of death among the poor is not an issue they champion. Finally I checked the National Resource Defense Council (NRDC), the group that raised the risk of Alar based on flawed evidence back in 1989. Their site had two articles saying that low levels of aflatoxin had been detected in infant formula, but no mention of the much more problematic levels of contamination that continue to occur. None of these groups described activities to help mitigate the threat of mycotoxins. For the developed world I suppose that could be because of their great confidence in the food industry (well, maybe not). For the developing world I really can’t explain the absence of attention.
What Would Be An Appropriate Response?
Do I want these organizations to use their considerable emotive language skills to alarm the public about the threat of mycotoxins? Certainly not! But perhaps they could help to educate people about the fact that there is no such thing as a zero-risk food supply. They could help educate the public that what is needed is a way to compare relative risks and then to manage them appropriately. They could offer the perspective that we live in a fairly toxic world (thanks Mom!!!) and yet at least for those in the parts of the world that rationally manage risk, we are doing quite well. They could explain that, at most, this recent study suggests the need for a better designed and less agenda-driven (by either side) follow-up study.
Fighting the Solutions
That would probably be asking too much, but the real problem is not that these organizations have a double standard about the actual health threat of mycotoxins. The problem is that these same organizations and activists aggressively campaign against some of the best ways to reduce mycotoxins in the food supply. Plants that are protected against insect feeding by insecticide sprays or by GMO insect resistance don’t get the feeding damage that allows the mycotoxin-generating fungi to infect. Drought-stress tolerant GMO crops (coming soon for corn) are less likely to be contaminated with aflatoxin, and this is why the Gates Foundation is funding research to bring this technology to Africa (to be offered to farmers for free). There was a GMO trait in wheat to reduce vomitoxin that Greenpeace successfully blocked. All of these incremental solutions to a real toxic threat are opposed by most of the groups listed above. During its anti-GMO efforts about wheat, Greenpeace Canada listed the potential reduction of a mycotoxin in the food supply not as an “advantage of the technology,” but as a “campaigning issue.”
If we banned any food for which there is an isolated, high-rate, rodent feeding study showing marginally statistical differences in non-lethal effects, there would be virtually no allowed foods. Whether this particular study has any importance remains to be seen. In the mean time, a little perspective would be helpful.
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Moldy corn image from Gary Munkvold, Iowa State University