The Promise of GMOs: Mycotoxins

This is a part of the series The Promise of GMOs. Do GMOs live up to the promises of the biotech industry? In the case of reducing dangerous mycotoxins, there is data to back up industry claims.

Maize ear showing cottony growth caused by Fusarium ear rot (Gibberella fujikuroi, anam. Fusarium moniliforme). The fungus produces the mycotoxin fumonisin. Photo by Thomas Lumpkin of CIMMYT via Flickr.
Maize with Fusarium ear rot. Photo by Thomas Lumpkin of CIMMYT via Flickr.

Producing foods free of toxins such as mycotoxins

BIO’s claim here is that “Biotech is helping to feed the world by: Producing foods free of … toxins such as mycotoxin.”

Verdict: Promise met.

Mycotoxins are produced by some fungi that infect plants, and when consumed they can cause a variety of health problems in humans and other animals. The plants can get infected in the field, and the fungi can multiply if storage conditions are not quite right.

In the US and most other developed countries, we’ve used careful farming and storage methods to greatly reduce mycotoxins in food to the point that most people have never heard of them (although there are still outbreaks, especially in peanut). In the US, mycotoxins are primarily a health concern for livestock.

In Africa, unfortunately, mycotoxins are still a major health problem for humans. The following is paraphrased from a seminar abstract by the London International Development Center:

Africa experiences largely uncontrolled contamination of staple foods by two mycotoxins: aflatoxin and fumonisin. Maize is the main source of both. Peanuts, groundnuts, rice, and dried cassava are also sources of aflatoxin. Mycotoxins have huge hidden health costs. Fumonisin is associated with esophageal cancer, spina-bifida, and infant stunting. Aflatoxin alone contributes to >40% of the burden of disease in developing countries. Aflatoxin promotes liver cancers, suppresses immune systems, interferes with protein and nutrient absorption, and accelerates the progression of HIV and associated opportunistic infections like TB. There is a very strong correlation between HIV transmission and maize consumption that may be due to fumonisin, although more research is needed to prove a cause.

Managing  mycotoxins is difficult. Even when food is known to be contaminated, it will get eaten due to food insecurity. Most foods in Africa are traded in informal markets, so regulation is ineffective, and regulation will raise the price of food. Farming methods to reduce myctoxins do exist, but small farmers are unlikely to adopt them without some sort of subsidy. There are at-home food additives that bind the toxins that may be more affordable, but they need to be continuously distributed.

In short, mycotoxins are very bad news in Africa, and it’s a difficult problem to solve. Mycotoxin-producing fungus is worse in foods that have a lot of insect damage: the fungus enters the grain through the bites insects take. A Bt corn reduces insect damage which in turn reduces mycotoxins. A 2010 review of 23 studies of mycotoxins in corn (full text) found that 19 of these studies “came to the conclusion that Bt maize is less contaminated with mycotoxins than the conventional control variety in each case.”

With regard to mycotoxins, the verdict is promise met. However, I think one could argue that this was a pleasant surprise rather than an intended effect of Bt crops, although I’d be interested to see if anyone has evidence that the biotech industry knew in advance that Bt would reduce mycotoxins.

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Anastasia is Policy Director of Biology Fortified, Inc. and the Co-Executive Editor of the Biofortified Blog. She has a PhD in genetics with a minor in sustainable agriculture from Iowa State University. Her favorite produce is artichokes!