Dr. María Elena Álvarez-Buylla is an expert on the topic of genetic engineering who has co-authored dozens of papers about molecular genetics, ecology, evolution and related topics. She is a professor of molecular genetics, epigenetics, and development at Mexico’s National Autonomous University. 

Until the end of September, Dr. Álvarez-Buylla was the head of Mexico’s national science agency, CONAHCYT, the National Council of Humanities, Science and Technology. During the six-year term of President Andrés Manuel López Obrador, Álvarez-Buylla’s agency was charged with documenting the scientific evidence of the risks to human health and the environment of genetically modified (GM) corn and the herbicide glyphosate. That research led to Mexico’s precautionary policies to eliminate the use of GM corn in tortillas and to phase out the use of glyphosate. When the U.S. government last year challenged those measures as unfair trade practices under the U.S.-Mexico-Canada Agreement (USMCA), her agency provided the scientific evidence underpinning the Mexican government’s defense in the formal trade dispute, a process that is now awaiting a ruling by the three-member panel of arbitrators. 

CONAHCYT recently published a comprehensive analysis and summary of that evidence, asserting that both GM corn and glyphosate residues pose risks to human health and to the environment. Dr. Álvarez-Buylla agreed to discuss her former agency’s science-based defense of what Mexico considers its sovereign right and obligation to protect public health and the environment from GM corn and glyphosate. 

Timothy A. Wise: Since the Mexican government first announced its intentions to restrict GM corn cultivation and direct human consumption of GM corn, and also to phase out the use of glyphosate, the U.S. government has repeatedly stated that those policies have no scientific basis. The national science agency you directed was charged with documenting the science. Has Mexico answered the U.S. challenge?

María Elena Álvarez-Buylla: Yes, I think there’s ample documentation in Mexico’s USMCA filings and in the dossier that we prepared, and these show very clearly the risks of GM corn planting and consumption in tortillas and masa. We have to remember that in Mexico we consume directly much more corn than anywhere in the world, from half a kilo to a kilo a day. 

Wise: In light of the scientific evidence the Mexican government presented, has the U.S. government responded by providing any of its own scientific proof that U.S. GM corn is safe for Mexicans to eat?

Álvarez-Buylla: I don’t think so. The research on the part of the U.S. was quite poor. The U.S. rebuttal did not have up-to-date scientific evidence. Their scientific annexes ignored many of the studies, dismissing independent science and continuing to cite science that is full of conflicts of interest.

Wise: The science agency CONAHCYT’s comprehensive review of the science of risks from GM corn and glyphosate was recently published. This dossier is 200 pages long with more than 1,200 references. It presents the case that you’re talking about, which is why we had it translated into English. Why did the science agency choose to publish the document now?

Álvarez-Buylla: This dossier was indeed the result of work done by many scientists in Mexico, not only at CONAHCYT. The new government, which is also very interested in supporting decisions based on science, asked to make the dossier public. So it was released at the end of September, just before my term ended at CONAHCYT, and then published the next month.

Wise: What are the main categories of risks to human health that your research identified from GM corn and glyphosate residues that justify the precautionary policies that Mexico has followed?

Álvarez-Buylla: Many animal studies have been done on Bt corn, engineered to repel pests, showing related gastrointestinal tract issues in mammals. These have not been adequately studied in humans. Then there are the glyphosate-derived risks. But there are many lawsuits in the United States over Non-Hodgkin’s lymphoma associated with the exposure to glyphosate, and also other risks. For example, work has been done in the United States correlating the levels of glyphosate found in the samples of American people with the probability of being sick. We still need many more long-term studies in animals. The President of Mexico at the time, López Obrador, actually proposed to the U.S. government that it collaborate with Mexico on such long-term studies in animals, but the U.S. government did not agree.

Wise: Some of your own research was seminal in showing that the tortilla supply chain had been contaminated with both transgenes and glyphosate, which establishes that GM corn is getting into your local corn supplies.

Álvarez-Buylla: Yes, in fact, that study was done in 2017 in my laboratory before I started my position as general director of CONAHCYT. We found that 90% of tortilla samples from several cities, not only Mexico City, had some transgene fragment. We also found glyphosate residues in one-third of the samples that we studied. Such studies have now been repeated, and despite the fact that President López Obrador published a decree to avoid the use of transgenic maize in tortillas and in other human food, we’re still finding that some of these transgenic lines are being used for tortillas. That is worrying, because, as I said before, tortillas are consumed at very high levels in Mexico. 

It is very important to keep tortillas and all the corn-derived foods in Mexico free of GMOs and glyphosate. The [glyphosate] residues that we found in tortillas were at levels that even in the U.S. are not allowed in food.

Wise: I know that the dossier, the scientific review, also highlights the risks to the environment and to biological diversity. What are the main areas of concern there?

Álvarez-Buylla: Many studies have found the impact of GMO cultures on diversity in general, especially in lepidopterans, for example, in some types of butterflies, and in the flora and fauna, microflora, and microfauna in the soil. Glyphosate was supposed to decay very rapidly, but that is not the case in watersheds, rivers, etc. And then there is the risk of transgene flow into the native varieties. In Mexico, we have the obligation to keep this center of origin safe, not only for Mexican food production but also for the world, as it is a very valuable genetic reservoir. There are many studies that have documented that it is not possible to segregate GM from non-GM cultivars. 

Wise: I know that recently there were early indications from leaked sources that the trade tribunal on Mexico’s GM corn restrictions may well rule in favor of the US. President Sheinbaum has indicated that Mexico will seek other means to defend its GM corn restrictions. Why is Mexico so committed to these policies?

Álvarez-Buylla: Mexico is committed to these policies because corn is our basic food. The possible impact of any risk associated with GM corn would be very important for the Mexican people. The nutritional quality of Mexican native corn varieties is also better. The government is very interested in promoting their cultivation. It is very important to promote their cultivation, because the best way to preserve genetic diversity is in the hands of the peasant communities that are actively updating such diversity to adapt to local environments in Mexico.

Also, in the face of climate change, we have several studies showing that Mexico will be better equipped to cope with increases in temperature and changes in global climate if we maintain this diversity. 

Wise: By all accounts, the restrictions that President López Obrador put on GM corn and glyphosate are very popular with Mexicans, and I’ve read that they even have the commitment of the tortilla industries themselves to keep GM corn out of their products. Do you think it’s appropriate for the U.S. government to use a trade agreement to try to end such policies when the current restrictions are so popular and don’t significantly affect U.S. exports?

Álvarez-Buylla: I don’t think commercial trade agreements should interfere with the sovereignty of other countries, and I think the trade agreements themselves have statements that ensure that countries can protect their sovereignty in terms of important issues. Food sovereignty is one of the most important.

Keeping Mexican maize varieties as well as watersheds and foods in Mexico free of GMOs and glyphosate protects our food system, and therefore our health. Trade agreements should never be prioritized above the health and environment of the countries involved. This pertains not only to Mexico but also to the U.S. because I’m sure that the U.S. people are also concerned about the quality of their environment, their food, and their health. 

Wise: Mexico’s Congress is now considering a constitutional amendment to ban the cultivation of GM corn and its use in foods such as tortillas produced for direct human consumption. Why is that important?

Álvarez-Buylla: The decree by former President López Obrador is very important, and it’s a strong instrument. But I think that a constitutional change that enforces the protection of Mexico’s staple food will provide a long-term assurance that we can take care of our food system, our environment, and our health. That’s why it’s a priority for the Mexican government and the Mexican people. That is the reason why both former President López Obrador and current President Dr. Claudia Sheinbaum are putting forward these reforms.

Wise: Thank you so much for speaking with us, and congratulations on an amazing tenure at CONAHCYT and on the valuable resource you’ve provided not just to Mexico but to all of us. 

Álvarez-Buylla: Thank you. 

Interview Transcript, Timothy A. Wise with María Elena Álvarez-Buylla, Nov. 14, 2024