Is GMO Corn Safe to Eat? Understanding the US–Mexico Corn Trade Dispute

Mexico banned the import of GMO corn—most of which comes from the United States. Why has the country banned it?

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Genetically modified organisms (GMOs) have been on the commercial market for many years, yet their safety remains contentious. Is it safe to eat GMO food? Why has GMO corn triggered a trade dispute between the United States and Mexico?

About 90 percent of the corn planted in the United States is genetically modified, and Mexico is a major buyer, purchasing nearly 30 percent of the total U.S. corn exports. However, in 2020, Mexican President Andrés Manuel López Obrador issued a decree banning the import of GMO corn starting in January 2024.

As a result, the United States has initiated formal negotiations under the United States–Mexico–Canada Agreement (USMCA), claiming that the ban on GMO corn violates the trade agreement and that Mexico has not provided scientific evidence to support its stance. Mexico, however, insists that GMO corn threatens human health and that GMO seeds endanger its agricultural traditions and cultural identity.

Why Does Mexico Oppose US GMO Corn?

Xiaoxu Sean Lin, an American virologist and former U.S. Army Research Institute researcher, noted on the Epoch Times’ “Health 1+1” program that this dispute is closely related to Mexico’s culture and lifestyle. Corn is a staple food in Latin America, with Mexicans consuming at least 10 times more corn than Americans. Therefore, safe corn is crucial to the health of the Mexican population.

Mr. Lin believes that the current dispute over GMO corn involves not only economic interests but also considerations regarding human health and the environment, particularly its impact on the ecological balance.

He pointed out that Mexico views GMO corn from a preventive perspective, fearing the risk of genetic contamination. Specifically, GMO-crop pollen can travel long distances and cross-pollinate with local varieties, potentially altering their genetic composition.

In the United States, most corn is planted using seeds from large companies, which produce only a few genetically identical corn varieties for large-scale cultivation. In contrast, Mexican farmers plant heirloom corn that comes in various colors and sizes. The genetic combinations in different local corn varieties can help corn adapt better to the environment. Introducing GMO corn could potentially affect the genetic diversity of Mexico’s domestic corn.

Moreover, toxins produced by GMO products will inevitably enter the soil and ecosystem, potentially affecting the food chain and causing long-term environmental impacts.

The Glyphosate Ban in Mexico

In addition to banning GMO corn, the Mexican government plans to ban the use of the herbicide glyphosate. Glyphosate is a widely used herbicide that can kill almost any natural plant on Earth.

Scientists have introduced genes that resist herbicides into crops to increase yields. When farmers plant these GMO crops, they can use herbicides to eliminate weeds without harming the crops themselves.

Mr. Lin stated that the Mexican government considers glyphosate harmful to humans, and planting GMO corn will inevitably involve the use of glyphosate, compounding the issues.

Some academic literature suggests that glyphosate may increase the risk of cancer, endocrine disruption, celiac disease, autism, anemia, leaky gut syndrome, and other conditions. In 2015, the International Agency for Research on Cancer (IARC) reclassified glyphosate as “probably carcinogenic.” With the evolution of GMO crops and the widespread use of glyphosate, approximately 48 weed species have developed resistance to it. As a result, around 20 countries have restricted or banned the use of the herbicide.

An animal study found that pregnant mice and their offspring exposed to glyphosate exhibited abnormal gut microbiota. Additionally, the offspring showed autism-like behaviors. Researchers believe that an increase in harmful bacteria in the body may affect brain function, potentially leading to autism.

For humans, ingesting large amounts of glyphosate in daily life is uncommon, so more research is needed to understand its potential impact on autism in humans.

However, since the widespread cultivation of GMO crops in the 1990s, human intake of glyphosate has steadily increased, which is concerning. A study published in the Journal of the American Medical Association (JAMA) in 2017 revealed that from 1993 to 2016, the average glyphosate level in the urine of older adults in Southern California increased significantly from 0.024 microgram per liter (μg/L) to 0.314 μg/L, representing more than a 10-fold increase.

Why Is GMO Corn Resistant to Pests?

Scientists have introduced genes that produce the insecticidal “Bt protein” into crops, enabling the cultivation of crops with insect-resistant properties. These GMO crops exhibit immediate toxicity to insects, as the insects’ gut enzymes convert the toxin into an active form. This active toxin then binds to specific receptors in the insects’ gut, forming small holes that kill the insects.

In contrast, this toxin is harmless to mammals, including humans, as their intestines lack the corresponding receptors. Additionally, the higher acidity in mammalian intestines degrades the Bt protein, ensuring it poses no short-term harm to humans.

However, Mr. Lin noted that while consuming GMO foods may not cause immediate discomfort, their long-term effects on human health remain unknown. This is particularly concerning, as the Bt protein content in the latest GMO corn has been increased to combat rising pest resistance. An increase in dosage could indicate an increase in risk.

The Argument Supporting GMO Foods

In 2016, 168 Nobel laureates jointly urged Greenpeace to reconsider its opposition to GMO foods. Sir Richard Roberts and his team, who won the Nobel Prize in Medicine in 1993, initiated the petition. Sir Roberts believes farmers have used various techniques to select desirable crop traits for thousands of years and views GMO foods as a solution to malnutrition in developing countries. Additionally, he pointed out that there have been no confirmed cases of health damage from consuming GMO foods to date.

However, Mr. Lin criticized such petitions as being somewhat misleading. “Science is constantly evolving. How many drugs have humans developed that initially seemed to have no side effects, only to discover significant side effects 10 or 20 years later? This is not uncommon in history, is it?”

He respects the Mexican government’s cautious stance on GMO technology, as the large-scale production of these foods can have significant impacts on both human health and the environment.

Views expressed in this article are the opinions of the author and do not necessarily reflect the views of The Epoch Times. Epoch Health welcomes professional discussion and friendly debate. To submit an opinion piece, please follow these guidelines and submit through our form here.