GMOs: Healthy or Harmful?

Are GMOs healthy or harmful? Here is what we know. 

What Are GMOs?

Genetically modified organisms (GMOs) are plants or animals that have been genetically engineered to produce new and specific traits. For example, a plant bred to resist a certain herbicide, produce an insecticide, grow faster, or withstand harsher growing conditions.

Genetically modified seeds are patented, and cost more than conventional seeds. Because they only grow for one season, new seeds have to be bought each season. There are two main biotech firms that control the GM market, and they are Monsanto and DuPont. 

The pro-GMO sentiment centers on their supposed ability to help end hunger by producing enough food for the planet. But, when we look into the data, is it true? 

Are GMOs Safe?

The USDA and FDA considers that GMOs are safe for human health and are not a risk to the overall environment. But, when we look at the data, is any of this true?

Do GMOs Increase Crop Yield?

In a report published by the United States Department of Agriculture’s Economic Research Service on February 20, 2014, which studied genetically engineered (GE) seed use from 1998-2013, “Over the first 15 years of commercial use, GE seeds have not been shown to definitively increase yield potentials… in fact, the yields of herbicide-tolerant or insect-resistant seeds may be occasionally lower than yields of conventional varieties.” (1) 

It can only be speculated that when we introduced GM seeds back in the 90’s we expected the crop yield to increase. Indeed, the majority of farmers who use GE seeds state that one of the top reasons for using them is the potential to increase crop yield. However, since GE seeds were not tested for 15, 10, or even 5 years before we put them into commercial use, we had no way to know. Now we do.

According to the USDA report that examined 15 years’ worth of data, the answer is no, GMOs do not increase crop yield over the long term.

Do GMOs Decrease the Need for Pesticides and Herbicides?

Crops that are genetically engineered to resist pests would seem to offer cost savings to farmers, who wouldn’t have to shell out as much money on pesticides. 

However, again, when GE seeds were introduced, we didn’t have long-term studies on their efficacy in this capacity. In a meta-analysis published in 2013 in Nature Biotechnology, researchers found that more pests were becoming resistant to GM crops. Of 13 pests studied in 2005, only one was resistant to the GM crops. In 2012, that number jumped to 5. (2) While the majority of pests still remained resistant, there is clearly a possibility of the remaining species to adapt and evolve to become resistant as well. 

Not surprisingly, overall pesticide use is going up, not down. Professor Charles Benbrook published a peer-reviewed study on the impacts of GE herbicide-resistant crops on the use of herbicides. His findings: “Herbicide-resistant crop technology has led to a 239 million kilogram (527 million pounds) increase in herbicide use in the United States between 1996 and 2011, while insect-resistant crops have reduced insecticide applications by 56 million kilograms (123 million pounds). Overall, pesticide use increased by an estimated 183 million kilograms (404 million pounds), or about 7%.” (3)

In the earlier mentioned USDA report, the authors write: “over-reliance on glyphosate and a reduction in the diversity of weed management practices have contributed to the evolution of glyphosate resistance in some weed species.” They go on to explain how initially, when GMOs were first planted, the need for pesticides and herbicides did indeed decrease, however, after a few years when the weeds and pests developed a resistance, more agricultural chemicals were needed and used, resulting in an overall increase. (1) 

So, the answer is no, over the long run, GMOs do not decrease the need for pesticides and herbicides.

Do GMO Crops Increase the Nutrient Values of Foods?

A benefit of using GM crops is the ability to engineer foods that are more nutritious. In places where malnourishment is a real threat, that is good news. Rice, for example, can be engineered to contain high levels of vitamin A, a common deficiency in some developing nations. While this may be beneficial in developing nations, in the US, it’s a less persuasive argument. Most Americans have wide access to a variety of foods and supplements which are better suited to addressing nutrient deficiencies than enriched white rice. 

Additionally, the crops that are most commonly grown as GM in the US are corn, canola, and soy. All of these are also the most common ingredients in junk food. Instead of eating them as vegetables, these crops are turned into highly processed snacks and meals. This would counteract any initial higher nutrient value. 

While GMOs can be engineered to be more nutritious, there is not a strong argument for their use in the US, where our most commonly GM crops are turned into junk food, and people have wide access to not only a variety of foods but also high-quality nutritional supplements. 

Are GMOs safe for human consumption?

The safety of GMOs in the food supply is a hotly debated topic. Unfortunately, there are not currently any large, long-term, epidemiological studies on the effects of the consumption of GM crops, either in support or against. 

There is, however, a growing body of evidence from smaller studies and animal studies, which do raise a concern. One of the most popular lines of GM crops is Monsanto’s “Roundup Ready” crops. They are engineered specifically to resist Monsanto’s herbicide, called Roundup, which is made of glyphosate.  

Glyphosate exposure is associated with oxidative damage and neurotoxicity.  In a study published in the journal, Toxicology, researchers found that both chronic and acute exposure to Roundup causes excessive extracellular glutamate levels and consequently to glutamate excitotoxicity and oxidative stress in rat hippocampus. While we haven’t studied the effects of Roundup on the human brain, that does not mean it is necessarily 100% safe. We do not have research yet to prove that. Interestingly, in 2012, a French farmer successfully sued Monsanto after inhaling its weedkiller and suffering neurological damage (4).

We need more research on the long-term safety and effects of consuming GM crops.

Are GMOs Safe for the Environment?

One of the larger concerns of GMOs use is their impact on the environment.

GMOs are toxic to a number of helpful insects. This includes natural pollinators and pest predators. Monarch butterflies, a chief pollinator in North America, are especially susceptible (5). 

In a study published in the Proceedings of the National Academy of Sciences of the United States of America, researchers found that toxins from GM corn could enter nearby headwater streams and cause harm to the ecosystem, by poisoning non-target stream insects which play an important role in the stream ecosystem (6). 

Cross-pollination is another issue. Because the wind blows, there is a possibility that non-GM crops cross-pollinate with GM crops. This may pose problems in local ecosystems. Not to mention for unsuspecting farmers, who would now be unlawfully growing patented crops. When this happens, it’s possible the unsuspecting farmer could be sued by the biotech company that owns the patent. 

What’s more, GMOs can endanger biodiversity. Genetic mutations are a part of life and evolution, of which GMOs undermine. If the majority of a specific crop grown in one country, like wheat, was grown as one GM strain, if a plant disease or pest were to arise that couldn’t be repelled by the crop, there is a risk for widespread crop failure. This could be avoided by growing multiple varieties. 

The Bottom Line: Are GMOs Healthy or Harmful?

Based on the current understanding of GMOs, now that they have been in use for a few decades, it is clear they are not beneficial for consumers, farmers, or the environment, and are best avoided.