Know Your GMO: Deciphering The Science Behind The Debate

image courtesy of Chiot’s Run via Flickr modified by Curiousmatic 

When it comes to contemporary food fervor, Genetically Modified Organisms (GMOs) are one of the most divisive, ubiquitous, and sometimes downright conspiratorial topics on the table.

In camp one, the most enthusiastic GMO proponents hail their synthesized food crop as a financially feasible solution to global hunger—claiming that they offer vitamin enrichment, herbicide resistance, and diminished environmental impact over conventional farming.

So, who could argue with that, you ask? As it turns out, a whopping 52 percent of Americans can.

In camp two, anti-GMO claims run from skeptical to the vehemently opposed. Adamant GMO naysayers claim that consumption can lead to a myriad of negative health outcomes, from gastrointestinal disorders, to damaged immune systems, and even accelerated aging. National supermarket giant, Whole Foods, even announced that it would begin labeling all GMO products in 2013–labeling being one of many hot button issues regarding GMO legislation.

But what does the science say? Contrary to common perception, there are in fact over 2000 peer reviewed studies surrounding various GMO issues. Below, we’ve analyzed a few of the most hotly debated GMO topics, and the credible (and not so credible) studies surrounding them. Let’s take a look.

Horizontal Gene Transfer

Concern: Horizontal gene transfer simply means “the transmission of DNA between genomes,” made possible through plasmids and bacteria. This is a process which happens throughout nature.

In regard to GM foods–specifically those which carry a particular antibiotic resistant gene marker–HGT is scrutinized in relation to the transfer of potentially harmful DNA via the human intestinal tract and gut. GMO opposers claim that such genetic material could cause unintended consequences in the human gene pool, making antibiotics less effective in treating illnesses.

Most comprehensive study: In a decade-long sequel to a 15-year-long GMO study by the European Union, HGT as a result of GM food consumption was concluded as “highly unlikely.” An additional study in the journal of Environmental Biosafety Research does, however, acknowledge more specific concerns of HGT in GM crops.

The study states that it may take “thousands of generations” for transgenic effects to become clear. Despite some reservations, both studies still arrive at similar conclusions–those being that HGT happens at too minute a rate to adversely affect human health.

Seralini Study

Eric Seralini is responsible for what is possibly the most cautionary study of GMOs to date. The validity of his findings, however, have been widely criticized by the scientific community and even the European Union.

The study: In Seralini’s 2012 study, 200 rats were observed for period of two years–almost their entire lifespan–which is significantly longer than similar 90 day studies. The rats were split into 10 groups of 10 female and 10 male rats, and fed different amounts of Monsanto’s GM herbicide resistant corn, some of which had been sprayed with Roundup (a popular weed killer) Three groups were fed differing doses of roundup in their drinking water, and the last group was fed regular water and food.

The results:

  • Engineered corn group showed a 70 percent mortality rate before normal aging for females and a 50 percent mortality rate for males

  • Many GM reared rats developed large tumors

  • Control group showed 30 percent mortality rate for males and 20 percent for females

  • GM rats showed significantly more kidney and liver damage than control

The criticism:

  • The sample sizes of rats were too small to draw any real conclusions

  • The amount of roundup given to different groups did not correlate with increased tumors or negative health outcomes

  • Journalists reporting on the study were forced to sign confidentiality agreements stating they would not consult other scientists in their coverage

  • Only pictures of GM and herbicide exposed rats were shown following the studies. Control rats have yet to be seen

  • The study was republished using the same data and ignored all major criticisms

Seralini’s study drew significant flack from an array of independent researchers, and was eventually retracted by its original publisher, Food and Chemical Toxicology, in 2013. Similar studies have yet to replicate Seralini’s findings.

It may also be worth noting that skepticisms relating to pro-GMO research have also been posited–particularly the fact that much of it may be clouded by multinational seed corporations like Monsanto.

Increased Herbicide Usage

Herbicide resistant “Superweeds” have become a hot item in the crusade against GM crops, and if a 15 year study published in Environmental Sciences Europe is any indicator, such claims may have a rightful place amongst future GMO debates. Here’s what the study tells us:

  • Between the introduction of mass produced GM crops in 1996 to 2011 GM crops have led to a 404 million pound increase in pesticide usage

  • Since “roundup ready” crops were introduced, some weeds have become resistant to glyphosate–an integral weed-killing ingredient of roundup.

  • Author of the study, Charles Benbrook, says resistant weeds are amping up the volume of herbicide usage by 25 percent each year

  • Benbrook warns that since herbicide usage is expanding, that farmers are starting to resort to older and more high risk chemicals

A statement by over 20 different scientists from the American Association for the Advancement of Sciences (AAAS) has challenged the board of directors stand in opposition of GMO labeling. In their statement, the scientists and physicians cite a number of reasons for their call to continue GMO labeling, citing most prominently the quandary of herbicide resistant “superweeds” and the “chemical treadmill” which they proliferate.


While GMO research continues, the dialogue over the safety of such crops carries on. For now, however, the debate remains as such–a debate. Despite the majority of research pointing to general safety, by definition, it would be hyperbolic to call GMO safeness a scientific consensus. As consumers, understanding the science (and what science to trust) behind GMOs may be the only step forward.

We measure success by the understanding we deliver. If you could express it as a percentage, how much fresh understanding did we provide?
James Pero