What is Genetically Modified Food?
Plants and animals that have been genetically engineered for consumption are considered genetically modified (GM) food. Genetic engineering is the way that the DNA of the organism is manipulated, often directly by means of transplanting parts of DNA from other organisms. Food has been genetically modified for a variety of reasons, such as being more resistant to herbicides, not being as vulnerable to pests, less affected by drought, and more nutritious.
A Concerned Population
Genetically modified food has become an increasingly prevalent matter of discussion in recent years, ranging from debates about whether or not they are healthy to if the government should require them to be labeled.
Danimals, a popular children’s yogurt drink, posted a video advertisement on Facebook marketing the fact that their product is labeled as “Verified” by the Non-GMO Project. Information about the Non-GMO Project can be found here, but also consider this analysis of labeling. Notice that there is not a strict line between advocacy and dispassionate science. These screenshots of responses were taken from real people, with names and faces blurred to protect the individuals’ identities.
GM food is a charged and actively debated issue. Discourse like the example above happens frequently both on and off the internet. However, what is particularly interesting with the GM food case is that it is not a politicized issue. As seen in the segmented bar graphs below, in addition to opinions surrounding this topic not being split across political party lines, they are similar with regards to gender, ethnicity, and age.
Data from PEW
Part of the reason why the public is divided is because there is apparent scientific controversy.
Twenty years after commercial cultivation of GM crops began, a bona fide report of an adverse health effect due to a commercialized modification in a crop has yet to be reported.
— Hilbeck et al. Environmental Sciences Europe (2015)
In other words, this study concludes that there has not been any authentic reports of GM food negatively impacting health.
[T]he scarcity and contradictory nature of the scientific evidence published to date prevents conclusive claims of safety, or of lack of safety, of [genetically modified organisms] GMOs.
— Plant Biotechnology Journal (2017)
The authors of this study determined that because there have been several reports on both sides of the debate on GM food, no conclusion on the safety of genetically modified food can be reached.
Both of these studies looked at the previous research that had been done on genetically modified foods and had significantly different findings. There is a significant amount of scientific research on genetically modified food that has been conducted and published, but a consensus amongst scientists has not been crystal clear.
Why is it so Hard to Come to a Consensus?
The main reason it is difficult to reach unanimity is because the studies that can be conducted on the effects of genetically modified food are not ideal. For one, tests cannot be run on individual humans. As a result of this, scientists must turn to animals, like rats, that are known to be similar to humans with regards to responses to an experimental treatment.
Furthermore, GM food is still fairly new. The Flavr Savr Tomato was the first, approved by the FDA in 1994. Since this is such a recent development, sufficient longevity studies do not exist to confidently determine if GM food has significant long term health effects on humans.
Scientists look at population trends to try to determine if any of them can be associated with a rise in the production and consumption of GM food. However, studies like these make it very difficult to prove causation, as several confounding variables are present. For instance, many individuals have analyzed obesity trends and struggles, as factors such as socioeconomic status, exercise lifestyles, and availability of fresh food also impact these rates.
So what is the best we can do when it comes to finding out if GM foods are safe to consume?
The Most Dispassionate Analysis
In May of 2016, the National Academies of Sciences, Engineering, and Medicine (NAS) released a 420 page report analyzing all of the research that had been collected on GMOs.
The NAS is a nonprofit organization that consists of members elected by peers for outstanding work in their fields. In other words, these members are the best of the best, and the leading experts in their areas of study. The mission statement of this organization is to provide nonpartisan and objective advice to government officials on the most pressing issues facing the nation. They respond to challenges in policy with science, publishing about 200 reports a year.
As evidenced by the timeline above, the NAS has a very good track record when it comes to scientific reports. Even though they are often viewed as a head of public perception, they do not just follow political whims. They are deliberate in their research, exemplified by the way they simply validated the existence of climate change in 2001, and did not release a statement saying climate change is human caused until there was sufficient evidence thirteen years later. Thus, their report that GM food is safe for humans, published in 2016, is in a progression of reliable statements from a trustworthy organization.
NAS Report on GM Food
The consensus report from the NAS on GM food is 420 pages long and analyzes its effects on economics, agriculture, safety, and human health. In this article we will focus on that last aspect.
[T]he committee found no differences that implicate a higher risk to human health from GE foods than from their non-GE counterparts.
This conclusion was reached by considering evidence from three major categories.
The NAS committee recognized that the design of many of these studies was not optimal, using small sample sizes and therefore not having enough statistical power. However, the results from the available studies combined allowed us to conclude that animals were not harmed by GM food. The studies that the NAS analyzed were conducted on both rodents and livestock.
With regards to rodents, the NAS made a point to analyze the controversial Séralini study, which some say “proves” that GMO’s are harmful to health. The committee found that while the number and strain of rats used in this study were not atypical, the conclusions of the study indicate that a longer trial with a larger sample size should be conducted, but do not themselves make a statement about the safety of GM food. Due to this, the findings of several multi-generational rodent studies, which showed no significant adverse health effects as a result of the modified feed, carried a larger weight in the eyes of the committee.
Livestock studies are known to provide more long term data, as they span the time period before and after the introduction of GM feed. They primarily consider consumption, growth, organ size, immunological markers, and microbe populations, much as the rat studies do. One must be cautious when using these studies as a reference, because while they do test for relevant correlations, they do not determine cause and effect. Regardless, the NAS committee found no sufficient evidence that would allow them to conclude that GM food has adverse health effects.
The NAS committee concluded that differences between GM food and non-GM counterparts when it comes to levels of nutrients and chemicals can be explained by naturally occurring variation. In making these comparisons, it is important to consider processing methods, variety, growing conditions, and laboratory equipment, as it makes it hard to attribute differences between crops solely to genetic variation. In the United States, it is voluntary to submit nutrient and chemical composition data on GM crops to the FDA, but it is almost always done by developers, who compare their products to others already in the food supply.
Incidence of Health Problems
Analysis of epidemiological data sets comparing countries with high and low GM food consumption revealed no significant differences for rates of cancer, obesity, kidney diseases, and other disorders.
One of the most common claims about GM food is that they “cause cancer.” The NAS committee investigated this claim by comparing the prevalence of cancer in regions of the world where GM food is prevalent (like the US) and where GM food is virtually nonexistent (like the UK). One of the most powerful graphics from the report (below) reveals that the cancer trends in countries that consume large amounts of GM food do not significantly differ from those that consume less.
Plot A compares breast cancer cases, while plot B compares cervical cancer cases.
While it is impossible to conclude from this analysis that there is no relationship between GM food and cancer, as there are variables that may hide a trend, such as a delay in the onset of cancer, the evidence at hand does not support claims that the growth of GM food consumption has increased the prevalence of cancer.
Society is concerned about GM foods today due to the significant amount of frightening media that they observe here and there in their daily lives. Educating the world about the truth associated with GM foods would help the global population relax greatly relative to this perceived need to be concerned about GM foods, when there is actually no sufficient evidence that they pose a threat to human health.
This article focused on human health related to GM food, but this is a multifaceted topic. I encourage anyone who is interested to look into why GM food is important and the other sections of the NAS report or the report in brief.