It’s almost impossible to turn on the TV without seeing news reports or commercials about GMOs. You’ve probably encountered GMO-free labels on products at the grocery store as well. They are one of the most hotly debated health topics today, but what are GMOs and why do people care so much about them?
Information about GMOs is complicated and can be difficult to understand. We spoke with Keith Roach, MD, Sharecare’s chief medical officer, and Michael Kantar, PhD, and assistant professor at the University of Hawai‘i, Manoa to find out if this controversial topic can affect your health.
What are GMOs?
GMO stands for genetically modified organism. You may also see references to GM or GE (genetically engineered) technology. According to the World Health Organization, GMOs are defined as “organisms (i.e., plants, animals or microorganisms) in which the genetic material (DNA) has been altered in a way that does not occur naturally by mating and/or natural recombination.” Generally, this means the insertion or deletion of genes in an existing plant’s genome to highlight desirable attributes. For example, some crops have been engineered to be insect or herbicide resistant to potentially reduce the need for insecticides or herbicides in commercial farming.
Some scientists, however, think this definition of GMOs is too narrow, and that virtually all plants humans eat today are the result of genetic modification. Dr. Roach’s definition of GMOs is broader: “I would define a GMO as any foods that come from plants or animals that don't exist in nature without human manipulation.” This is an important distinction because almost all foods are the product of some level of human manipulation, either through domestication or purposeful selection and cross-breeding.
Dr. Kantar echoes this idea: “The people who are in the plant community who are around plants really consider almost all plants genetically modified. Nature isn’t static, we select things all the time. The domestication process itself means that those plants no longer survive in the wild.”
While some scientists may place nearly all plant species in the GMO category, the standard definition only includes plants that have had specific manipulations made to their genome in a man-made setting that could not happen in nature.
How modern science blurs the lines
Advances in science make it harder to distinguish between GMOs and conventional breeding methods like domestication and cross-breeding. One method that is considered conventional breeding is to irradiate plants in a lab setting to force mutations faster than they might occur in nature. Once scientists identify a desirable mutation, they study the plant for safety and may continue to breed it. Although this process involves radiation or other chemicals, the resulting plant strains are not considered GMOs.
By comparison, advances in DNA technology, such as CRISPR, now allow scientists to pinpoint specific genes and edit them out. “With CRISPR technology there's actually no insertion of any foreign DNA,” explains Kantar. “So, the modification is indistinguishable from a mutation that you would just find from walking through a field.” This technology, however, is considered a GMO.
As science continues to advance, some doctors and scientists, like Roach, feel the distinction between GMO and non-GMO will become meaningless, given the practices of conventional breeding that have impacted plants and animals intended for consumption over the millennia.
Are they safe?
According to a 2015 Pew Research Center poll of American Association for the Advancement of Sciences (AAAS) members, 88 percent of scientists polled believe that GM foods are generally safe.
This viewpoint is also in line with evidence. Rigorous testing and studies have shown no major health risks associated with eating GMOs. As Roach explains, “trillions of meals have been eaten by people consuming genetically modified foods, and there is no disease that has been definitively pointed out as occurring to it. This appears to be a very low risk or even theoretical risk [of that] happening.”
In 2016, the National Academy of Sciences (NAS) weighed in on GMOs with a lengthy report about their safety and environmental impacts. The report concluded, “While recognizing the inherent difficulty of detecting subtle or long-term effects in health or the environment, the study committee found no substantiated evidence of a difference in risks to human health between currently commercialized genetically engineered (GE) crops and conventionally bred crops, nor did it find conclusive cause-and-effect evidence of environmental problems from the GE crops.”
GMOs are also vigorously tested before going to market. As Kantar explains, “depending on the plant species it can take anywhere between 6 and 30 years” before approval.
The AAAS board of directors goes into further detail on the testing process for GMOs: “In order to receive regulatory approval in the United States, each new GM crop must be subjected to rigorous analysis and testing. It must be shown to be the same as the parent crop from which it was derived and if a new protein trait has been added, the protein must be shown to be neither toxic nor allergenic. As a result, and contrary to popular misconceptions, GM crops are the most extensively tested crops ever added to our food supply.”
With such rigorous testing and a lack of evidence stating they are harmful, it’s easy to see why scientists, including Roach and Kantar, overwhelmingly agree that GMOs are safe.
If GMOs are safe, why do we keep hearing about them?
There’s a huge disparity between how scientists and the public view GMOs. In the same Pew poll that showed 88 percent of scientists believe GMOs are safe to consume, only 37 percent of the general public agreed. That 51 percent difference was the largest opinion gap between scientists and the public in the poll.
Why does the public have such a negative view on something that scientists agree isn’t harmful? “I think a lot of it is because there's been an effective public relations campaign against genetically modified foods,” says Roach.
There are also concerns that GM technology could lead to increased food allergies or toxins that have yet to be identified. Because of this, Roach and others caution that there needs to be continued, vigorous testing of new GMOs. “There is potential, however remote, that you are going to be doing something wrong. It does make the case, I think, that continued testing and vigilance is still warranted,” says Roach. Even so, when asked if he thought GMOs were safe, Roach responded with a resounding “absolutely.”
Regardless of public opinions, it’s clear that GM research and technology is here to stay. With the world’s changing climate leading to draught, natural disasters and varied growing conditions, some scientists believe that advances in GM technology are the only way to feed the world’s growing population.
