Are GMOs safe?

This is the first in a series of posts examining claims in a Facebook meme I shared. Go here for the setup.

Claim 1: GMOs are safe.

What does this mean? It could mean that they are safe for human consumption: that eating food products from genetically modified organisms is as safe as eating comparable products from non-genetically modified organisms. It could mean that they are safe for the environment: that the use of genetic modification introduces no more risk for the ecosystem than the use of other agricultural technologies. It could conceivably also mean they are economically and socially safe: that GMOs do not pose a risk of (say) corporate exploitation of farmers, or other social ills, compared to non-GMO agricultural methods.

I will address the first two: health ecological safety. The third will, I think, fall under a later claim (about Monsanto).

Health

The first source I have found here is from the WHO (World Health Organization), an international group that has no apparent influence either from corporate interests that might promote GMOs beyond the evidence for safety, nor from organic corporate interests that might demonize them beyond the evidence for danger. Their mission is “to build a better, healthier future for people all over the world.” They have an FAQ that claims that all the GMOs tested so far “are not likely to present risks for human health.”

The second source, WebMD, is an online medical news and information site. Their mission “is to bring you the most objective, trustworthy, and accurate health information.” They claim to maintain journalistic integrity and independence, and I am not aware of any reason to challenge this claim. Their feature about GMO safety is quite long and detailed. They point out where GM technology falls on the continuum of agricultural practices throughout human history and prehistory. It is useful to note that we have been modifying our food – through selective breeding, cross-breeding, and other means – for millennia. They cite the American Medical Association, the WHO, and scientific studies supporting the safety of GMOs. They also note that the alternatives to GM technology are generally treatment with herbicides and pesticides, and techniques that accelerate the production of genetic variation (mutation) to enable the development of new traits by chance. They also point out that, biologically, there is nothing magic about genetically-modified organisms. They use the same chemical and biological processes to grow and reproduce. The way our bodies process them is the same. The only difference is that certain of their traits have been more precisely and deliberately introduced. Their conclusion is that GMOs seem to be as safe as the alternatives, though of course there is always room for more study.

I also came across an accessible peer-reviewed article from 2003, in the journal Toxicological Sciences. It is titled “The safety of genetically modified foods produced through biotechnology“. Here is the key conclusion: “The available scientific evidence indicates that the potential adverse health effects arising from biotechnology-derived foods are not different in nature from those created by conventional breeding practices for plant, animal, or microbial enhancement, and are already familiar to toxicologists. It is therefore important to recognize that the food product itself, rather than the process through which it is made, should be the focus of attention in assessing safety.”

Finally, there is a campaign by a group of nobel laureates called Support Precision Agriculture. They are all highly-accomplished scientists, so I think their pronouncements – especially en masse – about scientific claims carry some weight. However, they are not all experts in the relevant fields, so their statement is only valid to the extent that it relies on and agrees with consensus science in the field. It looks like this is exactly their goal: to amplify the signal of true science against a backdrop of propaganda from special interests (both the billion-dollar corporate organic lobby and the corporate pro-GM lobby). The campaign is intended to show that the science supports genetic modification as a safe technology with lots of promise to meet the needs of 21st-century agriculture. Perhaps the most persuasive part of their website, for me, is this graphic, which carries the headline “Is GM food safe? If an overwhelming majority of experts say something is true, then any sensible non-expert should assume that they are probably right.” It follows this with statements from 22 organizations representing scientists in medical, agricultural, and other relevant research areas. All of the statements support the safety of GM techniques in agriculture.

In an effort to explicitly seek out the other side, I searched for scientific evidence for dangers of GMO technology. I found several sources, most of which seemed to point to this 2014 article, titled “10 scientific studies proving GMOs can be harmful to human health”. The claim being made is clear from the title. However, in 2015, an molecular geneticist responded with an article on the Genetic Literacy Project website, titled “10 studies proving GMOs are harmful? Not if science matters”. Her article shows that these claims are overblown and unscientific. Several of the “studies” are not studies at all, but opinion pieces or other types of anti-GMO propaganda. One real study was retracted, and one was published in a journal that charges authors for publication (a practice that, in this case, calls its scientific validity into question). For the remainder, she cites controversy and a marked lack of consensus about the real implications of the studies.

I should note that the author of the rebuttal piece works for a biotechnology company (a fact that is openly disclosed at the foot of her article), so she is vulnerable to accusations of conflict of interest. However, to the extent that I understand and can independently reason about the arguments, her reasoning seems to be sound. For example, one of the claims against GMOs is that they can alter the DNA of the people consuming them. Remembering that a genetically-modified plant is still a plant, there is no reasonable mechanism by which they have more power to corrupt the DNA of animals that eat them than non-genetically-modified plants have. So the claim that GM plants are dangerous in this way is akin to someone worrying that flying in a plane (which defies the normal effect of gravity on our bodies) will affect your mass.

In summary, the best evidence I could find confirms the claim that GMOs are safe for human consumption. There may be some controversy in the scientific field, but I was not able to find a solid, empirically-supported contradicting the established evidence for their safety.

Ecology

 

So, what about their ecological safety? I found two applicable reports during my quick survey.

One, published in Advances in Biochemical Engineering/Biotechnology, is titled “Ecological impacts of genetically modified crops: ten years of field research and commercial cultivation“. It asserts that there is no evidence for ecological harm in the crops and modifications relevant to western and central Europe (maize, oilseed rape, and soybean).

The other is a report from the UK House of Commons Science and Technology Committee. They “concluded that any risk that genetically modified crops have been shown to pose derives from the trait displayed rather than any inherent risk posed by the technology itself.” (p54) In other words, genetic engineering adds no special risk, above the risks already posed by various agricultural products and practices. There are risks to monoculture, intensive agriculture, and indiscriminate use of certain chemicals – but these risks have nothing to do with genetic modifications. In fact, some of them may be mitigated by judicious and targeted genetic modifications.

Conclusion

The evidence overall seems very clear. Genetically modified crops are safe. They are safe to eat. They are safe for the environment.

More specifically, we have no reason to expect them to be less safe than the alternatives. All foods carry risks. We could choke. We could have allergies. We could consume them in ways that compromise our overall nutrition. We could produce them in unsustainable ways, compromising the agricultural land or the surrounding ecosystems. But none of these risks – as far as they have been studied – seem to be any greater for foods produced with careful genetic editing than those produced through selective breeding, accelerated mutation, or any of the other ways that we change our food’s genetics.

This isn’t to say that there’s no chance of danger. As with any knowledge, this is tentative and subject to revision pending further data. But to say that we should reject genetic modification just in case it turns out to be dangerous is no more rational than to say we should reject selective breeding just in case it turns out to be dangerous.

Anyway, I’ll end here. I’m sure you don’t all agree with this conclusion. If you have an empirically-supported objection to anything I’ve said, please let me know.

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