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Genetically engineered crops – safe for humans and animals

For the past few years, I’ve posted nearly 50 articles here discussing the relative safety of genetically engineered crops. I’ve debunked myths. I’ve written about massive studies that show that they are safe for humans and animals, and, frankly, also for the environment.

I’ve also discussed the broad scientific consensus that supports the safety and usefulness of genetically engineered crops. This consensus derives from the best scientific minds in genetics, agriculture, botany, biomedical sciences, and many other areas of science germane to this topic.

And no different than the climate change deniers, who reject the broad scientific consensus on anthropogenic climate change, the anti-GMO activists reject science for any number of logical fallacies, and cherry picking of the science that supports their preordained beliefs. Many of us believe that the anti-GMO crowd are the left’s version of climate change deniers.

A new report has reviewed 900 studies and data since genetically modified crops were first introduced. And what did they find? Genetically engineered crops are safe.

Genetically engineered crops – NAS report


The National Academy of Sciences (NAS) is a private non-profit organization in the United States. Members are elected annually by current members, based on the candidates’ distinguished achievements in original scientific research. Election to the NAS is considered one of the highest honors in the world’s scientific community. The academy’s members serve as “advisers to the nation” on science, engineering and medicine. They do this without being paid for their activities.

The NAS is tasked withproviding independent, objective advice to the nation on matters related to science and technology. … to provide scientific advice to the government “whenever called upon” by any government department. The Academy receives no compensation from the government for its services.”

The NAS has over 2200 members from the USA, with another 400 from outside of the country. About 10% of the members have won Nobel Prizes. The NAS is made up of the elite of the scientific community – individuals, recognized by their peers, who are celebrated for their achievements in and commitments to scientific research and education.

The NAS recently issued a report (you can download a pdf version for free, but you will have to register with the NAS) that clearly concluded that genetically engineered crops are safe for humans and animals to eat. It also claims that GMO crops have not caused increases in cancer, obesity, gastrointestinal illnesses, kidney disease, autism or allergies.

More than 50 scientists, researchers, and agricultural industry experts participated in writing the 388-page report. They began work two years ago, and they reviewed more than 900 published studies (and the data for those studies) covering the 20 years since genetically modified crops were first introduced.

Think of this study as the highest quality meta-review, studies which are at the very peak of the hierarchy of scientific evidence. This review utilized the expertise of 50 of the top biotechnology scientists in the world, working at probably the most prestigious scientific institution in the world, examining every study ever written about the safety of GMO crops.

This thorough and systematic review of genetically engineered crops examined a large number of issues that have arisen about GMO crops. Even the non-profit watchdog group, the Center for Science in the Public Interest, which advocates for food safety and better nutrition, has been very positive about the report.

Gregory Jaffe, Director of Biotechnology at the group, in a public statement, said,

[infobox icon=”quote-left”]One of the report’s most significant findings is that there are no food safety or human health impacts from eating foods and ingredients made from currently engineered crops. That should give consumers confidence about the safety of eating foods that have those ingredients[/infobox]

Let’s look at what the researchers found:

Agricultural productivity

The study found that genetically engineered crops saved USA farmers money, in that it was cheaper to raise food crops than non-GMO crops. However, it did not appear that GMOs increased crop yields – the lower costs probably result from lower agricultural losses to pests and lower use of various pesticides and herbicides.

For example, pest-resistant crops that effectively poison insects as a result of a gene transferred from the soil bacterium Bacillus thuringiensis (Bt). These crops allow farmers to use far less pesticide than might be typically required.

In addition, farmers can manage the risk of those pests evolving resistance by using crops with high enough levels of the toxin and planting non-Bt “refuges” nearby. In other words, scientific research not only has given us a crop that needs less pesticide, but also given farmers a method to reduce resistance.

Overall, the report found that GE crops save farmers money in terms of time spent tilling and losses to weeds and insects, but can have both positive and negative effects on pests, farming practices and agricultural infrastructure. The report stressed the importance of following environmental best practices when employing GMO crops.

Effect on environment

The report described that genetically engineered crops have lowered pest populations in some areas, especially the Midwest. There was no evidence that these crops have affected the population of monarch butterflies, a claim that has morphed into an anti-GMO trope during the past few years.

The report also provided significant evidence of the development of resistant pests and weeds when GE crops have not been used in a sustainable manner. As stated above, following the best standards for crop planting, many environmental issues can be prevented.

The study authors issued a consensus opinion on the environmental issues with GMO crops:

[infobox icon=”quote-left”]Overall, the committee found no conclusive evidence of cause-and-effect relationships between GE crops and environmental problems. However, the complex nature of assessing long-term environmental changes often made it difficult to reach definitive conclusion.[/infobox]

This is typical of science. The evidence today points to the conclusion that there is no causal relationship between genetically engineered crops and environmental issues. However, as the statement suggests, if evidence does appear then maybe it should be revisited. Don’t fall for the fallacies of the the precautionary principle – just because we haven’t uncovered data, doesn’t mean there is going to be data.

Human safety

The study authors took an ingenious method to examine the human health effects of GMO crops. They compared disease reports from the USA and Canada, where genetically engineered crops have been consumed since the mid-1990s with those in the UK and Western Europe, where genetically modified crops are not typically eaten.

What did they find? A whole bunch of nothing.

The authors found no long-term pattern of increase in specific health problems in the USA and Canada since the introduction of these foods in those countries. The results were similar to what was found in the UK and Western Europe.

What else did they find in this study?

  • No correlation between obesity and consumption of genetically engineered foods.
  • No correlation with Type 2 diabetes mellitus.
  • Celiac disease has increased in both the GMO consuming and non-consuming populations, so genetically engineered crops aren’t the causal factor.
  • No correlation between cancer incidence and the use of GMO or non-GMO crops. And since cancer incidence has been falling in the developed world, there could be even a negative correlation (though I doubt it).
  • Autism spectrum disorder is similar between the USA and UK, despite the differences in GMO consumption.

The report concluded that there was no pattern of higher human health risks between populations that consumed genetically engineered crops in foods and those that consumed conventionally bred crops.

The authors summarized the review of genetically engineered crops with human health:

[infobox icon=”quote-left”]On the basis of its detailed examination of comparisons between currently commercialized GE and non-GE foods in compositional analysis, acute and chronic animal toxicity tests, long-term data on health of livestock fed GE foods, and epidemiological data, the committee concluded that no differences have been found that implicate a higher risk to human health safety from these GE foods than from their non-GE counterparts. [/infobox]

Once again, there is a possibility that research will uncover some very rare condition related to one specific crop some time in the future. But the odds of that a vanishingly small, and, once again, it’s fallacious to fall for the precautionary principle.


And here come the critics


Despite the incredible academic credentials of the 50 or so scientists and researchers involved in this project, the anti-science crowd has attacked it with all of the gusto that the Republican Party attacks climate change science. It’s still amazing how they share tactics, but that’s another story.

Several groups, who are vehemently opposed to any genetically engineered crop, attacked the report for arriving at “watered-down” scientific conclusions. Oh, and using the shill strawman argument, they claim, without any evidence whatsoever, that the report had undue “industry influence.”

This is the strategy of any anti-science group. Don’t provide evidence, probably because they lack it, but go for the ad hominem attacks.

For example, Food & Water Watch, a government accountability group in Washington D.C., attacked the NAS report, not by using contradictory scientific evidence, but on vague claims of conflicts of interests and the independence of the scientists. Because, we have vast bundles of evidence that shows the best scientists on this planet are all corrupt.

I get tired of this fallacy. Bring evidence is what I say.

The TL;DR version


Technically, genetic engineering has been around since the advent of agriculture, when we first domesticated crops. All humans have done is speed up the process of natural mutations, by just finding the genes it needs, and inserting them into plants. Maybe that seems unnatural, but nature holds no special characteristics over human manipulation, unless you adhere to the Naturalistic fallacy, that is “natural is better.”

And more than that, the robust consensus of real scientists with the credentials and expertise to know states pretty clearly that genetically engineered crops are safe for humans, the environment, and for farmers.

GMO crops give us a way to feed the world by reducing losses to pests, thereby decreasing the costs of producing foods. They are good for humanity as a whole.

Sure, someone is going to conflate Monsanto blah blah blah with GMOs, so GMOs are evil. Bring scientific evidence published in real journals that GMOs harm anyone. Then we’ll talk.

One of the leaders of the scientific research into GMO crops, Dr. Kevin Folta of the University of Florida, wrote a blog post about this study. His conclusions mirror mine:

[infobox icon=”quote-left”]We learned that GE crops pose no special risks over conventional breeding, that they help farmers by cutting costs and perhaps increasing yields slightly, despite no yield-associated genes being installed.  There is no evidence of effects on health for humans and animals, and environmental risks are understood and should be addressed.

We learned what we knew, and what we already teach.

The report also speaks of new ideas for a regulatory framework that makes a lot of sense. Every crop/gene combination should be weighed on its own merits and risks.

Is the report useful?  Yes.

The report synthesizes the existing science well and is an excellent reference. Scientists will find this extremely useful and the public will applaud a resource for accurate, vetted information.

But will it change minds?  No.  [/infobox]

Kind of like the massive evidence that humans cause climate change. Or that vaccines are safe and effective. Or that evolution is a scientific fact. it’s difficult to change minds even with evidence from the leaders of the scientific community.




Michael Simpson
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