The Bottom Line on Genetically Engineered Foods

The evidence is that they are safe, but other crop-breeding methods are important, too, says science panel

corn field near harvest time

In a new report, a group of nationally eminent scientists say that genetically modified foods are safe to eat, but they also note that it has become increasingly difficult to distinguish between genetic engineering and conventional plant breeding and their impacts on health and the environment.

Timothy Griffin, an associate professor and director of the Agriculture, Food and Environment program at the Friedman School, was one of the scientists who spent the past two years doing an exhaustive review of 900 research publications about genetically engineered (GE) foods for a large study commissioned by the National Academies of Sciences, Engineering and Medicine.

Genetically engineered foods—ones in which new genes have been introduced to develop a particular trait, such as resistance to pests or herbicides—have long been controversial and have generated a range of opinions, both pro and con. 

The report focused on all genetically engineered products, but contains the most detail on corn, soybeans and cotton. Occupying the biggest production area, they account for almost all commercial GE crops and have the most published research.

In addition to the literature review, the committee sponsored public meetings and webinars. The result is an extensive and nuanced 400-page report, released on May 17. A companion website aims to seed a national conversation about genetically engineered crops.

Griffin spoke with Tufts Now about the research, the report, and what it all means.

Tufts Now: Why did the National Academies decide to study this issue now?

Timothy Griffin: We’re essentially 20 years into the production of this small set of GE crops, and it has emerged, in some cases, as a polarizing issue. To date, though, there has been no consensus about impact; no one had assessed the evidence around different impact areas—agricultural, environmental, socioeconomic and human health.

“Our hope is that by doing this very thorough assessment of what we know—and what we don’t know—we can bring down barriers to understanding a very complex and important issue,” says Timothy Griffin.“Our hope is that by doing this very thorough assessment of what we know—and what we don’t know—we can bring down barriers to understanding a very complex and important issue,” says Timothy Griffin.
At the same time, the rate of change with regard to genetic engineering has been nothing short of remarkable. It’s interesting that concurrent to our study, the government is reviewing how products from these technologies are regulated.

What is your area of expertise, and why did you decide to participate on the committee? 

I’m broadly trained in agricultural science, particularly as it relates to crop production. I worked directly with farmers at the time these products started to become available in the late 1990s. I had some experience in how farmers make decisions and how different technologies might be useful to them.  

I had never been on one of these committees before, but I thought it was a good fit. It certainly is connected to what we do here at Friedman. This is a policy discussion, and some of the issues in the report are exactly what I talk about in class.

You probably heard some new perspectives as well.

Yes, and the report reflects that. We did not go out and just accumulate the science, and then say “here’s the science.” This report focuses on a much broader range of issues, including how people think about their food.

The committee examined studies that found GE foods are as safe as foods from non-GE crops for both people and livestock. But the report also strikes a cautionary tone about the long-term safety of genetically modified foods.

We looked at a lot of evidence and found no apparent health risk. We also heard from a number of speakers who talked about research both on potential health impacts and on perceptions—how people perceive different risks and benefits.

We looked at all this evidence and concluded that there doesn’t appear to be any negative impact. If there had been a clear signal, that would have been a very different story, but there wasn’t. But yes, that doesn’t say there never will be a risk—that’s why the cautionary tone. Policy and regulatory functions need to continue to look at these issues.

Regarding crop production, it’s interesting that you also widen the lens to focus not just on genetic engineering, but on conventional plant breeding, too.

The most notable GE crops are grown commercially and on a large scale—they include soybeans, cotton and corn. Those plants were developed by introducing a gene from another organism not related to the crop. In these cases, the genes are from bacteria that are inserted in plants to make them either insect resistant or herbicide resistant.

One statement in the report makes clear, though, that while this kind of genetic engineering has advanced in recent years, conventional breeding has to continue as well.

With some of the newer technologies, like gene editing, it’s unclear what the impact will be—that’s still an open question. Gene editing means that you modify or manipulate existing genes; you change the genome to achieve a desired trait, like disease resistance. You’re not adding new genes, which is what was done, for example, to develop herbicide resistant corn.

Increasing the yield of crops is the result of many, many traits, so conventional breeding has a very important role. Even though GE crops are grown on millions of acres, it is hard to disentangle the effect of genetic engineering from genetic improvement. Our report states that if you want yield to increase year after year after year, then you have to continue conventional plant breeding year after year after year.

Do you see genetic engineering going beyond the large crops—soy, corn and cotton?

Until very recently, traits targeted by genetic engineering have been all pest-related. They are what we call input traits, rather than output traits—like changing the composition of a grain.

In just the past two years, though, more new products are output-related, like apples and potatoes that don’t brown as quickly when they’re bruised. It will be interesting, in the next five to 10 years, to see the potential for genetic engineering to alter nutritional aspects of food crops or feed crops to make them healthier.

The report states that “new technologies in genetic engineering and conventional breeding are blurring the once clear distinctions between these two crop-improvement approaches.” It goes on to say that regulating new varieties should focus on a plant’s characteristics rather than the process by which it was developed. Talk more about that.

Right now there is a lot of attention focused on regulating the process. We have a special set of regulations that apply only when certain techniques are used. But the committee agreed that there is a blurring of the line between a range of techniques.

Genetic engineering, conventional breeding and newer technologies like gene editing all work differently, but the outcome might be genetically similar, with similar risks and benefits.

You could have a plant variety that is conventionally bred to be herbicide resistant and one that is genetically engineered to be herbicide resistant. It’s increasingly difficult to distinguish between the two processes. So that’s why we stated that regulatory agencies need to focus not on the process itself, but on the risk/benefit of the product, considering all the health and environmental impacts of those foods.

More than 60 countries, including Japan, China and those in the European Union, already label genetically engineered foods. Vermont has taken the lead in the United States by pushing for such labeling. The report concludes that mandatory labeling is not warranted for health reasons, but acknowledges that there are “value choices that technical assessments alone cannot answer.” Can you elaborate?

The idea is that there are multiple valid reasons why people might want products labeled. They might want labels because they want to decide for themselves if there is a health or environmental impact, or simply because they want to distinguish one product from another.

We say that the products that we are talking about appear to be safe, so there is not a need to label for health impacts. That is a separate decision. It could be voluntarily labeling or a certification program. It’s not clear if a single type of labeling would satisfy all consumers.

The chair of the committee made an interesting point when he spoke to the media, saying that he hopes that because the report is published on an interactive website, it “will open a conversation, not make some kind of proclamation.” Is it your view that the report will continue to be a resource for the public?

Yes. The committee wanted to be as transparent as it possibly could be by making it easy for readers to find the information they’re looking for, instead of paging through a 400-page report. We knew from the beginning that this was a contentious issue and that there would be a huge variety of viewpoints. Our hope is that by doing this very thorough assessment of what we know—and what we don’t know—and by putting it together in one place, we can bring down barriers to understanding a very complex and important issue.

Laura Ferguson can be reached at

Back to Top