Winter 2017

Good to Grow

Studies find no more health risks from genetically engineered crops than from conventional ones, but we cannot abandon other plant-breeding methods.

By Laura Ferguson

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Associate Professor Timothy Griffin, who researches the intersection of agriculture and the environment, worked with farmers when GE crops became available in the late 1990s. Photo: Kelvin Ma

A group of eminent scientists found that genetically modified foods are safe to eat, but noted that it has become increasingly difficult to distinguish between genetic engineering and conventional plant breeding and their effects 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 two years doing an exhaustive review of 900 research publications about genetically engineered (GE) foods for a study commissioned by the National Academies of Sciences, Engineering and Medicine. In addition to the literature review, the committee of scientists sponsored public meetings and webinars.

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 scientists’ 400-page report focused on all genetically engineered products, but contains the most detail on corn, soybeans and cotton. These three commodities consume the biggest acreage and account for almost all commercial GE crops; they also have been the subject of the most published research.

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

Tufts Nutrition: 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.

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.

The committee examined studies that found that 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.

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.

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

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.

Our 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.

Contact Laura Ferguson at

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