GMOs: Agricultural Improvement or Health Threat?

Researchers take a sweeping look at GMOs in our food supply

Posted Jun 08, 2016

At the grocery store or in the news, you've likely come across the controversy over products made with genetically-modified organisms, or GMOs. Scientific advances that use biotechnology to create plants that can resist disease and insects, offer higher yields and include additional nutrients have sparked fear among the public. The worry is that that genetically-modified foods will harm human health and the environment.

Food producers across the country are involved at some level. Ben and Jerry's — the popular ice cream maker — removed Hershey's Heath bars from its popular Toffee Heath Bar Crunch flavor last year to avoid GMOs in the candy bar. And earlier this year, Vermont became the first state in the nation to require food companies to label whether their products contain GMOs, after similar measures failed in other states, including California.

But, in fact, there is little evidence that GMOs are dangerous. Last week, the National Academy of Science, Engineering and Medicine released a 400-page report detailing what we know about GMOs. The research, authored by 20 of the nation's top agricultural experts, found no evidence that genetically-modified organisms are dangerous for human health or the environment.

In total, authors of the report reviewed more than 900 studies and papers. Evidence on the chemical composition of GMO foods showed no differences that would pose risks to human health and safety compared to non-GMO foods. And, in fact, some GMO foods have been modified to improve human health, such as rice with increased beta-carotene content to prevent vitamin deficiencies among people in developing nations.

The authors also found no evidence of environmental harms, such as less biodiversity near farms using GMOs. But they noted that assessing long-term environmental changes is complex and often requires a longer period of time.

Despite the conclusions in the report, some concerns remain. A 2014 meta-analysis found that breeding insect-resistant crops reduced the amount of insecticides growers use, a potential improvement for human health. But authors of the recent report also found some evidence that insects are adapting to become resistant to the GMO crops, a larger change that could have more sweeping effects on the environment.

Some scientists criticized the National Academy of Science report for failing to take into account how GMO crops impact the use of glyphosate-based herbicides. Essentially, large agricultural companies have bred some crops to resist the herbicide, commonly sold under the name Round-Up, so that they can use Round-Up to kill weeds without harming their crops.

Last spring, the cancer research arm of the World Health Organization declared glyphosate to be a probable carcinogen. In February, the FDA announced it would begin testing food products sold in the U.S. for glyphosate residue.  Engineering plants so that farmers can use more of these types of herbicide may pose a health threat.

But, the report cautioned, the reality is that each type of new crop — whether bioengineered or developed using conventional breeding techniques — must be evaluated separately to determine whether new characteristics pose a threat to human health or the environment.

The take-home message here is certainly complicated. While there is no evidence that consuming GMO foods harms human health, the larger impact on agricultural practices and the environment is not clear from the available evidence. The bottom line is, like many new technologies, the process of genetically-modifying crops can be helpful or harmful depending on how it is used.