- GMOs are foods that have had genetic material from another organism inserted into them.
- Thus far, research has found GMOs are safe to consume and do not cause illness or allergies.
- Common GMO foods in the US include corn, soybeans, potatoes, and apples.
- Visit Insider's Health Reference library for more advice.
For decades, scientists have been bioengineering foods like corn and soybeans to make them sturdier and safer from pests, among other traits.
Because GMOs are entirely new food products developed in a lab, many people are worried that they will harm their health, even though there's no evidence that they cause illness or disease. Here are the facts on GMOs and why they're safe to eat.
What is a GMO?
Genetically modified organisms (GMOs) have genetic material that has been altered in a way that would not happen in nature if left to grow on its own.
That's because scientists take DNA for a specific desired trait from one organism, and insert it into another. This is different from conventional breeding, a practice thousands of years old, where farmers breed existing crops to be bigger or to produce more grain. These methods take more time and produce less precise results.
GMO foods are engineered to be:
- Hardier. Scientists insert a gene allowing the plant to survive weed killers that farmers use to kill invasive plants and fungi. This gives the crops a better chance to grow and makes farmer's lives easier because they spend less time plowing and spraying pesticides everywhere.
- Insect-resistant. Plants receive a gene from Bacillus thuringiensis (Bt), a bacteria that kills certain insects before they have a chance to damage a crop plant's roots. This means farmers can use fewer pesticides and often have higher yields. About 82% of corn in the US uses Bt seeds.
- Faster growing. Genetically modified salmon (not yet available for purchase) has a gene that makes it grow to maturity in half the time of wild salmon. This should make this healthy food more easily available.
- Fresher. One variety of GMO apples doesn't brown after slicing, which may help prevent food waste. In the US about 31% of all food goes wasted.
- More nutritious. Golden Rice (not available for purchase) is a form of rice that helps prevent vitamin A deficiency, which can kill or blind children under the age of five, thanks to its higher vitamin A levels.
Are GMOs safe to eat?
So far, there is no evidence that GMOs harm human health.
One of the most comprehensive studies to date is one published in 2016 from the National Academies of Sciences, Engineering and Medicine. Researchers looked at 20 years of scientific research and found that among countries with wide adoption of GMOs, rates of illnesses were similar to countries with low adoption.
Further, the Food and Drug Administration, Environmental Protection Agency, and the United States Department of Agriculture regulate and test GMOs to make sure they are non-toxic and don't cause allergies or cancer, says Felicia Wu, PhD, distinguished professor of food science and human nutrition at Michigan State University.
Importantly, just because a food is genetically modified doesn't mean it is nutritionally different from any other food. "After modifications to its genes, a crop or food produces a new protein. But once we consume that protein, we break it down in our digestive systems into amino acids just like any other protein. It doesn't change our DNA," Wu says.
Benefits of GMOs include:
- Making farming more efficient: "GMOs reduce the amount of labor and chemicals that farmers need to use, making food less costly to produce," says Ruth S. MacDonald, PhD, RD, professor and chair of Food Science and Human Nutrition at Iowa State University.
- Possibly being better for the environment. For example, they require fewer insecticides. According to a 2018 study, they also reduce carbon emissions by the equivalent amount of removing 16.7 million cars from the road. However, the study was funded by Monsanto, one of the largest GMO corporations.
- Increasing food security. Crops that have been genetically engineered to have more nutrition, repel pests, yield greater amounts, and withstand drought can help feed a growing world population. However, there is some debate as to whether GMOs have delivered on this promise.
Potential drawbacks of GMOS include:
- Potentially reducing biodiversity: There is a risk that bioengineered crops can spread to and overwhelm wild species thus reducing an ecosystem's biodiversity, says Gerald Berkowitz, PhD, a professor of plant science at the University of Connecticut. This is important because genetic diversity helps organisms adapt to a changing environment.
- Lack of very long-term evidence: There is no evidence that GMOs hurt our health, but there is also a lack of very long-term human studies, since people have only been consuming GMOs consistently since the 1990s. Thus, a 2015 poll by Pew Research Center found that only 37% of people surveyed thought GMOs were generally safe to eat.
How to tell if foods contain GMOs
According to a new law, any GMO food or product in the United States must be labeled with "bioengineered" effective January of 2022. Meanwhile, the European Union already requires all GMO foods to have labels, though Canada does not.
Most corn and soybean crops in the US are genetically modified, so they are commonly found in the American food supply, especially in processed foods like cereal and chips. Other common GMO foods include:
GMOs have been engineered in a laboratory to have specific characteristics that make them resistant to pesticides and insects, grow faster, and stay fresher longer.
Most of the corn and soybean crops in the US are genetically modified, along with some produce and salmon.
Despite consumer worries, decades of research and evidence suggest that eating GMOs does not pose a risk to human health. Scientists rigorously study GMO safety, and a number of government agencies inspect their research to make sure GMOs are safe before humans or animals eat them.
However, if you are concerned about the environmental or health impacts, you can shop organic food knowing it will be GMO-free.