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The Surprising Truth About GMOs


Edible Engineering

You scan food packages for fiber and whole grains, avoid added sugar, and wouldn't even think about buying something with trans fats. Just when you thought you had a handle on how to eat healthy, there's another worry to sort out: genetically modified organisms (GMOs). Some opponents would have you believe these ingredients, which are largely banned in Europe, are the dietary scourge of the decade. But how concerned should you really be?

Ninety-three percent of Americans surveyed say they want foods that contain GMOs to be labeled as such, according to a New York Times poll. And a number of companies are listening. Last year Whole Foods announced it would require all of its suppliers to label their foods and products for the presence of GMOs by 2018. Chipotle became the first national fast-food chain to disclose (on its website) which ingredients are genetically engineered. Trader Joe's now makes its private-label foods GMO-free. And Target has pledged not to carry AquAdvantage salmon, which would become the first genetically engineered animal on the market if it ever hits shelves (final FDA approval is pending). Meanwhile, "GMO-free" is the second fastest-growing health and wellness claim on store-brand food products, with dollar sales up 29 percent from 2013 to 2014, according to James Russo, senior vice president at Nielsen, the marketing research firm.

Clearly, many consumers are uneasy with the idea of so-called frankenfoods, which are grown from genetically altered seeds. Scientists typically clone a gene from one organism (such as a plant or bacterium) and combine it with the original plant. When this plant produces seeds, they contain the foreign DNA, which alters the plant's characteristics. Bt corn, for example, has been modified with a gene taken from a soil bacterium that allows the corn to produce a toxin that is deadly to corn earworms but not toxic to humans, fish or birds. Defenders of the biotechnology say GMOs are needed in order to double the world's food supply over the next 35 years as the population grows. Opponents argue the technology is profit-driven, risky, and short on promises. Three states -- Maine, Vermont, and Connecticut -- have passed GMO-labeling legislation, while voters in California and Washington rejected it. The issue will be on the Oregon ballot in November.

An NPR poll found that 64 percent of respondents were unsure if GMOs were safe to eat. Nevertheless, Americans have been consuming them for a couple of decades, often without knowing it: About 75 percent of processed foods already contain GMOs. That's because most of our two biggest commodity crops -- corn and soy -- is genetically engineered to repel insects or to withstand herbicides, and these crops are everywhere in our food supply (think high fructose corn syrup, corn oil, soy lecithin, and numerous other additives). Other common genetically modified crops include sugar beets, canola, alfalfa, the Hawaiian papaya, yellow squash, and cotton, which we consume in the form of cottonseed oil.

Beyond the Hype

Rumors that foods with GMOs are a health hazard and may be causing everything from immune disorders to allergies persist -- especially online. But they're simply not true, according to the American Medical Association and the American Association for the Advancement of Science (AAAS), among other esteemed groups.

"GMOs are probably the safest foods ever put in our food supply because they are the most tested," says biologist Nina Fedoroff, PhD, the past president of the AAAS and a member of the National Academy of Sciences. Fedoroff explains that farmers have long genetically manipulated crops through cross-pollination, combining the best features of two different plants to improve outcomes. The modern strawberry was the result of a North American variety meeting a South American one in 19th-century England, for instance. In the last century, agricultural scientists sometimes zapped plants with radiation to see if any useful mutations would result -- and they did, hence the ruby red grapefruit and the seedless orange.

After reviewing more than 130 research projects over 25 years, a report from the European Commission, which proposes legislation for the European Union, concluded that "GMOs are not per se more risky than ... conventional plant breeding technologies." Fedoroff argues that, in fact, GMOs are even safer than traditionally bred crops because they contain just one or two new proteins (encoded by genes) that are tested by the industry to see if they are toxins or allergens as compared to tens of thousands of never-tested proteins introduced as a result of traditional breeding. They must also be approved by the U.S. Department of Agriculture, the Food and Drug Administration and, when the plants release pesticides (such as Bt corn), by the Environmental Protection Agency.

"Safety just doesn't seem to be the issue," agrees Thomas Sherman, PhD, an endocrinologist and an associate professor of nutrition at Georgetown University Medical Center, pointing to extensive review studies from both Europe and the United States. "People don't seem to be forming allergic responses to genetic modifications so far." Health-conscious consumers, he says, might want to pay less attention to GMOs and more attention to whether food is organic (which, by definition, means it's non-GMO too). "That's a bigger issue for health, not so much in terms of nutrients, but in terms of the presence of toxins and hormones," Sherman says.

Sometimes genetic engineering aims to boost health. A private-public partnership has been working to develop "golden rice" to include new genes for beta-carotene, a precursor of vitamin A. In some developing parts of the world, children go blind because they are deficient in the vitamin, and enriched rice could help. Other engineered foods are merely convenient, such as the proposed Arctic apple (expected to be available by 2016) that doesn't turn brown when you cut it. That's unlikely to improve our health, Sherman notes, unless it makes more of us eat apples instead of cheese fries.

Risks and Concerns

It is conceivable, however, that nonfood genes used in GMOs could at some point cause problems. Douglas Gurian-Sherman, PhD, director of sustainable agriculture and senior scientist at the Center for Food Safety, argues that GMOs combine genes in wholly new ways, sometimes from organisms, such as some bacteria, that are not normally eaten by people. Health consequences would be difficult to predict. "We don't have well-understood or reliable tests for possible allergens from nonfood sources," Gurian-Sherman says. And he points out that current safety testing is not only voluntary but also performed by the food industry, not by independent scientists.

There are environmental repercussions as well. Thomas Sherman notes that genetically modified crops have the potential to spread into neighboring fields. "Once you let them into the environment, you lose all control over them," he says. "That's not necessarily bad, but you just don't know."

Plus, GMO crops sometimes lead to increased use of pesticides. For instance, "Roundup Ready" corn, soybean, and cotton are crops engineered by Monsanto, the world's largest seed company, to withstand the company's glyphosate herbicide (known as Roundup), which causes the weeds in the fields to perish. Glyphosate is considered a relatively safe chemical, and the idea was that farmers who sprayed it didn't have to plow up fields to get rid of weeds, thus conserving valuable topsoil. But less than 20 years later, over a dozen weeds have developed resistance to glyphosate, meaning that farmers have to use more of it, as well as other more hazardous chemicals such as 2,4-D, a powerful herbicide linked to reproductive problems and birth defects, says Chuck Benbrook, PhD, a research professor at Washington State University's Center for Sustaining Agriculture and Natural Resources. On the basis of 16 years of pesticide data, collected since GMOs were introduced, Benbrook predicts that use of 2,4-D will increase more than fourfold in the next decade, spurred by new GMO crops. "Twenty years from now we will look back and deeply regret the misuse and mismanagement of current-generation GMO technology," he says.

Monsanto says they are working with farmers to manage resistant weeds through other methods in addition to herbicides. And Jason Clay, senior vice president of the World Wildlife Fund, points out that crops will soon be specially engineered to require less water, withstand more heat, and produce bigger yields per acre, thereby requiring less land. "The bottom line is, if we take modern genetic engineering off the table, how are we going to produce twice as much food without expanding the land base twice as much?" he asks.

Ultimately, the controversy over GMOs may be a distraction from the bigger discussion of what a safe and sustainable food production system looks like. How can farmers be smarter and more strategic about pesticides? How can regulators better protect us from the overuse of antibiotics and growth hormones? As Melanie Warner, the author of Pandora's Lunchbox: How Processed Food Took Over the American Meal, sums it up: "GMOs are just one part of the critical conversation about the future of food."

GMOs at the Grocery Store

Even though GMO foods are generally considered safe, some people are choosing to reduce their consumption of them. If you'd like to do the same, follow this advice from Georgetown University's Thomas Sherman, PhD:

Eat more fresh produce and fewer processed foods. In the U.S., very few fruits or veggies are genetically engineered, with the exception of the Hawaiian papaya.

Eat more whole grains. Wheat, oats, and other grains don't (yet) come in GMO varieties.

Lower your sugar intake. A growing percentage (over 50 and counting) of commercial sugar comes from genetically altered sugar beets

Buy organic. USDA Organic certification means a product contains no GMOs, antibiotics, or hormones; it also rules out most synthetic pesticides and fertilizers.

Buy products labeled "non-GMO." These are certified by independent industry groups like the Non-GMO Project (, which conducts on-site visits and testing.