A research biologist takes tissue samples from genetically modified corn plants inside a climate chamber housed in Monsanto agribusiness headquarters in St Louis, Missouri. (Photo: Brent Stirton/Getty Images.)

Americans with low levels of science knowledge are more likely to mistrust food additives and genetically modified foods, according to a new survey from the Pew Research Center.

This is one of a few major takeaways from the report, which surveys Americans' attitudes toward the risks certain foods pose. The researchers estimate that about half the country feels that food additives pose a serious risk to health over time (51 percent) and a similar number feels that genetically modified food is worse for health (49 percent).

Unsurprisingly, people's food ideologies—their feelings about what foods are good and bad and what food can do to or for a person—inform their feelings about genetically modified food and food additives, as well as their thoughts on diet and health. Across the board, however, women are slightly more likely to mistrust additives and genetic modification in food. That's especially consequential because, across the country, women are more likely to influence what families eat, either as mothers or as other caregivers.

The other major predictor of how people feel about additives and genetic engineering is their level of science literacy. The Pew study included nine general science knowledge questions, and based on the responses of those surveyed, about a quarter of Americans (26 percent) have a low level of science knowledge, compared with 49 percent with middling knowledge and 24 percent with high knowledge. The lower levels of science literacy are associated with higher levels of perceived risk: 43 percent of the group with low science understanding said that pesticides on produce pose a great deal of risk to a person's health over time, while only 20 percent of the group with high science literacy said the same thing.

A different Pew study found that most Americans believe scientists are split on the safety of genetically modified food, even though that's not the case (the American Association for the Advancement of Science and the National Academies of Science, Engineering and Medicine, among others, say they're safe to eat). Some have pointed to the back-and-forth coverage of health and diet science as a reason for the uncertainty, although in a 2016 Pew study on genetically modified organisms (GMOs) and food, 66 percent of respondents called this whiplash good science. But for most people, these attitudes are malleable and not strongly linked to party affiliation or identity—what researchers call "soft" beliefs. Broad food ideologies, like attitudes about health, fitness, and ideal diets, cut across political affiliations, gender, and race lines. The researchers mention that the landscape of food technology is in flux, and there's ongoing debate in the public sphere on the health effects of the modern diet. As leaders and influencers in the dietary world change their positions and recommendations, people's perceptions change too.

But even among those who have a high level of science literacy, it can be hard to know what, exactly, is in our food, and what the implications of those additives are. The Pew study asked people about foods with "genetically modified ingredients" to mimic common discussions, but exactly what that means is up for debate. In the United States, the Department of Agriculture has ruled that some gene editing is functionally the same as traditional crop breeding, and crops made with those procedures won't be called "genetically modified." But the European Court of Justice has declared that all gene-edited crops should be regulated as GMOs. Meanwhile, some of the most common additives have been common for decades, and many occur naturally in foods.

A concerning implication, the researchers note, is "chemophobia" among the general public—the irrational fear of "chemicals" as synthetic, man-made compounds that are bad for us. (Everything around us is made of chemical compounds.) Consumers tend to prefer "natural" food—a label without any standard definition in the U.S. regulatory sphere—and tend to worry that any addition to foods diminishes its "natural" qualities, but a substance's toxicity doesn't depend on where it comes from. Many natural substances are dangerous to human health, and many substances that are dangerous in large quantities are necessary in smaller doses. For example, formaldehyde is a known carcinogen, but our bodies also manufacture and metabolize it naturally as our cells make amino acids and other building blocks of life. Its presence in consumer products and vaccines alarms some consumers, but the level of exposure is so low there's no evidence of any harm. Even if you choose unaltered "all-natural" foods, you can't get away from it—formaldehyde is found naturally in milk, meat, and produce.