(CN) – The belief that genetically modified foods are harmful to human health has increased over the last two years to about half of all American adults, primarily among those with low levels of scientific knowledge, according to a new study published Monday.
But there was no shift in beliefs about GMOs among those with high levels of scientific knowledge. In this group, 38 percent of respondents said GMO foods were bad for their health, up just one percentage point from 2016.
Lead study author Cary Funk attributed the shift among Americans with low scientific knowledge to a limited understanding of GMOs.
“There is a longstanding idea among scholars that public awareness of the science behind genetic engineering is limited and thus public opinion might be ‘soft’ and more likely to shift over time,” Funk, who oversees Pew's science and society research, said by email. “The pattern in the new Center survey is consistent with this idea.”
Researchers also looked at attitudes about foods containing three other types of additives: meat produced with hormones or antibiotics; food grown with pesticides; and food containing artificial ingredients, like artificial coloring and preservatives.
They found people who “care deeply” about GMOs were more likely to believe foods produced with these additives posed a substantial risk to human health.
For example, 78 percent of those who cared “a great deal” about GMO foods said food additives posed a serious health risk, compared with 28 percent of those who cared less about GMO foods or not at all.
And 66 percent of those who “cared deeply” about GMO foods said meat produced with antibiotics or hormones posed a serious health risk, compared with 12 percent of those who cared less about GMOs or not at all.
Similarly to GMOs, respondents’ views about the health risks of food additives tended to correspond with their levels of scientific knowledge. For example, 43 percent of those with low levels of science knowledge said eating fruits and vegetables grown with pesticides carries a high risk to health over a person’s lifetime. Only 20 percent of respondents with high levels of science knowledge said the same.
Women were more likely than men on average to be concerned about the potential health risks from food additives and genetically modified foods.
Dietram Scheufele, a science communication expert at the University of Wisconsin-Madison and at Madison's Morgridge Institute for Research, doesn't believe limited knowledge of genetic engineering accounts for the shift in attitudes about GMOs. He noted only two of the nine questions used by Pew's researchers to measure scientific knowledge referred to genetics.
Rather, Scheufele – who was not part of the study – said the results show the American population “is split into two groups: people who believe scientific consensus and people who don’t."
“It’s not that people who score higher on these knowledge quizzes have necessarily learned the facts behind science, it’s that they have learned to defer to scientists when it comes to looking for the best factual evidence one can find,” Scheufele said by email.
“[W]hat this captures is what many scholars call deference toward scientific authority or the cultural authority of science,” he said. “In other words, most people don’t understand how genome editing works, or how climate modeling can help us trace the origins of man-made climate change, or how nanotechnology helps us create materials that don’t exist in nature. Instead, people who think GMOs are safe know that science is society’s best way of understanding the world around us."
Meanwhile, University of Idaho statistician Bill Price – also not part of the Pew study – said Pew's results were "overstated." Its survey questions appeared to reference genetic engineering, which can elicit biased responses, he said; similar studies that don't reference genetic engineering have found only a small percentage of Americans were concerned about GMOs.
In one study from Rutgers University looking at public perceptions about GM foods labeling, only 7 percent of respondents identified GM foods on their own when asked what information they want to see on labels. When later asked how important it was to them to have GM ingredients identified on food labels, 59 percent of respondents said it was extremely important.
"When you ask a question where you're specifically referencing GMO, genetically modified food, organic, nuclear, those will have a knee-jerk reaction; people are conditioned to respond to those" a certain way, Price said by phone. "These results don't really surprise me the way the question was asked."
Pew also found the number of Americans who said organic produce is more nutritious declined from 55 percent in 2016 to 45 percent in 2018. The shift occurred among those with medium and high levels of scientific knowledge.
Fifty-one percent of respondents said in 2018 organic produce doesn't provide a health advantage over conventionally grown produce. Just 3 percent said organic produce is worse for their health.
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