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Why it took the FDA nearly 40 years to ban trans fats

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The Food and Drug Administration is finally cracking down on trans fats, telling food manufacturers to remove them from all products within three years.

But for critics, the move comes too late: it comes nearly a decade after the evidence of harm was compelling enough that the FDA required food companies to label trans fat content on packaged foods, and half a century after scientific research started indicating that trans fats are artery cloggers that contribute to heart disease.

The lag between science and policy on trans fats is a fascinating case study in the weird world of health policy-making — and how scientists and industry lobbyists can inadvertently collude to cause unnecessary disease and death.

Evidence on the harms of trans fats has been mounting since the 1950s

Scientists first began sounding the alarm about the potential harms of artificial trans fats in the 1950s. Back then, researchers published a letter in the journal Science pointing to suspicious accumulations of trans fatty acids inside the arteries of people who died from heart disease.

"It was not definitive, but it suggested a potential problem you’d want to follow up on," says Kenneth Oye, a professor of political science at MIT, who has been studying trans fat science policy for a book he's writing.

While trans fat occurs naturally at very low levels in some meat and dairy products, researchers were worried about artificial trans fat. These are made when producers add hydrogen to liquid vegetable oil in order to harden it — a process called hydrogenation.

Man-made trans fats rose in popularity in the 1950s because they were relatively inexpensive to produce compared with solid animal fats, they increased the shelf life of food, they tasted good, and — at a time when other saturated fats like butter were vilified — they were billed as a healthy alternative. (Think margarine or vegetable shortening.)

Still, science was emerging that contradicted the healthy alternative narrative. By the 1970s, studies by Dr. Fred Kummerow at the University of Illinois suggested that pigs on diets high in trans fat had unhealthier hearts and more clogged arteries compared with those on diets lower in trans fats.

Another researcher, Mary Enig of the University of Maryland College Park, documented a correlation between higher levels of trans fat consumption and higher rates of heart disease in humans.

In 1976 came a pivotal moment that could have changed the story of trans fat forever, and likely saved thousands of lives. The FDA was trying to determine whether artificial trans fat should be considered "generally recognized as safe for human consumption" — a designation it gives to food and food additives based on the available research evidence.

"They contracted the decision out to the Federation of American Societies for Experimental Biology," explained Oye, "and the group determined that 'there is no evidence in the available information on [artificial trans fats] that demonstrates or suggests reasonable grounds to suggest a hazard to the public.' "

"When you have studies before that [suggesting potential danger]," Oye added, "it’s scandalous that they came to this conclusion."

Industry blocked negative science on trans fats


(AN NGUYEN/Shutterstock)

For Oye, the policy lag can be attributed to a couple of other things. First, the early FDA ruling that trans fats were safe influenced science policy for years to come. (The FDA only this week finally designated these lipids not "generally recognized as safe.")

Then there was the "systematic industry involvement," in his words.

In the '80s, scientists employed by Kraft and Procter & Gamble — Dr. Thomas Applewhite and Dr. J. Edward Hunter — would routinely unpick and cast doubt on the emerging science of trans fat's health harms, often in journal articles.

The pair would also work behind the scenes, according to investigative reporter Nina Teicholz, finding ways of getting papers that were critical of trans fats reviewed negatively in the pre-publication academic peer review process. As one colleague of Applewhite's said, "Protecting trans fats from the taint of negative scientific findings was our charge."

Kummerow, who is now  100 years old and a professor at the University of Illinois, conducted the early research on cadavers and pigs. And he says he often found himself battling an industry-driven narrative. "Industry scientists told the FDA trans fats were okay," he told Vox. He said everyone who disagreed either couldn't get research funding or found themselves derided by their peers.

Scientists had trouble accepting the anti-trans fat findings

trans fat junk food


Inspired by Kummerow's early findings, Walter Willett — chair of the department of nutrition at Harvard School of Public Health — began his research on artificial trans lipids in 1980.

In a study of more than 100,000 women, Willett tracked trans fat consumption and its link to outcomes like heart disease and death.

"After eight years, we saw a striking increase of heart disease risk [in the group that ate the most trans fat]," he told Vox. Those findings were published in the medical journal The Lancet in 1993.

But Willett said he had a hard time getting that research published. According to him, this was due to the scientific community's unwillingness to accept new evidence that defied common thinking at the time.

"There was a lot of resistance to the idea that trans fat might be a problem because of the recommendations — from the American Heart Association and other groups — telling people to eat a lot of margarine and Crisco, which is high in trans fat," he explained. "It was hard to swallow that trans fat could be worse than lard and butter."

Another study at the time, published in the New England Journal of Medicine, found that people who ate more trans fat had increased levels of bad (LDL) cholesterol and decreased levels of good (HDL) cholesterol. (Interestingly, that study was funded by Unilever, which happened to be producing the only margarine that was trans fat-free.)

By 1993, available evidence was compelling enough that the science advocacy group, Center for Science in the Public Interest, began urging the FDA to label trans fats on foods.

But it would still be years before regulators and the scientific community changed course. "Many people had based their whole careers on a campaign against saturated fat," Willett added. The gap between the research and regulatory changes was "not just about commercial interest but about human psychology."

That was also the experience of Kummerow, the researcher who published the early studies on cadavers and pigs.

"At meetings, when I gave my reports on [my findings], I would have a lot of scientists give me a hard time about what I was saying," he told Vox. "Industry scientists told the FDA trans fats were okay. The American Journal of Clinical Nutrition, for example, twice called other scientists together [to make a statement on trans fats], and the conclusion always was, 'We have to do more research.' I was never asked to be on those panels."

In 2013, Kummerow finally sued the FDA for not acting on the evidence sooner.

With the FDA ban, he thinks science finally won out. But he worries that industry is still having an influence, pointing to the fact that the regulatory agency gave food companies three years to phase out trans fats.

After the centenarian's lifetime of gathering evidence on trans fat's health harms, he says he wishes the FDA didn't wait another three years.

Correction: A previous version of this story misstated Kummerow's university affiliation.

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