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Food companies distort nutrition science. Here's how to stop them.

About a year ago, Marion Nestle finally got sick of the rotten state of nutrition science.

Everywhere she looked, she found glaring conflicts of interest. "Without any trouble, I could identify industry-funded nutrition studies by their titles," says the New York University professor. "It was so obvious."

Nestle kept seeing studies with very specific names, like, "Concord grape juice, cognitive function, and driving performance," or, "Walnut ingestion in adults at risk for diabetes." These papers were funded by the food industry — a grape juice maker, walnut growers — and nearly always reached glowing conclusions about the food in question. (Study: Concord grape juice can make you a better driver!)

Nestle had been researching nutrition long enough to know that there's rarely clear evidence that specific foods have such miraculous health effects. Healthy eating patterns can have a positive impact, yes. But independent researchers seldom discover that, say, a single food like walnuts can help stave off diabetes, as this study found.

Nestle was noticing a pattern. Studies sponsored by the food industry were far more likely to reach conclusions that favored the industry. They seemed more like marketing than science.

The problem of food research funded by food companies

"Drinking grape juice has brain boosting effects, even helping with everyday tasks like driving!" The study, published in the American Journal of Clinical Nutrition in 2016, was published by Welch Foods Inc.
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So Nestle decided to document the problem: On her blog, Food Politics, she began tracking all the industry-funded food and nutrition research she came across, paying particular attention to the number of studies that had positive results (i.e., favoring the funder).

Her findings so far are remarkable. Of the 168 industry-funded studies she has examined, 156 boast results that favor the funder. That's more than 90 percent.

The aforementioned research on Concord grape juice — which was supported by Welch Foods Inc. — found that drinking the product on a regular basis had amazing brain-boosting properties. (That study, of course, omitted any mention of the link between sugary beverages and obesity.) The study on walnuts, funded by the California Walnut Commission, concluded that consuming walnuts can help reduce the risk of diabetes. There are many, many more examples like this.

Nestle cautions that her tally is by no means exhaustive. It's entirely possible that there are many industry-funded food studies that don't favor their funders and she's just somehow missed them. It's also possible that a more careful peer review of her survey could identify errors.

But Nestle is not the first to notice this problem. Many nutrition researchers have been complaining about conflict-of-interest problems in their field for some time now. Whereas other fields, like medicine, have been putting in place safeguards to protect against undue industry influence, the field of nutrition has lagged behind in this regard.

And other research backs up Nestle's findings. Take this review of studies on sugary drinks. Independently funded studies tend to find a correlation between soda consumption and poor health outcomes. Studies funded by soda makers, by contrast, are less likely to find such correlations.

Or take this investigation of 206 publications on the health effects of milk, soft drinks, and fruit juices. Studies that were funded by beverage companies were four to eight times more likely to come to favorable conclusions about the health effects of those beverages.

"I think this is bad for nutrition research. It’s bad for public trust in nutrition science. It's misleading," says Nestle. "And it’s about marketing, not about science."

Why this absurd state of affairs has been allowed to persist

"Eating walnuts reduces the risk of diabetes!" The study, published in BMJ Open Diabetes Research and Care in 2015, was supported by the California Walnut Commission.
Sarah Turbin/Vox

I asked several researchers who work in food and nutrition what they thought about Nestle's tally. They all acknowledged that she was tapping into a real problem, one that's been difficult for their community to address.

So why are conflicts of interest allowed to persist in nutrition research?

One root cause is the need for funding. Right now nutrition science is relatively underfunded by government, leaving lots of space for food companies and industry groups to step in and sponsor research.

"If you look at the amount of funding available from the [National Institutes for Health], there's been a contraction of inflation-adjusted dollars available for research over the last decade," says Jason Block, a physician and researcher at Harvard Medical School. (Block has never taken industry money for research, mostly because of worries about conflicts of interest but also because he looks at nutrition policy issues that food companies tend to be less interested in sponsoring.)

"You have a lot of people in the field who are unable to get funding for the type of research they do through the government, so it causes them to look elsewhere," he adds.

Tradition also plays a role. "Nutrition science has always been close to producers," Dutch nutrition researcher Martijn Katan told me. "There’s such a direct interest in the outcomes of research for producers."

And food companies have ample incentive to promote this research. Under Food and Drug Administration rules, any health claims that they want to make on their packaging has to be backed up by scientific research. So the food industry has a keen interest in funding research — and favorable research that their profits may depend on.

Conflict-of-interest issues can also be more subtle

"People who eat more protein in the morning — like pork — manage their weight better!" The study, published in the journal Obesity in 2015, was funded by Pork Checkoff (the National Pork Board).
Sarah Turbin/Vox

Many people might imagine that conflict of interest in science works as a form of corruption. A food company pays a researcher for a favorable conclusion, and the researcher twists his or her results accordingly.

But it's often way more subtle than that. Often the researchers working with industry are good researchers who honestly believe their views. They may even have good reasons to work with food companies. The problem is that industry funding can elevate minority views and give them more prominence than they otherwise would have.

For instance, last year a series of reports in the New York Times revealed that a Coca-Cola-backed group was quietly funding researchers who downplayed the link between excessive calorie consumption and obesity. These researchers instead emphasized the dominant role of exercise.

There's no reason to think the researchers being funded are dishonest. But they are also a minority in the research community. (Most health and obesity researchers believe caloric intake matters way more than exercise.)

"People who eat pears are thinner and have better diets than non-pear eaters!" The study, published in the Journal of Nutrition and Food in 2015, was supported by the Pears Bureau Northwest and the USDA.
Sarah Turbin/Vox

This happens in food science all the time, Katan said. Certain perspectives will be elevated over others because they're better able to secure industry funding. Similarly, certain research questions are more likely to be explored because they attract the interest of industry.

There's good evidence, for example, that even small amounts of alcohol consumption by women increase the risk of breast cancer. But, says Katan, the alcohol industry has little interest in funding studies on this question. Instead, he notes, the industry prefers to fund research on how alcohol consumption reduces heart disease. (The evidence here is reasonably strong; it's just not the whole story.)

All that industry money going toward proving things we already know — like that fruits and nuts are healthy —€” also means real nutrition mysteries will remain unexplored.

I asked one of the industry-linked researchers, New Orleans cardiologist Carl Lavie, to comment on this issue. He conceded: "Industry will most likely want to fund researchers who are not biased against their products." In other words, the views that are most favorable to foodmakers are the ones that will attract the most research funding and the ones we're most likely to hear about.

"In the long term," Katan said, "the deepest harm being done is that it undermines the credibility of science. In the short term, it means some people will eat more butter or cheese than is good for them, and that it will take longer to get people off soda."

Nutrition research has to wake up to its conflict-of-interest problem

"Oatmeal suppresses appetite, increases satiety, and reduces the amount of calories people eat compared to the ready-to-eat cereal!" The study, published in the Journal of the American College of Nutrition in 2015, was funded by Quaker Oats Center of Excellence and PepsiCo R&D Nutrition.
Sarah Turbin/Vox

The field of medicine has similar conflict-of-interest problems. But, says Katan, major scandals — in which conflicted research led to noticeable harm and even patient death — helped the medical community wake up.

While the process is far from perfect, doctors and researchers have taken a number of steps to reduce the risk of bias and improve transparency, launching clinical trials registries (like ClinicalTrials.gov), as well as Sunshine legislation, which requires pharmaceutical and device companies to publicly disclose all the doctors they gave money to and in what amount.

It's these types of measures that the nutrition research community ought to embrace, says Harvard's Jason Block. "These should be full disclosure from the industry about whom they fund, and public disclosure of the main outcomes and hypotheses when starting observational studies, similar to what is done on ClinicalTrials.gov."

Nestle suggested industry could even pool contributions and appoint an independent committee to review research proposals — a view echoed by two public health researchers in a a recent debate published in the BMJ. "Previous work shows that dedicated manufacturer taxes, license fees, or legally mandated contributions (with the funds raised then administered independently from industry) are most likely to maximize transparency and minimize conflicts of interest."

So far, nutrition research hasn't faced the same kind of public scrutiny as medicine. But there are signs that that's slowly changing — particularly after big investigations like the New York Times stories on Coca-Cola and obesity. Following the Times's revelations, the soda maker took the incredible measure of publishing on its website most of the researchers and health outlets it had given money to over the past five years (though the fine print at the bottom of the list noted that Coke excluded some grant recipients that didn't permit the soda-maker to share their data).

None of the researchers I spoke to suggested we should abolish industry funding of food and nutrition studies. As Katan has written, these collaborations can lead to fruitful discoveries:

My personal experience makes me reluctant to support a blanket condemnation of industry-supported research, because collaboration with industry has allowed me to discover things that I could not have found otherwise. We discovered the effects of trans fatty acids on heart disease risk thanks to the expertise of Unilever, and the cholesterol-raising factor in unfiltered coffee thanks to Nestlé.

Instead, they wanted to see more awareness about the problem, more scrutiny of industry-funded research, and organized efforts to control conflicts of interest.

"It’s not the quality of the science that’s at issue," Nestle explains. "The studies are carried out according to strong scientific principles. But the bias seems to come in around the research question that’s asked, the interpretation of the results, putting a positive spin on findings even when the results are neutral." That's not good for science or for public health.


Editor: Brad Plumer
Images: Sarah Turbin

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