This post is part two of a two-part series on Coca-Cola’s funding of scientific research. Read part one here.
One study compared diet sodas to water as a strategy for weight loss—and found that the sodas were better. Another reviewed studies in which subjects switched from regular to diet soda to see if they lost weight. A third examined the methodology used in previous research that linked soda consumption to diabetes.
All came to conclusions favorable to the marketing desires of the Coca-Cola Company. And all were paid for by the company—or another organization closely allied with and financially supported by Coke.
But Coke didn’t just pay for these studies, which were conducted by academics and published in medical journals. The company also sent the results to officials at the Centers for Disease Control and Prevention, then met with them to discuss the studies and other matters, emails show.
Copies of the emails, released by the CDC in response to Freedom of Information Act requests submitted by U.S. Right to Know, show extensive contact between executives and allies of
Casting doubt on science
Marion Nestle, a professor of nutrition, food studies and public health at New York University, said the Coke studies are a “classic industry-funded ‘cast-doubt-on-the-science’ example” of a company sponsoring research to aid its marketing strategies and quiet criticism. Coca-Cola is interested in research that suggests that sodas don’t cause obesity or other health problems and that “any evidence to the contrary is so deeply flawed that it can be ignored,” Nestle said.
The first study Coke shared with the CDC found that obese people who drank diet soda lost more weight than those who drank water. Two of the authors were University of Colorado scientists, James Hill and John Peters, who had received funding from Coca-Cola. This paper, they acknowledged, was “fully funded” by the American Beverage Association, the soda industry’s trade group.
The second study was backed by the International Life Sciences Institute (ILSI), a “scientific organization” composed of food, agricultural and other companies, and conducted by researchers from the consulting firm Exponent. It reviewed multiple research reports and concluded that the best studies showed that switching from regular soda to diet sodas helped people lose modest amounts of weight.
Exponent has been criticized for consistently producing findings supportive of industries that hire it. Its research has been used to cast doubt on a relationship between secondhand smoke and cancer, to dispute a link between red meat consumption and prostate cancer and, in research performed on behalf of the National Confectioners Association, to suggest that frequent candy consumption doesn’t boost the risk of obesity.
“They serve whomever hires them,” Stanton Glantz, a tobacco researcher at the University of California San Francisco, said of Exponent. The Tobacco Industry Documents Library at UCSF shows that Exponent did work for Philip Morris, the tobacco company now known as Altria Group, as early as 1998.
"Factually wrong"
Angela Meyer, Exponent’s vice president of client services, said criticism by Glantz and others that the company is a hired gun “is quite simply factually wrong.” The firm is “well-known and respected for our high-quality work,” she said. The diet soda review, like most of its research findings, “was published in a reputable journal with rigorous peer review.”
The third study Coke officials shared with the CDC was a highly technical review of the strategies that researchers use when producing so-called meta-analyses—“studies of studies” that combine multiple related reports in order to maximize statistical power and reach stronger conclusions.
This review, fully funded by Coca-Cola, presented itself as a broad methodological examination of the criteria used to include and exclude studies from analysis. It used as its base example previously published meta-analyses that showed a strong link between the consumption of sugary beverages and the development of Type 2 diabetes. The authors concluded that if the original analyses had used the statistical techniques they were suggesting in their paper, those studies would have found a much weaker association between soda consumption and diabetes.
The Coke-funded research borrows from the strategy long used by tobacco companies to discredit scientific findings on the health effects of smoking, said Lisa Bero, a professor who directs the Bias and Research Integrity Node at the Charles Perkins Center of the University of Sydney, Australia.
“Attacking the methods of science is a common tactic of corporate interests to try to discredit research in a particular area,” Bero said. The tobacco industry “not only attacked the methods of individual papers but went so far as to establish their own ‘standards’ for research.”
Bero has done extensive work looking at the impact of funding on the outcome of research. She has found that studies of drugs, medical procedures and tobacco were far more likely to reach conclusions favoring industry sponsors than studies conducted by independent researchers.
In the soda arena, Bero says, researchers with financial ties to food companies were five times more likely to conclude that sugar-sweetened beverages had no impact on weight gain than authors with no financial links. And in a study published last year, she found that the results of studies looking at the health effects of diet soda were also highly related to the source of funding.
Bero and her colleagues looked at 31 studies on artificial sweeteners that examined both benefits like weight loss and their dangers such as diabetes. They found numerous problems with the studies.
Undeclared conflicts
Almost half had authors that failed to disclose their own conflicts of interest. Those who received funding from a sponsor were seven times more likely to reach conclusions that were favorable to the use of the sugar substitutes. None of the nine studies whose authors had no conflicts of interest came to favorable conclusions.
“It's important to be critical of reviews that are funded by any food- or beverage-related companies,” Bero said.
In a note accompanying the paper in the journal Systematic Reviews, the authors acknowledged that they’d received funding from Coca-Cola but stated that decisions about the content of the manuscript “including the design, analysis and interpretation—rest solely with the authors.”
In June 2014, one month before the paper was published, Coca-Cola and CDC officials met at the CDC campus in Atlanta. Emails between the two groups make it clear that among the issues discussed were the research findings of these papers. A couple of days later, Coke executives sent CDC officials a copy of the “draft manuscript” of the Systematic Reviews paper, cautioning them that they shouldn’t share it since it wasn’t yet published.
In the same email exchange, the two sides express their mutual appreciation.
“Thank you…for taking the time to meet with us,” wrote Beate Lloyd, Coca-Cola’s senior director of nutrition to Janet Collins, CDC’s director of nutrition, physical activity and obesity. “There are clearly areas where we can work collaboratively.”
Collins promptly wrote back. “We enjoyed it and learned a lot,” she said. “We also look forward to thinking about other areas of mutual interest and continuing our discussions.”
