Public should be skeptical of industry-funded soft-drink studies, analysis says

A new study offers yet more evidence that research funded by the sugar-sweetened beverage industry is not to be trusted.

Researchers at the University of California, San Francisco (UCSF) analyzed 60 English-language studies conducted between January 2001 and July 2016 on the possible contribution of soft drinks and other sugar-sweetened beverages to the development of obesity and type 2 diabetes. Those studies included 28 clinical trials and 32 systematic reviews or meta-analyses of clinical trials.

Twenty-six of the studies (eight trials and 18 systematic reviews/meta-analyses) found no relationship between sugary drinks and the risk of becoming obese or developing diabetes, while 34 studies (20 trials and 14 systematic reviews/meta-analyses) did find a link.

The cumulative impression left by those studies — with 57 percent of them saying there is an effect and 43 percent saying there isn’t — is that the scientific evidence on the topic is inconclusive. And, indeed, that is precisely the argument that the sugar-sweetened beverage industry has made when combating “soda taxes” and other public-health regulatory efforts to curb the consumption of their products. 

But is that an accurate picture of the state of the research?

Not when you consider the financial interests of the people involved in the studies.

Evidence of manipulation

And that’s exactly what the UCSF’s authors did. They looked to see which of those 60 studies were either funded by the sugar-sweetened beverage industry or were authored by researchers who received money from them. 

The finding was startling. Of the studies that failed to find an association between sugary drinks and obesity and/or diabetes, 100 percent — 26 of 26 — had some kind of financial support from the sugar-sweetened beverage industry. Of the studies that did find a link, only 2.9 percent — one of 34 — had industry ties.

“We established that experimental studies that have financial conflicts with the [sugar-sweetened beverage] industry are much more likely than independently funded ones to find no relationship between [sugary beverage] consumption and metabolic outcomes,” the authors of the study conclude.

“This industry seems to be manipulating contemporary scientific processes to create controversy and advance their business interests at the expense of the public’s health,” they add.

Conflicts and caveats

As New York University food research Marion Nestle told the Los Angeles Times, “It’s way too simple to say that companies buy the results they want.”

But, she added, “there is something about funding that leads — almost certainly unconsciously and unwittingly — to skewing studies to get the desired results. This is not hard to do.”

The American Beverage Association has a much different take, of course. It dismissed the new analysis. “This paper is the latest in a trend of pro-tax forces writing speculative opinion papers to influence voters a week before a vote on several ballot initiatives to tax beverages,” the association said in a statement released to reporters.

Indeed, the UCSF study, which was published Monday in the Annals of Internal Medicine, could be construed as having its own conflict of interest. As the New York Times reports, the study is the result of a lawsuit brought by the sugar-sweetened beverage industry against the city of San Francisco, which in 2015 began requiring that billboards and other advertisements for sugary drinks carry warnings about their contribution to obesity, diabetes and tooth decay.

The city asked Dr. Dean Schillinger, the lead author of the new analysis and chief of the UCSF division of general internal medicine at San Francisco General Hospital, to put together a report on the scientific research regarding sugary drinks and health problems. While compiling that report, Schillinger noticed that results from industry-sponsored studies were significantly different than those from independent ones. That led him and his colleagues to conduct a more rigorous analysis.

An important reminder

The new analysis is not the only evidence, however, of the sugar-sweetened beverage industry’s efforts to create confusion around the issue of sugary drinks and health problems. As a study published last month in the American Journal of Preventive Medicine reported, dozens of national health and medical organizations — including several run by the federal government — have accepted money in recent years from the nation’s two largest soda companies, the Coca-Cola Company and PepsiCo.

“Previous literature suggests that sponsorships of health organization can have a nefarious impact on public health,” the authors of that study wrote. “Studies of alcohol company sponsorship and tobacco sponsorship suggest that corporate philanthropy is a marketing tool used to silence health organizations that might otherwise lobby and support public health measures against these industries.”

This latest analysis from the UCSF researchers is, therefore, just another important reminder for consumers: When any new scientific study is published, always consider the source — especially the source’s funding.

In other words, follow the money.

FMI: You’ll find an abstract of the study on the Annals of Internal Medicine website, but the full study is behind a paywall.