Nutritional Pearls: Consider the Source—of Funding

John is a 46-year-old man who is struggling to lose weight. He recently switched from drinking regular soda to diet soda, citing study results he heard about on the news that claimed that switching to drinking diet soda is associated with more weight loss than switching to drinking water.

How do you advise your patient?
(Answer and discussion on next page)

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Answer: Industry-sponsored studies tend to favor the industry.

When people find out about my interest in diet and nutrition, they sometimes seem to be surprised that I am an evidence-based physician. I don't tout fad diets. I don't think carbohydrates are bad for you, and I certainly don't think wheat is bad for you, unless, of course, you've been formally diagnosed with Celiac disease. And when I say "evidence-based" I don't mean that I'll pick only the studies that support my point of view and I certainly don't mean evidence that comes from research that is not well-designed, peer-reviewed, and published in a reputable journal.
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Unfortunately, when a lot of money is at stake some companies or industry associations do their utmost to sway public opinion by essentially buying scientific "evidence," sometimes in fairly subtle ways. Just 2 years ago, a study purported to show that drinking diet soda would help you lose more weight than if you drank water. This made a big splash in the news, as you might expect, but the study was fully funded by The American Beverage Association (which includes Coca-Cola, PepsiCo, and Dr. Pepper Snapple Group.

The Research

In a recent issue of JAMA Internal Medicine, a team of researchers performed a meta-analysis of published articles that compared the quality and outcomes of nutrition research that had been at least partially funded by industry with similar studies that had no such sources of funding.

Of the several hundred articles they assessed for relevance to their inquiry, only 8 articles, which included 340 studies, could be included in their analysis. For the purposes of this research, the authors chose to focus on whether industry sponsorship had an effect on whether the results were for or contrary to the industry's interests, whether those results were clinically significant, and how large those effects might be.

The Results

In the question of whether the results were for or against the industry's interests, the authors note that there are really 2 types of outcomes: it's not just whether the product or diet is good for you, but also whether that product or diet produces harm. Thus, results that are in line with an industry's interests might be positive (in the first case) or result in a lack of a negative (the second case). They found that overall, while industry-sponsored studies tended to favor the industry, the difference between industry-sponsored and non-industry-sponsored studies was not clinically significant. Further, industry-sponsored studies appeared to be of better overall quality than those studies not receiving funding.

That said, when authors of the analyzed studies disclosed the existence of conflicts of interest (for example, when a study author has been paid to do other work for that industry), 100% of the time the outcomes of that research was favorable to the industry. When there were no conflicts of interest, the outcomes were favorable only 76% of the time.

What’s the “Take-Home”?

Industry influence is not limited to affecting the outcomes of the research, however: funding can also help decide what questions are asked, and how; whether the questions are asked at all; whether the research, once completed, is even published (and where); and can even extend to how those outcomes are interpreted, not just by the scientists themselves but also by the media. I hope this study is just the beginning of ongoing inquiries into the effects that industry might have on nutrition research.

Reference:

Chartres N, Fabbri A, Bero LA. Association of industry sponsorship with outcomes of nutrition studies: a systematic review and meta-analysis. JAMA Intern Med. 2016;176(12):1769-1777.