Following the Money
The Coca-Cola Company's Global Energy Balance Network, shut down in 2015, exemplified egregious conflicts of interest. The network funded research suggesting physical activity, not caloric intake, determines obesity—conveniently minimizing sugar's role. When internal emails revealed Coca-Cola's explicit control over research direction, the public backlash was immediate. But subtle conflicts persist more commonly and insidiously.
Nutrition research pervasively involves industry funding. A 2016 JAMA analysis found that 49% of studies examining sugar's effects were industry-funded; industry-funded studies were 5 times more likely to reach favorable conclusions toward sugar consumption than independent research.
The sugar industry's historical suppression of evidence parallels tobacco's tactics. Cristin Kearns unearthed previously confidential industry documents showing that in 1967, the sugar industry funded research downplaying sugar's link to heart disease while highlighting fat's role. This "sugar-funded attack on fat" influenced dietary guidelines for decades, shifting public concern from sugar to fat.
Dairy lobby funding similarly influences research. Studies examining milk consumption and bone health often receive funding from dairy organizations; such studies show more favorable results than independently-funded research. Grain industry funding shapes bread and cereal research outcomes.
Conflicts operate through multiple pathways: (1) researcher selection—companies fund researchers known to produce favorable findings; (2) study design—selective outcome reporting favoring industry products; (3) framing—emphasizing favorable results, downplaying unfavorable ones; (4) dissemination—ghost-writing; (5) interpretation—expert opinion shaped by undisclosed consulting relationships.
Ghost-writing is particularly problematic in nutrition. Pharmaceutical companies hire medical writers to draft manuscripts favorable to their drugs; academic researchers add their names, appearing to have conducted the work. Readers assume independent academic authorship when industry professionals shaped the narrative.
Finding funding sources requires detective work. Publications should disclose funding, but some studies appear in journals with lax requirements. Trial registries like clinicaltrials.gov often list sponsors but not all studies appear registered. Author declarations sometimes omit consulting relationships.
Websites like Project on Government Oversight (POGO) and Open Payments database (Centers for Medicare & Medicaid Services) document industry-to-physician financial transfers. Searching an author's name may reveal consulting fees exceeding their academic salary.
Industry-funded studies aren't invariably wrong. Industry-independent research can be poorly designed too. The key is recognizing that funding influences subtle aspects: which questions researchers ask, which confounders they adjust, which outcomes they emphasize, which comparators they choose.
Microbiome research increasingly involves probiotic companies funding studies. Pre-and Probiotics Association, International Scientific Association for Probiotics and Prebiotics, and major probiotic manufacturers fund significant research. This doesn't prove conclusions false, but it warrants scrutiny. Studies examining probiotic strain X funded by manufacturer of strain X deserve extra critical appraisal.
Better practice: Read independent systematic reviews and meta-analyses. These synthesize published research, addressing single-study bias. Cochrane reviews explicitly examine funding sources and often restrict meta-analyses to industry-independent trials. Journal requirements for funding disclosure are improving, but transparency remains incomplete.