The sugar industry's efforts to manipulate research on fluoride effectiveness and toxicity: A ninety-year history

BACKGROUND: Extensive academic research has documented the tobacco industry's manipulation of science. Recently, scholars have begun examining the sugar industry’s use of similar tactics to downplay sugar’s role in obesity, diabetes, cardiovascular disease, and tooth decay. Archival records show sugar-industry-funded scientists criticized evidence linking sugar to these harms and deflected attention to other risk factors. Sugar’s connection to tooth decay has been the most difficult harm for the industry to deny. Evidence is emerging that the industry turned to promoting fluoride as the solution to tooth decay thereby averting calls for reducing sugar consumption. Newly accessible sugar and dental industry documents enable investigation into whether fluoride research was manipulated to deflect from sugar’s role in tooth decay, and later to defend fluoride when evidence of fluoride’s own harmful effects arose. METHOD: Internal documents from sugar and dental organizations were examined and compared to the published scientific record. The Industries Documents collection at the University of California San Francisco was the main source of records. Analysis was in the context of the current understanding of how vested interests manipulate science to defend their products. RESULTS: Records dating back to the 1930s demonstrate the sugar industry, sometimes in cooperation with dental interests, exaggerated fluoride’s effectiveness and downplayed safety concerns. The sugar industry’s science manipulation campaign preceded the better-known tobacco industry campaign defending cigarettes. Key leaders of the sugar industry’s campaign transferred to the tobacco industry, which then adopted many of the sugar industry’s tactics and financed research from some of the same sugar-conflicted scientists. Currently, a prominent safety issue with fluoride is developmental neurotoxicity. Evidence indicates that researchers with undisclosed conflicts of interest with sugar and allied industries produced biased reviews downplaying this risk. CONCLUSION: Recently available records reveal a long history of the sugar industry distorting fluoride science. Many of the sugar industry's tactics were later adopted by the tobacco industry and mirrored by industries involved in asbestos, lead, pesticides, climate change denial, and others. Researchers and policymakers should be aware of the distorted scientific record regarding fluoride effectiveness and toxicity.