Fructose and metabolic disease: Bias in nutrition research

Non-alcoholic fatty liver disease (NAFLD), excessive fatty buildup in the liver, has a global prevalence of 25%, which parallels the increasing obesity and diabetes rates. This disease can lead to other complications such as cirrhosis, liver cancer, liver failure or cardiovascular disease. Evidence suggests diets high in sucrose and high fructose corn syrup increase the risk for NAFLD (Jensen et al., 2018).  Historically NAFLD has been thought to be a result from a sedentary lifestyle and over nutrition; however, recent clinical evidence indicates fat accumulation in the liver is due to an increase in lipogenesis and impaired fat oxidation due to fructose (Jensen et al., 2018). Over the years however, this evidence has been opposed by other nutrition research, specifically those funded by large food companies. Should we be regulating nutrition research more rigorously to prevent any bias?

Fructose, a simple sugar, is naturally present in fruit and honey but is also present in high fructose corn syrup, sweeteners and table sugar. There are differences in the metabolism of glucose and fructose. In a recent article published in the Journal of Hepatology, fructose was found to activate lipogenesis and decrease fatty acid oxidation, ultimately causing fat to build up in the liver. Several previous studies however found no association between fructose and metabolic disease. Many of these studies opposing the results were funded by major food companies including Nestle, Mars and Hershey. The food industry seems to have copied the tobacco industry when it comes to distorting science.

The results of these studies should not be influenced by any large companies. I think there is clearly a need not only for additional clinical trials and research to fully understand the exact mechanism of fructose, but also some tougher regulations on industry-funded research. Should industry-funded research even be allowed? I believe in some cases this funded research is good work, however I think there is plenty of evidence that industry-funded work can be biased.

Jensen, T., Abdelmalek, M. F., Sullivan, S., Nadeau, K. J., Green, M., Roncal, C., … Johnson, R. J. (2018). Fructose and sugar: A major mediator of non-alcoholic fatty liver disease. Journal of hepatology, 68(5), 1063–1075. doi:10.1016/j.jhep.2018.01.019

Kanerva N, Sandboge S, Kaartinen NE, Mannisto S, Eriksson JG. Higher fructose intake is inversely associated with risk of nonalcoholic fatty liver disease in older Finnish adults. Am J Clin Nutr. 2014;100(4):1133–8.

Maurice, J., & Manousou, P. (2018). Non-alcoholic fatty liver disease. Clinical medicine (London, England), 18(3), 245–250. doi:10.7861/clinmedicine.18-3-245.