Study adds to growing evidence of the dangers of high fructose consumption
Fructose, a major component of sugar, directly causes macrophages and monocytes to manufacture more of the cytokines that promote inflammation, finds a study in Nature Communications. This study adds to the growing evidence that excessive fructose consumption could do harm.
Fructose has found its way into many foodstuffs as it’s a component of sugar and high fructose corn syrup, widely used in processed foods. In the US, say the study authors, fructose can account for 10% of calorie intake. High levels of consumption is already thought to contribute to obesity, fatty liver and type 2 diabetes, they explain. These conditions are accompanied by general inflammation in the body. The effects of fructose on other tissues and cells is not well known and so they decided to examine its effects on immune cells.
Researchers from the University of Swansea, University of Bristol and the Francis Crick Institute in the UK collaborated to do this research. They initially studied human monocytes and mouse macrophages cultured in fructose and glucose containing media and activated by exposure to lipopolysaccharide (LPS), a component of bacterial cell walls. The analysis of the metabolic pathways in the immune cells showed that the cells can metabolise fructose and that it switches them to use more oxidative pathways than when they are using glucose as their source of carbon and also causes them to break down glutamine. This metabolic shift directly fuelled production of a limited number of inflammatory cytokines by both sets of cells. The changes were a result of alterations in protein synthesis rather than alterations to gene expression.
The researchers also studied fructose’s short-term effects on mice. Groups of mice received 10% fructose or glucose or a mix for just 2 weeks and then were then challenged with a dose of LPS. The mice fed fructose showed an increase in cytokine levels consistent with the cell culture studies. The short term nature of the study, suggests that these effects of fructose on inflammation are independent of those seen in metabolic syndrome and related conditions, say the researchers.
Find out more
Search for fructose and (inflamm* or immune*)
Reference
Jones, N., Blagih, J., Zani, F. et al. Fructose reprogrammes glutamine-dependent oxidative metabolism to support LPS-induced inflammation. Nature Communications 12, 1209 (2021). https://doi.org/10.1038/s41467-021-21461-4