Fructose Metabolism in Liver Disease

Excessive fructose consumption has emerged as a potent driver of liver injury through its unique metabolic handling in hepatocytes. Unlike glucose, fructose is rapidly phosphorylated by ketohexokinase (KHK) in the liver, bypassing key regulatory glycolytic steps and fuelling de novo lipogenesis. The generation of fructose-1-phosphate depletes cellular ATP, elevates uric acid and induces oxidative stress, thus sensitising the liver to inflammation, insulin resistance and steatotic changes. In addition to direct hepatic effects, fructose intake perturbs inter-organ communication by altering gut barrier function and microbiota composition, promoting endotoxaemia and further hepatic injury. Cumulatively, these processes underpin the progression from simple steatosis to non-alcoholic steatohepatitis, fibrosis and even hepatocellular carcinoma. Recent advances have begun to elucidate how endogenous fructose production via the polyol pathway, modulation of inflammatory signalling in non-parenchymal cells and crosstalk with extra-hepatic tissues contribute to the global burden of fatty liver disease.

Research from Nature Portfolio

Recent studies have illuminated the impact of fructose on immune and inflammatory pathways that may exacerbate liver disease. One investigation demonstrated that fructose reprogrammes key metabolic circuits in mononuclear phagocytes, shifting cells towards glutaminolysis and oxidative phosphorylation to sustain pro-inflammatory cytokine production. This metabolic rewiring, driven by mTORC1 activation, reduces cellular flexibility to nutritional stress and amplifies systemic inflammation in response to endotoxin challenges. While conducted in immune cells, these findings underscore fructose’s broader role in priming hepatic and extra-hepatic inflammation, a pivotal driver of non-alcoholic steatohepatitis.

Fructose Metabolism in Liver Disease publication trend

The graph below shows the total number of articles in fructose metabolism in liver disease across all publications each year (not limited to Nature Index journals).

Technical terms

Ketohexokinase (KHK): The rate-limiting enzyme that phosphorylates fructose to fructose-1-phosphate in the liver.

De novo lipogenesis: The metabolic pathway converting carbohydrates into fatty acids within hepatocytes.

Polyol pathway: A metabolic route converting glucose to sorbitol and fructose via aldose reductase and sorbitol dehydrogenase.

Gut microbiota: The community of microorganisms in the intestine influencing nutrient metabolism, barrier function and immune responses.

Uric acid: A by-product of fructose metabolism that can promote oxidative stress and enzyme activation in hepatocytes.

References

1. Uric Acid Stimulates Fructokinase and Accelerates Fructose Metabolism in the Development of Fatty Liver. PLOS ONE (2012).
2. Fructose and NAFLD: The Multifaceted Aspects of  Fructose Metabolism. Nutrients (2017).
3. Fructose: A Dietary Sugar in Crosstalk with Microbiota Contributing to the Development and Progression of Non-Alcoholic Liver Disease. Frontiers in Immunology (2017).
4. Fructose reprogrammes glutamine-dependent oxidative metabolism to support LPS-induced inflammation. Nature Communications (2021).
5. Uric acid activates aldose reductase and the polyol pathway for endogenous fructose and fat production causing development of fatty liver in rats. Journal of Biological Chemistry (2019).
6. Fructose Induced Endotoxemia in Pediatric Nonalcoholic Fatty Liver Disease. International Journal of Hepatology (2014).