Dietary Sugars Alter Hepatic Fatty Acid Oxidation via Transcriptional and Post-translational Modifications of Mitochondrial Proteins.
Level 5 - mechanism / opinion, no new human data
Preclinical animal (mouse) experimental study
PubMed 31577934 · doi:10.1016/j.cmet.2019.09.003
What was done
Researchers fed mice a high-fat diet (HFD) supplemented with either fructose or glucose to evaluate divergent effects on hepatic mitochondrial function and fatty acid oxidation. They examined regulatory mechanisms including malonyl-CoA levels, mitochondrial size and protein abundance, acetylation of mitochondrial proteins (specifically CPT1a and ACADL), and the impact of knocking down fructose metabolism.
What was found
No quantitative numerical values were reported in the abstract. Both HFD and HFD plus fructose-fed mice showed decreased activity of CPT1a, the rate-limiting enzyme of fatty acid oxidation, whereas knockdown of fructose metabolism increased CPT1a and its acylcarnitine products. Fructose-supplemented HFD specifically increased the acetylation of ACADL and CPT1a, which was associated with reduced lipid metabolism. Dietary glucose supplementation did not induce these mitochondrial impairments.
Why it matters
This work identifies specific post-translational and structural mechanisms by which dietary fructose uniquely worsens high-fat-diet-induced hepatic mitochondrial dysfunction and impairs fat oxidation compared to glucose.
Limits
The findings are derived solely from a mouse model, and relevance to human metabolic regulation remains to be established. The abstract does not report sample sizes, specific sugar doses, duration of feeding, or numerical effect sizes with confidence intervals.
Cited by
- supports Fructose promotes liver fat accumulation while simultaneously blocking hepatic fat oxidation.