Endocrine Abstracts

Men have a higher prevalence and risk of non-alcoholic fatty liver disease (NAFLD) than age-matched women and this may, in part, be related to differences in fatty acid oxidation. Fasting and postprandial fatty acid oxidation was investigated in 11 healthy men and 11 healthy women matched for age (46±2 years vs 46±2 years (mean±S.E.M.)), BMI (28.0±1 vs 27.0±1 kg/m²) and liver fat content (3.4±0.9 vs 3.9±0.7%) measured using magnetic resonance spectroscopy (MRI). Plasma acetoacetate and 3-hydroxybutyrate (3OHB) concentrations were measured as markers of hepatic fatty acid oxidation. Postprandial fatty acid oxidation was investigated by feeding a mixed test meal labelled with a stable-isotope tracer (U13Cpalmitate) and measuring incorporation into expired CO₂ (as a marker of whole body oxidation) and 3OHB (as a marker of hepatic fatty acid oxidation). Men and women had a similar amount of liver fat content despite men having a significantly greater amount of visceral fat (P<0.05). However, overall visceral fat content was related to liver fat content (rs=0.57, P<0.05). Men had higher plasma triglyceride (TG) concentrations than women in the fasting and postprandial state (P<0.05). Although there was no difference in fasting plasma acetoacetate and 3OHB concentrations there was a divergence between men and women with consumption of the test meal with males having notably lower (P<0.05) postprandial concentrations. In contrast, women had a greater appearance of plasma 13C-3OHB and breath 13CO2 than men, indicating that recently ingested dietary fatty acids were entering oxidation pathways to a greater extent in women. These results show differences in dietary fatty acid oxidation between genders where women tend to favour oxidation pathways which may, in part, explain the lower prevalence of NAFLD noted in women.