Dietary cocoa ameliorates non-alcoholic fatty liver disease and increases markers of antioxidant response and mitochondrial biogenesis in high fat-fed mice

Cocoa powder, derived Theobroma cacao, is a popular food ingredient that is commonly consumed in chocolate. Epidemiological and human intervention studies have reported that chocolate consumption is associated with reduced risk of cardiometabolic diseases. Laboratory studies have reported the dietary supplementation with cocoa or cocoa polyphenols can improve obesity and obesity-related comorbidities in preclinical models. Non-alcoholic fatty liver disease (NAFLD), one such comorbidity, is a risk factor for cirrhosis and hepatocellular carcinoma. Limited studies have examined the effect of cocoa/chocolate on NAFLD and underlying hepatoprotective mechanisms. Here, we examined the hepatoprotective effects of dietary supplementation with 80 mg/g cocoa powder for 10 wks in high fat (HF)-fed obese male C57BL/6J mice. We found that cocoa-supplemented mice had lower rate of body weight gain (22%), hepatic triacylglycerols (28%), lipid peroxides (57%), and mitochondrial DNA damage (75%) than HF-fed controls. These changes were associated with higher hepatic superoxide dismutase and glutathione peroxidase enzyme activity and increased expression of markers of hepatic mitochondrial biogenesis. We also found that the hepatic protein expression of sirtuin 3 (SIRT3), and mRNA expression of peroxisome proliferator activated receptor g coactivator (PGC) 1a, nuclear respiratory factor 1, and forkhead box O3 were higher in cocoa-treated mice compared to HF-fed controls. These factors play a role in coordinating mitochondrial biogenesis and expression of mitochondrial antioxidant response factors. Our results indicate that cocoa supplementation can mitigate the severity of NAFLD in obese mice and that these effects are related to SIRT3/PGC1a-mediated increases in antioxidant response and mitochondrial biogenesis.