Polyphenols and non-alcoholic fatty liver disease: impact and mechanisms

• Published in: Proceedings of the Nutrition Society Vol. 75; no. 1; pp. 47 - 60
• Main Authors: Rodriguez-Ramiro, I., Vauzour, D., Minihane, A. M.
• Format: Journal Article
• Language: English
• Published: Cambridge, UK Cambridge University Press 01.02.2016
• Subjects: Adipose tissue; AMP-activated protein kinase; anti-inflammatory activity; Antioxidants; beta oxidation; Bioactive compounds; cell culture; clinical trials; Cocoa; Conference on ‘Diet, gene regulation and metabolic disease’; fatty acids; fatty liver; Flavonoids; Fruits; humans; Hypertension; Insulin resistance; lipogenesis; liver; Liver cancer; Liver cirrhosis; Liver diseases; mechanism of action; metabolic diseases; Metabolic disorders; metabolic syndrome; Metabolites; obesity; Oxidation; Oxidative stress; Pathophysiology; phenotype; Polyphenols; risk reduction; Rodents; Symposium 2: Micronutrients, phytochemicals, gene expression and metabolic disease; therapeutics; Obesity; Insulin resistance; Flavonoids; PPARα; Sterol regulatory element-binding protein 1c; Steatosis; FA fatty acids; MCD methionine and choline deficiency; NASH non-alcoholic steatohepatitis; SIRT-1 sirtuin 1; CPT carnitine palmitoyl transferase 1; HSE Hibiscus sabdariffa L. extract; SREBP-1c sterol regulatory element-binding protein 1c; JNK c-Jun N-terminal kinase; NAFLD non-alcoholic fatty liver disease; Nrf2 nuclear factor-erythroid 2-related factor 2; HFD high fat diet; AMPK AMP-activated protein kinase
• DOI: 10.1017/S0029665115004218
• ISSN: 0029-6651; 1475-2719

Non-alcoholic fatty liver disease (NAFLD) is considered to be the hepatic component of the metabolic syndrome and its prevalence is rapidly increasing due to its strong association with insulin resistance and obesity. At present, given that NAFLD is highly prevalent and therapies are limited, much attention is focused on identifying effective dietary strategies for the prevention and treatment of the disease. Polyphenols are a group of plant bioactive compounds whose regular consumption have been associated with a reduction in the risk of a number of metabolic disorders associated with NAFLD. Here we review the emerging and relatively consistent evidence from cell culture and rodent studies showing that select polyphenols positively modulate a variety of contributors to the NAFLD phenotype, through diverse and complementary mechanisms of action. In particular, the reduction of de novo lipogenesis (via sterol regulatory element-binding protein 1c) and increased fatty acid β-oxidation, presumably involving AMP-activated protein kinase activation, will be discussed. The indirect antioxidant and anti-inflammatory properties of polyphenols which have been reported to contribute to the amelioration of NAFLD will also be addressed. In addition to a direct study of the liver, rodent studies have provided insight into the impact of polyphenols on adipose tissue function and whole body insulin sensitivity, which are likely to in part modulate their impact on NAFLD development. Finally an overview of the limited data from clinical trials will be given along with a discussion of the dose extrapolation from animal studies to human subjects.