Intracellular triglyceride deposition in hepatocytes is promoted by bodily adipose tissue dysfunction and insulin resistance. When intrahepatic fat proportion is above 5% in the absence of alcohol consumption, it is called non-alcoholic fatty liver disease (NAFLD). Intrahepatic fat accumulation leads to poor health outcomes and is associated with elevated liver enzymes, insulin resistance, type 2 diabetes, cardiovascular risk and extrahepatic malignancies. The gut microbiome was suggested to have a pivotal role in NAFLD pathogenesis through dysbiosis related changes in hepatic carbohydrate and lipid metabolism.
NAFLD is an increasing global health problem, now already affecting about a quarter of the world population as it can lead to the development of steatohepatitis, liver-cirrhosis and hepatocellular carcinoma. The main treatment for NAFLD is increasing exercise and reducing body weight. No specific dietary recommendations are being made, although strong evidence points towards benefit of a Mediterranean diet, as it has been associated with reduced prevalence of NAFLD, improves cardiometabolic and cardiovascular biomarkers, and reduces all-cause mortality.
The objective of this study was therefore to evaluate the effectiveness of a so-called green-Mediterranean diet, restricted in red/processed meat, and enriched with green plants and polyphenols, on non-alcoholic fatty liver disease. The primary end point of the study was intrahepatic fat loss.
294 subjects with abdominal obesity (mean body mass index=31.3 kg/m2) and/or dyslipidaemia were included and randomized into a regime of healthy dietary guidelines, standard Mediterranean diet and green Mediterranean diet, all accompanied by physical activity. The subjects assigned to the green Mediterranean diet consumed 3-4 cups green tea per day, Mankai aquatic plant strain and green shake in addition to the standard Mediterranean diet. Changes after 18 months were quantified by proton magnetic resonance spectroscopy.
The results show that all approaches resulted in a reduced NAFLD prevalence, but the lowest NAFLD prevalence was seen in subjects using the green Mediterranean diet, followed by the regular Mediterranean diet and the regular diet (31.5% vs 47.9% vs 54.8%). After 18 months, both Mediterranean diet groups had significantly higher total plasma polyphenol levels versus regular diet. Greater IHF% loss was independently associated with increased Mankai and walnuts intake, decreased red/processed meat consumption, improved serum folate and adipokines/lipids biomarkers, changes in microbiome composition (beta-diversity) and specific bacteria (p
These data suggest that a Mediterranean diet, and the green Mediterranean diet in particular is much more effective than other healthy nutritional strategies and strongly reduce NAFLD.
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