Ad libitum Mediterranean or low fat diets as treatments for non-alcoholic fatty liver disease?

Targher, Giovanni and Byrne, Christopher (2018) Ad libitum Mediterranean or low fat diets as treatments for non-alcoholic fatty liver disease? Hepatology, 68 (5), 1668-1671. (doi:10.1002/hep.30142).

Record type: Editorial

Abstract

The 2016 European Society of Cardiology guidelines recommended a total fat intake of ≤30% of which ≤10% should consist of saturated fats to reduce risk of cardiovascular disease (CVD) (1). These guidelines also suggested decreasing saturated fat intake by substitution with polyunsaturated fatty acids (1). In June 2017, the American Heart Association's presidential advisory on dietary fats stated that replacing saturated fat with polyunsaturated vegetable oil reduces the incidence of CVD by ~30% (2). Importantly, this shift from saturated to unsaturated fats occurs when a Westernised diet containing processed foods is replaced by the Mediterranean diet (MD) (2). Traditionally, the MD contains an abundance of plant foods, including legumes, vegetables, fruits, nuts, grains and fish (3). Several observational cohort studies and some randomized clinical trials (RCT) have suggested that MD reduces the incidence of CVD (3).

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HEP Editorial_Diet and NAFLD_accepted - Accepted Manuscript

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Accepted/In Press date: 13 June 2018

e-pub ahead of print date: 2 August 2018

Published date: November 2018

Additional Information: Although diet induced weight loss is first‐line treatment for patients with non‐alcoholic fatty liver disease (NAFLD), long‐term maintenance is difficult. The optimal diet for either improvement in NAFLD or associated cardio‐metabolic risk factors regardless of weight loss, is unknown. We examined the effect of two ad libitum isocaloric diets [Mediterranean (MD) or Low Fat (LF)] on hepatic steatosis and cardio‐metabolic risk factors. Subjects with NAFLD were randomized to a 12‐week blinded dietary intervention (MD vs LF). Hepatic steatosis was determined via magnetic resonance spectroscopy (MRS). From a total of 56 subjects enrolled, 49 subjects completed the intervention and 48 were included for analysis. During the intervention, subjects on the MD had significantly higher total and monounsaturated fat but lower carbohydrate and sodium intakes compared to LF subjects (p<0.01). At week 12, hepatic steatosis had reduced significantly in both groups (p<0.01) and there was no difference in liver fat reduction between the groups (p=0.32), with mean (SD) relative reductions of 25.0% (±25.3%) in LF and 32.4% (±25.5%) in MD. Liver enzymes also improved significantly in both groups. Weight loss was minimal and not different between groups [‐1.6 (±2.1)kg in LF vs −2.1 (±2.5)kg in MD, (p=0.52)]. Within‐group improvements in the Framingham risk score, total cholesterol, serum triglyceride, and HbA1c were observed in the MD (all p<0.05) but not with the LF diet. Adherence was higher for the MD compared to LF (88% vs. 64%, p=0.048). Conclusions: Ad libitum low fat and Mediterranean diets both improve hepatic steatosis to a similar degree.