Taking daily exercise and following a Mediterranean diet for 6 months, either with or without antioxidant supplementation, led to significant reductions in accumulated liver fat, reduced liver stiffness (a marker of fibrosis) and blood lipids, together with improvements in anthropometric measurements.
Compared with patients following the dietary intervention alone, intake of an antioxidant formula additionally led to a significant improvement in insulin sensitivity measures, reported the research team from Magna Graecia University, Catanzaro.
“Our study confirms that the Mediterranean diet can improve anthropometric parameters and lipid profile and can contribute to reducing hepatic fat accumulation and liver stiffness,” wrote first author Professor Ludovico Abenavoli.
“Moreover, the association of this dietetic regimen with antioxidant supplementation can contribute to improving the insulin sensitivity parameters,” he continued.
The benefits of a Mediterranean diet on cholesterol and blood pressure are widely recognised. However, these findings are significant as intervention studies on the effectiveness of the Mediterranean diet on NAFLD are, to date, limited.
The study is unique in its identification of additional metabolic health benefits of consuming antioxidants in conjunction with diet and lifestyle modifications.
“We found that overweight patients compliant to a Mediterranean diet that increase their physical activity in association with these antioxidants, also show an improvement in blood level [measures] of glucidic and lipidic metabolism,” commented Abenavoli.
A group of 50 overweight men with NAFLD were randomised into three groups. Groups A and B followed a mildly hypocaloric Mediterranean diet (1400-1600 kilocalories/day) for six months and were recommended to take daily exercise.
Group B received an antioxidant formula, Bilirel (BIL), manufactured by Pharmaluce, San Marino. The daily dosage consisted of silymarin 240 milligrams (mg), chlorogenic acid 15 mg, protopine 0.08 mg, l-methionine 300 mg and l-glutathione 20 mg.
(This over-the-counter supplement is freely available in Italy. The researchers have no commercial connection or conflict of interest with the manufacturers).
Group C (control) were monitored over the 6-month period without prescribed treatment other than being given the instruction ‘to lose weight’.
Compared with controls, both the diet-only and the diet-plus-antioxidants groups showed significant improvements in FL index, liver stiffness (measured by ‘Fibroscan’ transient elastography), insulin resistance parameters, blood lipids (triglycerides and ‘bad’ cholesterol) and anthropometric measures.
It was in the area of insulin resistance parameters that supplement group subjects showed significant additional benefits versus the diet-only group. Homeostatic model assessment insulin resistance (HOMA-IR) was 43% lower in Group B, compared with 6% higher in group A. Insulin and fasting glucose end-points were also significantly lower in Group B patients.
The researchers attributed the improved glucose metabolism on two particular constituents of the antioxidant formula.
“The metabolic changes observed in our study can be explained by the synergic action of the Mediterranean diet in association with chlorogenic acid and silymarin,” they suggested.
Abenavoli is keen to investigate the possible benefits of probiotics on NAFLD when combined with the Mediterranean diet.
“My idea is to study the effect of probiotics in particular [species of] Lactobacillus, on the evolution and progression of NAFLD, in particular in association with the Mediterranean diet,” he said.
“My hope is that the role played by probiotics and the Mediterranean diet, rich in antioxidants, but also rich in fibre, can influence liver fat accumulation and improve intestinal permeability.”
Previous research has established a link between elevated gut permeability and NAFLD.
Mediterranean diet for metabolic health
Abenavoli suggested that people should switch away from the Western diet andconsider adopting a Mediterranean diet to help restore metabolic equilibrium. He also suggested that the relative cost of fresh vegetables versus junk food was a factor limiting adoption of a Mediterranean style diet in the UK, compared with Italy.
“But in general it is necessary to change diet to one rich in fibre, vegetables, omega-3, all the characteristics of a Mediterranean diet. This can help the metabolism, in particular in overweight patients,” recommended Abenavoli.
The way forward?
Abenavoli said that research is unequivocal in prescribing lifestyle change as the first step in treating NAFLD. However, he suggested that much less agreement exists on the relative efficacy of individual drugs used for NAFLD therapy.
He explained that consequently “We are in a moment when it is important to define the exact pathogenesis of liver disease and to find a solution.
“The application of a diet rich in antioxidants and with other antioxidant supplementation can help to stop the progression of this disease,” he concluded.
Volume 9, issue 8. Published online, doi: 10.3390/nu9080870
“Effect of Mediterranean Diet and Antioxidant Formulation in Non-Alcoholic Fatty Liver Disease: A Randomized Study”
Authors: Ludovico Abenavoli, Marta Greco et al