A green-Mediterranean (green-MED) diet rich in plant-based polyphenols reduced liver fat and decreased nonalcoholic fatty liver disease (NAFLD) by half, according to results of a randomized clinical trial published in Gut.
With diet and lifestyle modifications being the cornerstone of NAFLD treatment, researchers sought to examine the effect of a modified Mediterranean diet enriched with plant-based polyphenols and less red and processed meat on reduction of fat accumulation in the liver.
In the current 18-month Dietary Intervention Randomized Controlled Trial Polyphenols Unprocessed (DIRECT PLUS) study (ClinicalTrials.gov Identifier: NCT03020186), participants with abdominal obesity were randomly assigned 1:1:1 to follow a healthy dietary regimen (HDG), traditional Mediterranean (MED), and green-MED diets. All the dietary regimens were combined with physical activity.
Participants from both MED groups received more than 440 mg/day of polyphenols by consuming 28g of walnuts per day. In addition, participants from the green-MED group ingested additional polyphenols, nearly 800mg/day, by consuming green tea (3-4 cups/day) and Mankai (100g/day frozen cubes) green shakes. The primary outcome was the change in liver fat content after 18 months, measured by proton magnetic resonance spectroscopy (H-MRS).
The study included 249 participants with a mean age of 51 years; 88% were men and the mean body mass index (BMI) was 31.3 kg/m2. Baseline characteristics were comparable between the 3 intervention groups. Almost 90% of the participants adhered to the interventions after 18 months, and 78% had eligible follow-up H-MRS scans.
Results of the study reported an overall reduction in liver fat in all the intervention groups. However, participants in the green-MED group had the highest reduction in liver fat (-38.9% proportionally) compared with participants in the MED (-19.6% proportionally) and HDG group (-12.2% proportionally). The results were significant between the 2 MED groups after adjusting for weight loss (P =.035).
NAFLD prevalence dropped from 62% at baseline to 54.8% in the HDG group, 47.9% in the MED group, and 31.5% in the green-MED group (P =.012). Significant reduction in liver fat was independently associated with higher serum folate levels, altered microbiome, increased Mankai and walnuts consumption, and decreased red and processed meat consumption (P <.05 for all).
This trial was limited by the inclusion of primarily men in the study cohort, restricting its generalizability. Additionally, assessment of adherence to study interventions was mainly based on self-reports.
Researchers concluded, “[A] green-MED diet, enriched with specific polyphenols and decreased red and processed meat consumption, amplifies the beneficial effect of the MED diet on hepatic fat reduction, beyond weight loss.”
Disclosure: Some study authors declared affiliations with pharmaceutical and/or supplement companies. Please see the original reference for a full list of disclosures.
Yaskolka Meir A, Rinott E, Tsaban G, et al. Effect of green-Mediterranean diet on intrahepatic fat: the DIRECT PLUS randomised controlled trial. Gut. 2021;70(11):2085-2095. doi:10.1136/gutjnl-2020-323106