Mediterranean Diet Remains Effective Treatment for Nonalcoholic Fatty Liver Disease

Results from a systematic review and meta-analysis published in Clinical Nutrition support current guidelines recommending a Mediterranean dietary intervention for nonalcoholic fatty liver disease (NAFLD) management.

Researchers from Newcastle University in the United Kingdom searched publication databases through October 2021 for studies about dietary interventions in the setting of NAFLD. A total of 26 trials totaling 3037 participants were included in the analysis.

The studies were conducted in lower-middle income (n=5), upper-middle income (n=5), and high-income (n=16) countries and were of randomized (88.5%) or clinical (11.5%) controlled designs.

The study population included 54.7% men; study participants had a mean age of 48.3±5.9 years; and BMI was 31.0±2.3 kg/m². Patients had NAFLD (n=21), nonalcoholic steatohepatitis (n=2), abdominal obesity or dyslipidemia (n=2), or were at risk for type 2 diabetes (n=1).

The interventions analyzed across the 26 trials included the Mediterranean diet (n=13; 50%), calorie restriction (n=9; 35%), and Mediterranean diet components (n=4; 15%).

Compared with standard care, Mediterranean dietary interventions improved alanine aminotransferase (ALT), aspartate aminotransferase (AST), total cholesterol, triglycerides, Fatty Liver Index (FLI), hepatic steatosis (HS), liver stiffness measures (LSM), fasting insulin, Homeostatic Model Assessment of Insulin Resistance (HOMA-IR), waist circumference, and body weight loss. Individuals on a Mediterranean diet consumed more fiber, fruit, and nuts and fewer calories, carbohydrates, and sodium.

For the calorie restriction interventions, ALT, AST, low-density lipoprotein cholesterol, triglycerides, FLI, HS, LSM, histological NAFLD Activity Score, fasting insulin, HOMA-IR, waist circumference, and body weight were improved. During calorie restriction, participants consumed more protein and fiber compared with standard care.

In the meta-analysis, the Mediterranean diet improved ALT (mean difference [MD], -6.54; 95% CI, -12.02 to -1.05; P =.02; I²=81%), FLI (MD, -15.60; 95% CI, -22.01 to -9.18; P <.00001; I²=71%), and LSM (MD, -0.75; 95% CI, -1.51 to 0.00; P =.05; I²=87%); calorie restriction improved ALT (MD, -5.44; 95% CI, -8.01 to -2.88; P <.0001; I²=67%), FLI (MD, -7.34; 95% CI, -13.11 to -1.57; P =.01), HS (MD, -0.72; 95% CI, -0.97 to -0.46; P <.00001; I²=0%), and LSM (MD, -0.39; 95% CI, -0.69 to -0.10; P =.009; I²=0%).

The analysis may have been biased by the differing interventions and comparator conditions.

“The current evidence suggests that most dietary interventions investigated in these trials were acceptable, and their adoption was associated with positive clinical outcomes,” the study authors wrote.

Reference

Haigh L, Kirk C, El Gendy K, et al. The effectiveness and acceptability of Mediterranean diet and calorie restriction in non-alcoholic fatty liver disease (NAFLD): A systematic review and meta-analysis. Clin Nutr. Published online July 1, 2022. doi:10.1016/j.clnu.2022.06.037