Big effect
Red grape flavonoids significantly lowered a liver enzyme in NAFLD patients — but didn't touch inflammation or scarring
This meta-analysis of 689 people with fatty liver disease found a moderate, consistent drop in AST (a marker of liver stress), but the benefit stopped there — inflammatory markers and fibrosis scores didn't budge, and the evidence rests on only four studies, so the picture is promising but far from settled.
AST is an enzyme that leaks into the blood when liver cells are damaged; a lower level suggests less ongoing liver injury. In this analysis, flavonoid supplements (from red grapes and other sources) reduced AST in people with non-alcoholic fatty liver disease, but had no effect on inflammation or liver scarring — meaning the improvement was limited to one aspect of liver health. The findings come from a systematic review of clinical trials, but the dose used wasn't specified, and the results may not apply to people without fatty liver disease.
Where this fits in the evidence
Pillser has synthesized 4 studies on Red Grape for Reduced Aspartate Aminotransferase Level — overall evidence strength: Moderate.
Across 4 studies, 3 reported beneficial effects of red grape-derived interventions (primarily grape seed extract) on reducing aspartate aminotransferase (AST) levels, with effect sizes ranging from small to moderate. Effects were observed in clinical populations with NAFLD and β-thalassemia at doses of 100 mg/day and 520 mg/day over 4–8 weeks. The evidence is moderate, with 3 statistically significant findings, but the small number of studies and narrow populations limit generalizability.
The study
- Systematic Review
- n = 689
- 2025-09-15
- Frontiers in nutrition
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