Effects of Turkish Coffee and Green Tea in Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD), recently included under the broader term metabolic dysfunction-associated steatotic liver disease (MASLD), is the most common chronic liver disease worldwide and is strongly associated with obesity, insulin resistance, and metabolic abnormalities. Lifestyle modification, particularly dietary interventions, is considered the cornerstone of NAFLD management.

This randomized controlled study was designed to investigate the effects of Turkish coffee and green tea consumption combined with a Mediterranean diet intervention on liver steatosis, biochemical parameters, and anthropometric measurements in individuals diagnosed with fatty liver disease.

Participants were assigned to three groups: a Turkish coffee group, a green tea group, and a control group. All participants received a 12-week Mediterranean diet intervention. In addition to the dietary intervention, the Turkish coffee group consumed Turkish coffee twice daily, while the green tea group consumed green tea three times daily. The control group continued with the Mediterranean diet without additional beverage intervention.

Before and after the 12-week intervention, participants were evaluated for liver steatosis using ultrasonography, liver function tests (including alanine aminotransferase [ALT], aspartate aminotransferase [AST], and gamma-glutamyl transferase [GGT]), metabolic parameters, and anthropometric measurements.

The aim of this study is to determine whether Turkish coffee and green tea consumption as an adjunct to a Mediterranean diet may have beneficial effects on liver fat accumulation and metabolic health parameters in individuals with fatty liver disease.

Inclusion criteria

• Participants aged 19-65 years with a diagnosis of non-alcoholic fatty liver disease (NAFLD).
• Not using medications for diabetes, dyslipidemia, or rheumatoid arthritis.
• Not using dietary supplements.
• No dietary program followed within the previous month.
• No severe psychiatric disorders.
• Willingness to participate in the study and provide informed consent.

Exclusion criteria

• Presence of diabetes, dyslipidemia, or rheumatoid arthritis.
• Alcohol consumption.
• Positive hepatitis B surface antigen (HBsAg), hepatitis C positivity, autoimmune hepatitis, liver cirrhosis, toxic hepatitis, or alanine aminotransferase (ALT) levels ≥10 times the upper limit of normal.
• Presence of liver malignancy or hepatic decompensation.
• Use of systemic corticosteroids or methotrexate within the previous 6 months.
• Pregnancy or lactation.
• Regular use of dietary supplements.
• Following a dietary program within the previous month.
• Presence of severe psychiatric disorders.
• High daily consumption of tea and coffee.