Effect of Tomato Consumption on Liver Steatosis in MASLD: A Randomized Controlled Trial (POMOSANO Study)

Background: Metabolic dysfunction-associated steatotic liver disease (MASLD) is a common chronic liver disease for which lifestyle modification remains the main treatment. However, the role of specific dietary components is not fully understood. We investigated whether daily tomato consumption, a source of Mediterranean diet bioactive compounds, improves hepatic steatosis in adults with MASLD. Methods: In the randomized controlled POMOSANO trial, 79 adults with MASLD (BMI ≤ 30 kg/m²) were assigned to a tomato intervention group (n = 42), consuming 200 g/day of raw tomatoes and 50 g/day of tomato sauce, or to a control group (n = 37) following a tomato-free diet. The intervention lasted 6 weeks. Hepatic steatosis was assessed by the FibroScan^® controlled attenuation parameter (CAP). Secondary outcomes included anthropometric measures, body composition, liver stiffness, and metabolic and biochemical markers. Linear mixed-effects models were used to evaluate changes over time. Results: CAP decreased in both groups, with a greater reduction in the intervention group (median change: -35.00 vs. -18.00 dB/m). The adjusted linear mixed-effects model confirmed that the change in CAP in the control group was β = -12.81 (95% CI -25.55 to -0.08; p = 0.0490). Crucially, the treatment-by-time interaction was significant (β = -26.63, 95% CI -44.00 to -9.25; p = 0.0030), demonstrating a significantly greater reduction in hepatic steatosis in the tomato intervention group compared to the control group. CAP values were also significantly lower in the intervention group at follow-up (p = 0.0433). The adjusted linear mixed-effects model confirmed a significant reduction in CAP over time (β = -12.81, 95% CI -25.55 to -0.08; p = 0.0490) and a significant treatment-by-time interaction (β = -26.63, 95% CI -44.00 to -9.25; p = 0.0030), indicating a greater reduction in hepatic steatosis in the intervention group. No significant between-group differences were observed for liver stiffness, FIB-4 index, body weight, body composition, or most metabolic and biochemical markers. Conclusions: Daily consumption of raw tomatoes and tomato sauce reduced hepatic steatosis in adults with MASLD, supporting tomato-rich dietary strategies as a potential nutritional approach for MASLD management.