Aim: Excessive fructose ingestion causes fat accumulation and can lead to fatty liver, obesity, and related diseases. Eucalyptus leaf extract (ELE) contains oenothein B, which inhibits fructose absorption in the intestine. In this study, we evaluated the effects of ELE on fat accumulation caused by sugar-sweetened beverage intake in adult Japanese men with a body mass index of ≥ 23 and < 30 kg/m2.
Methods: In this randomized, placebo-controlled, double-blind, and parallel-group pilot study, participants consumed test capsules containing oenothein B (3.38 mg/day), along with a beverage containing free sugars (22.5 g/day), as a loading diet for 12 weeks. The abdominal visceral fat area (VFA) and controlled attenuation parameter (CAP), which is an indicator of hepatic fat levels, were measured and compared to those in the placebo group.
Results: Twenty participants were included in the analysis of the placebo and intervention groups. After 12 weeks, VFA and CAP increased significantly from baseline (p = 9.81 × 10-3 and 1.59 × 10-2) in the placebo group, whereas no significant increase was observed in the intervention group. Sensitivity analysis after unblinding revealed that the CAP was significantly lower in the intervention group (p = 4.84 × 10-2) than that in the placebo group after 12 weeks.
Conclusion: ELE ingestion suppressed visceral and hepatic fat accumulation. Thus, oenothein B-containing ELE may be a useful antiobesity agent. This is the first report showing that the consecutive ingestion of dietary free sugars results in hepatic and visceral fat accumulation in adult Japanese men.
Trial registration: UMIN000037428; https://center6.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno=R000042668.
Keywords: Eucalyptus globulus; anti‐obesity; dietary fructose consumption; human trial; liver steatosis; polyphenol.
© 2025 Japan Society of Hepatology.