Anti-obesity effect of eucalyptus leaf extract containing oenothein B in healthy Japanese adults: a randomized, placebo-controlled, double-blind, parallel-group study

Abstract

Background: Excessive ingestion of fructose can lead to obesity and related diseases. Eucalyptus leaf extract (ELE) contains oenothein B, which inhibits intestinal fructose absorption.Objective: The antiobesity effects of ELE containing oenothein B were evaluated in healthy Japanese whose body mass index (BMI) was ≥ 23 and < 30 kg/m2.Methods: A randomized, placebo-controlled, double-blind, parallel-group study was performed to evaluate the effect of ELE consumption, for 12 weeks at a 3.38 mg/day dose of oenothein B, on the abdominal visceral fat area (VFA) as the primary outcome. Results were compared to those of a placebo group.Results: Of the 721 individuals who underwent screening, 198 were randomly allocated into two groups. A total of 95 subjects in the placebo group and 94 in the intervention group were established as the per-protocol set. VFA in the intervention group significantly decreased compared to that in the placebo group 12 weeks after initiating intervention. This reduction in VFA was considered to have clinical significance. Among the secondary outcomes, VFA, waist circumference, and muscle mass after 8 weeks, as well as body weight and BMI after 12 weeks, were significantly lower in the intervention group compared to the placebo group.Conclusion: ELE containing oenothein B may be effective against obesity and related diseases by reducing VFA levels. Keywords: human trial; Eucalyptus globulus; oenothein B; polyphenol; hydrolyzable tannin; ellagitannin; dietary fructose consumption; dietary survey; Calorie and Nutrition Diary; glucose transporter 5

An assessment of clinical trials used in functional food science

“…Pharmaceutical companies typically fund a trial to advance knowledge on a new drug when there is a potential opportunity for commercialization and patenting protection. Functional foods do not usually have a significant gain that justifies a large financial investment, nor are there patenting protections in most functional food products [24].…”

“…Large pharmaceutical companies usually have employees fluent in Clinical Trial Applications (CTA) and ethics proposals documents which are not commonly found in the field of functional food [24].…”

“…In pharmaceutical trials, often the placebo is the drug that is being tested without the active ingredient. However, it is harder to find a suitable placebo in functional food clinical trials as food placebos may lack the same texture, taste, and appearance as the food being tested [24][25].…”

“…In pharmaceutical studies, patients will get the tested drug at a physician's office. However, in functional food clinical trials, it is difficult to regularly deliver food to patients [24,[26][27].…”

“…However, this is conditional on patients owning a freezer and therefore may be a challenge for studies involving economically disadvantaged populations. It is also useful to carry out preliminary smaller trials that allow for food to be eaten in a timely manner and ensure that bioactive compounds contribute to the desired biological effect [24].…”