TITLE:
Evaluation of the Effects of Food Containing Epilobium angustifolium Extract on Quality of Life Related to Nocturia Urination Using the N-QOL Questionnaire: A Randomized, Double-Blind, Placebo-Controlled, Parallel-Group Study
AUTHORS:
Naohiro Osada, Yuki Hirashima, Sakura Mashiki, Kohei Fujiki, Saeko Isaka, Nobutaka Kusaba, Takatoshi Ogami, Tomoyasu Kamiya, Kinya Takagaki, Yukinao Ishibashi
KEYWORDS:
Epilobium angustifolium Extract, Nocturia, N-QOL Questionnaire
JOURNAL NAME:
Food and Nutrition Sciences,
Vol.16 No.10,
October
28,
2025
ABSTRACT: Background: Nocturia, characterized by waking during the night to urinate, is a common condition that significantly impacts quality of life (QOL) by disrupting sleep and reducing daytime vitality. Epilobium angustifolium, a medicinal plant, has shown potential in improving nocturia-related symptoms due to its active constituent, oenothein B, which possesses anti-inflammatory and antioxidant properties. This study aimed to evaluate the effects of Epilobium angustifolium extract on nocturia-related QOL using the Nocturia Quality of Life Questionnaire (N-QOL). Methods: We conducted a 9-week, randomized, double-blind, placebo-controlled, parallel-group trial involving healthy adults with frequent urination and self-perceived sleep disturbances. The participants were randomly assigned to receive either tablet containing Epilobium angustifolium extract providing 15 mg/day of oenothein B or a placebo for 8 weeks. The primary outcome was the N-QOL score, assessed at baseline, and at 4 and 8 weeks. Results: A total of 47 participants completed the study and were included in the analysis. The active group showed significantly greater improvements in the N-QOL total score and Sleep/Energy score compared to the placebo group at both 4 and 8 weeks. No significant differences were observed to the Bother/Concern score or Overall Health Perception. No adverse events related to the study food were reported. Conclusions: The intake of Epilobium angustifolium extract providing 15 mg/day of oenothein B significantly improved the nocturia-related QOL, particularly in the domains of sleep and energy, in adults with frequent urination tendencies and sleep complaints. These findings suggest that Epilobium angustifolium extract may serve as a practical and safe approach to managing nocturia-related QOL.