Effect of long-term intake of α-lactalbumin on menstruation-related symptoms and quality of life in healthy Japanese women: a randomized, double-blind, placebo-controlled study.

BACKGROUND/OBJECTIVES: Coping strategies for menstruation-related symptoms are required to support women's health-related quality of life (QoL) and the continued social advancement of women. Previous studies have reported that short-term intake of α-lactalbumin (aLA) alleviates physical symptoms during menstruation. In this study, we investigated the effects of long-term intake of aLA on menstruation-related symptoms and QoL in healthy Japanese women. METHODS: A randomized, double-blind, placebo-controlled study was conducted. Participants were 140 healthy women aged 20-39 years and were randomly assigned to receive aLA (900 mg/day) or placebo for three menstrual cycles. Premenstrual and intramenstrual symptoms were assessed at each cycle. The primary outcome was subjective symptoms on the Menstrual Distress Questionnaire (MDQ), and secondary outcomes were the 36-Item Short Form Health Survey (SF-36), subjective symptoms on the Visual Analog Scale, and urinary prostaglandins. RESULTS: The primary outcome, the MDQ, showed no significant differences in the total score or the six factor scores between groups, either premenstrually or during menstruation. In exploratory analyses, aLA intake significantly alleviated the premenstrual MDQ sub-scores "Weight gain" and "Lowered motor coordination" compared with placebo (p < 0.05 for each). Among the secondary outcomes, aLA intake significantly improved the premenstrual role-related and social QoL scores on the SF-36 compared with placebo (p < 0.05). No significant group differences were observed for other items. CONCLUSION: In this trial, long-term aLA supplementation did not improve overall menstruation-related symptoms as assessed by the primary outcome. However, secondary outcomes indicated potential benefits in role-related and social aspects of premenstrual QoL. These findings are exploratory, requiring further studies for confirmation. CLINICAL TRIAL REGISTRATION: https://center6.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000063507, UMIN-CTR UMIN000055576.