Effect of soy lecithin on fatigue and menopausal symptoms in middle-aged women: a randomized, double-blind, placebo-controlled study

BACKGROUND: Lecithin is a complex mixture of phospholipids which compose lipid bilayer cell membranes. Lipid replacement therapy, or administration of phospholipids for the purpose of repairing the dmaged cell membranes, had been shown to alleviate fatigue. The present study aimed to investigate the effect of soy lecithin on fatigue in middle-aged women, as well as other menopausal symptoms and various health parameters. METHODS: This randomized, double-blind, placebo-controlled study included 96 women aged 40 to 60 years who complained of fatigue. The participants were randomized to receive active tablets containing high-dose (1200 mg/day; n = 32) or low-dose (600 mg/day; n = 32) soy lecithin, or placebo (n = 32), for 8 weeks. The following parameters were evaluated: age, menopausal status, lifestyle factors, physical and psychological symptoms of menopause, subjective symptoms of insomnia and fatigue, body composition, cardiovascular parameters, and physical activities and objective sleep states obtained from actigraphy before and 4 and 8 weeks after treatment. Fatigue was evaluated using the Profile of Mood States (POMS)-brief, Menopausal Health-Related Quality of Life questionnaire, Chalder Fatigue Scale, and Brief Fatigue Inventory. RESULTS: Eighty-nine women completed the study. There were no significant differences in the changes in Chalder Fatigue Scale score (placebo vs low-dose vs high-dose groups: −2.9 ± 1.1, −3.2 ± 1.1, and −3.5 ± 1.0; P = 0.79). On the other hand, the improvements were greater in the high-dose group compared with the placebo group concerning vigor scores in the POMS-brief (1.9 ± 0.7 vs 0.2 ± 0.6; P = 0.02), diastolic blood pressure (−4.1 ± 1.8 vs 1.2 ± 1.9; P = 0.05), and cardio-ankle vascular index (−0.4 ± 0.2 vs 0.07 ± 0.1; P = 0.03) after 8 weeks of treatment. CONCLUSIONS: High-dose (1200 mg/day) soy lecithin not only increases vigor, but also lowers the diastolic blood pressure and cardio-ankle vascular index in middle-aged women who present with fatigue. TRIAL REGISTRATION: UMIN-CTR UMIN000017127.