Effect of Flavanol-Rich Cacao Extract on the Profile of Mood State in Healthy Middle-Aged Japanese Women: A Randomized, Double-Blind, Placebo-Controlled Pilot Study

To investigate the effects of flavanol-rich cacao extract on healthy middle-aged women’s fatigue and mood conditions, we conducted a randomized, double-blind, placebo-controlled study in women aged 40–60 years who had reported fatigue and had shown high levels of a serum oxidative stress marker. We randomized the participants (n = 60) into equal groups receiving either a beverage containing cacao flavanols (240 mg/200 mL/day) or a placebo for 8 weeks. Before and after the 8-week treatment, we determined the participants’ Chalder fatigue scale (CFS) scores, various mood states, autonomic nervous system (ANS) activity levels, and their ANS balance. The results demonstrated that among the mood states, the indicators of negative mood (e.g., depression, fatigue, and anger) and the total mood disturbance score were significantly lower in the cacao group compared to the placebo group after the treatment (p < 0.05). The change in the index of positive mood (i.e., vigor) from baseline to 8 weeks was significantly higher in the cacao group versus the placebo group (p < 0.05). There were no significant between-group differences in the changes in the CFS score or ANS activity level. The consumption of flavanol-rich cacao extract both suppressed negative moods and promoted positive moods in healthy middle-aged women. These results suggest that cacao flavanols may be a useful food material that can improve variable mood conditions in middle-aged women and support their active lives.