The aim of the present study was to clarify the influence of inulin and lactulose-fortified prebiotic food intakes on bone metabolism turnover among Japanese female athletes. The participants included 29 female athletes aged 18–25 years. They were requested to consume their habitual foods or drinks with one pack of prebiotic food every day for 12 weeks. Dietary intake, training time, body composition, blood sample, and fecal microbiota were assessed during this intervention period. Body composition, total energy intake, and training time of the participants revealed no significant changes during the intervention period. The occupation ratio of Bifidobacterium spp. was significantly increased at 3 and 4 weeks (18.0 ± 8.3% and 17.6 ± 8.5%, respectively) compared to that of pre-intervention (11.7 ± 7.3%) (p = 0.019 and p = 0.035, respectively). The serum TRACP-5b level was significantly decreased at 12 weeks (363 ± 112 mU/dL) compared to that at baseline (430 ± 154 mU/dL) (p = 0.018). These results suggest that the prebiotic food used in this study might have beneficial effects on bone health and gut microbial environment among female athletes. Further studies are warranted to identify the mechanism of the prebiotics–gut–bone axis.

The Japanese government declared a state of emergency from 7 April to 25 May to limit people’s movement due to the coronavirus disease (COVID-19) pandemic. This pandemic negatively affects athletes’ body composition due to inactivity. Therefore, we compared the body composition data (i.e., fat-free mass (FFM) and fat mass (FM)), of 43 Japanese elite fencers (22 men, 21 women), in September 2019 for baseline, and of 21 (12 men, 9 women) who completed the following measurements in June 2020 (POST; immediately after rescinding the emergency state) and September 2020 (POST-4M; 4-months after rescinding the emergency state). Results at baseline indicate no significant differences in body compositions among fencing disciplines. We also confirmed no significant changes in body mass during the 1-year investigation period in either sex. There were no time-course changes in men’s FFM and FM; however, time-course changes in women’s FM were observed. Compared to the baseline, FM values were significantly higher at POST and then returned to baseline levels at POST-4M in women. In conclusion, the 2-month stay-at-home period due to COVID-19 negatively affected women’s FM changes, but not their FFM or men’s FM.

Anxious-depressive attack (ADA) is a recently proposed symptom cluster consisting of sudden intense feelings of distressing emotions with no direct psychological cause. It is characterized by intrusive rumination of mainly regretful memories accompanied by a violent emotional storm, resulting in countermeasures including acting out behaviors. ADA seems to manifest in various anxiety and affective disorders as well as some personality disorders, but may have been overlooked. A previous study showed that patients with ADA were more socially anxious and more depressive than those without ADA, regardless of their diagnoses. Social anxiety disorder (SAD) is one of such disorders with a high prevalence of ADA (44.4%). According to clinical reports, patients with SAD appear hypersensitive to rejection or criticism. The present study examined the relationships among ADA, social anxiety, depression and rejection sensitivity (RS) in patients diagnosed with SAD using structural equation modeling (SEM). Findings showed that RS directly significantly affects ADA, as well as indirectly via depression and social anxiety. Depression had a direct, positive effect on ADA, whereas social anxiety had an indirect effect on ADA via depression. The present study suggests that RS may contribute to the development of ADA in patients with SAD.