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Background The equilibrium of the scalp microbiome is important for maintaining healthy scalp conditions, including sebum secretion, dandruff, and hair growth. Many different strategies to improve scalp health have been reported; however, the effect of postbiotics, such as heat-killed probiotics, on scalp health remains unclear. We examined the beneficial effects of heat-killed probiotics consisting of Lacticaseibacillus paracasei, GMNL-653, on scalp health. Results Heat-killed GMNL-653 could co-aggregate with scalp commensal fungi, Malassezia furfur, in vitro, and the GMNL-653-derived lipoteichoic acid inhibited the biofilm formation of M. furfur on Hs68 fibroblast cells. The mRNA of hair follicle growth factors, including insulin-like growth factor-1 receptor (IGF-1R), vascular endothelial growth factor, IGF-1, and keratinocyte growth factor was up-regulated in skin-related human cell lines Hs68 and HaCaT after treatment with heat-killed GMNL-653. For clinical observations, we recruited 22 volunteer participants to use the shampoo containing the heat-killed GMNL-653 for 5 months and subsequently measured their scalp conditions, including sebum secretion, dandruff formation, and hair growth. We applied polymerase chain reaction (PCR) to detect the scalp microbiota of M. restricta, M. globosa, Cutibacterium acnes, and Staphylococcus epidermidis. A decrease in dandruff and oil secretion and an increase in hair growth in the human scalp were observed after the use of heat-killed GMNL-653-containing shampoo. The increased abundance of M. globosa and the decreased abundance of M. restricta and C. acnes were also observed. We further found that accumulated L. paracasei abundance was positively correlated with M. globosa abundance and negatively correlated with C. acnes abundance. S. epidermidis and C. acnes abundance was negatively correlated with M. globosa abundance and positively correlated with M. restricta. Meanwhile, M. globosa and M. restricta abundances were negatively associated with each other. C. acnes and S. epidermidis abundances were statistically positively correlated with sebum secretion and dandruff, respectively, in our shampoo clinical trial. Conclusion Our study provides a new strategy for human scalp health care using the heat-killed probiotics GMNL-653-containing shampoo. The mechanism may be correlated with the microbiota shift.

Background The Binge Eating Scale (BES) is a widely used measuring tool to assess binge eating problems in Western countries. However, the psychometric properties of such scales among cross-cultural youth groups are insufficient, and the factor structure continues to be debated; therefore, further research is needed. The aim of this study was to examine the properties of BES among overweight college students in Taiwan. Methods A cross-sectional design and convenience sampling were adopted to recruit 300 overweight students from five universities. A translated Traditional Chinese version of BES was used for the survey, and the validity of the scale was tested using the Confirmatory Factor Analysis (CFA) and Bulimic Investigatory Test, Edinburgh (BITE). The reliability was evaluated using internal consistency and test–retest reliability. Results The CFA results showed a reasonable model fit. The first-order two-factor model was consistent with that of the original BES and significantly correlated with the criterion of BITE score. Cronbach’s α value, representing internal consistency reliability, and the intraclass correlation coefficient of repeated measures made one month apart were both 0.83, indicating good reliability and stability. Significant correlations were observed between the BES score and sex and BMI; however, no correlation was observed between BES scores and age. Conclusion The BES presents sound psychometric properties, has good cross-cultural applicability, and can be used as a first-line screening tool by mental health professionals to identify the severity of binge eating behavior among overweight college students in Taiwan. It is recommended that participant diversity and obesity indicators be incorporated into the scale in the future to establish a universal psychometric tool.