In a previous study, we found that proteins from cacao beans (cacao proteins) were resistant to digestive enzymes and that ingestion of the indigestible cacao proteins promoted defecation and altered the intestinal microbiota in mice. Therefore, we investigated whether ingestion of dark chocolate containing high amounts of cacao proteins improves constipation and alters the intestinal microbiota in Japanese women. Bowel movement frequency and stool amount after dark chocolate ingestion were significantly higher than before dark chocolate ingestion and significantly higher than after ingestion of white chocolate with no cacao proteins. Next, stool samples were collected, and the intestinal microbiota was analyzed by next-generation sequencing-based 16S rRNA. There was no significant difference in the α-diversity index of the gut microbiota between before and after ingestion of white chocolate, but the α-diversity index of the gut microbiota after ingestion of dark chocolate was significantly higher than before ingestion. The relative abundances of Faecalibacterium and Megamonas in the fecal microbiota after dark chocolate ingestion were significantly higher than before dark chocolate ingestion and significantly higher than after white chocolate ingestion. The relative abundances of Anaerostipes, Butyricicoccus, and Roseburia in the fecal microbiota after dark chocolate ingestion were significantly higher than before ingestion. Spearman correlation analysis revealed a correlation between the stool amount and relative abundances of Megamonas and Roseburia in the dark chocolate ingestion group. These results indicate that ingestion of dark chocolate improved constipation in humans and promoted increase of the relative abundances of butyrate producing bacteria such as Faecalibacterium, Megamonas, Anaerostipes, Butyricicoccus, and Roseburia in the intestinal microbiota.

Older individuals with care needs and lower body mass indices (BMIs) are more likely to be malnourished. Unintentional weight loss, an indicator of malnutrition, significantly impacts the physical function and poor prognosis of older adults. This study aimed to explore the effects of long-term consumption of Lacticaseibacillus paracasei strain Shirota-fermented milk (LcFM) on body weight in the oldest old among nursing-home residents. In total, 118 participants in 21 nursing homes were recruited. Owing to its preliminary nature, randomization and blinding were not conducted, and subjects in the intervention (consuming LcFM daily for 12 months) and non-intervention groups were recruited separately from different nursing homes. Changes in body weight and the proportion of participants with ≥5% body-weight loss were assessed at 6 and 12 months. As intergroup discrepancies in care-needs levels were observed at baseline, a subgroup analysis by these levels was conducted to align baseline characteristics. In the mild care-needs level subgroup (long-term care level ≤2), the LcFM group had a significantly lower proportion of participants with ≥5% weight loss than the control group. Additionally, a subgroup analysis by BMI demonstrated that an effect of LcFM on body weight decline was observed only in the subgroup with a BMI <22 kg/m², which indicates malnutrition risk in older adults. In conclusion, long-term consumption of LcFM might reduce unintentional weight loss in the institutionalized oldest-old individuals who have a risk of malnutrition and have a mild care-needs level. To confirm these preliminary results, further well-designed randomized trials will be required (UMIN000036684).

Certain probiotics prevent upper respiratory tract infections (URTIs) by activating immune cells, particularly mononuclear phagocytic cells (MPCs). However, the influence of Lacticaseibacillus paracasei strain Shirota (LcS), a representative probiotic strain, remains underexplored. This study aimed to investigate the effects of LcS ingestion on URTIs and MPC activation. Two hundred healthy workers aged 23–59 consumed a fermented milk drink containing 4.0 × 10¹⁰ CFU of LcS (LcS-FM) or a control unfermented milk drink (CM) daily for 28 days during winter. The incidence and severity of URTIs were surveyed using a questionnaire. Peripheral blood mononuclear cells (PBMCs) and serum samples were analyzed for immune cell subsets, cell surface molecules, and cytokines. The LcS-FM group showed a significantly lower incidence and severity of URTIs than the CM group. Notably, the incidence, cumulative incidence, and severity of URTI symptoms were markedly suppressed after 14 days of consumption. LcS-FM also affected MPC activation during this period. The expression of HLA-DR on conventional dendritic cells (cDCs) and monocytes (Mos) was significantly higher in the LcS-FM group on days 14 and 28, along with the expression of CD86 on cDCs on day 14. Among the study participants positive for serum interferon (IFN), the IFNα2 concentration in the LcS-FM group was higher than that in the CM group on day 28. These findings suggest that LcS suppresses the incidence and severity of URTIs in healthy adults, which is associated with the activation of cDCs and Mos.

Lactococcus lactis bacterium can be genetically modified to transport the spike protein from SARS-CoV-2, making it a potential candidate for a COVID-19 mucosal vaccine. This study aimed to optimize the nisin concentration, pH, incubation time, and media composition to induce spike protein expression. The concentrations of nisin used in this study ranged from 0 to 40 ng/mL, the incubation period was 3 to 24 hr, and the pH of the growth media ranged from 4 to 8. The media was also supplemented with various yeast extract and sucrose concentrations. The highest protein band intensity was observed at a concentration of 40 ng/mL and an incubation period of 9 hr. Supplementation with 4% w/v yeast extract and 6% w/v sucrose significantly increased the expression of HCR spike protein. In silico simulation suggested a maximal protein band intensity of 70.95 arbitrary units, while the nisin concentration needed to produce half the maximal protein band intensity was estimated to be 9.599 ng/mL. No significant difference in spike protein expression was found between pH variations. The media composition, inducer, and incubation time strongly affect the spike protein expression.

Dysmenorrhea, the most prevalent gynecologic complaint among adolescent females, often has unclear underlying causes. However, it is widely recognized that the accumulation of estrogen and prostaglandins mediates inflammatory responses, leading to uterine ischemia and pelvic pain. Emerging evidence highlights the significant role of intestinal flora as a key regulator of circulating estrogens, linking it to estrogen-modulated diseases. Our laboratory previously demonstrated that sclareol effectively alleviates uterine proliferation and mitigates pain. Nonetheless, the relationship between sclareol’s effects and gut microbiota modulation in dysmenorrhea remains unverified. To investigate this, we employed a mouse model induced with high doses of estradiol (1 mg/kg, IP) and administered sclareol (50 mg/kg, gavage) for five days. Fecal samples were subjected to 16S rDNA sequencing to analyze gut microbial composition. While no significant changes in alpha or beta diversity were observed, this study provides pioneering insights into sclareol’s impact on specific gut microbiota. Notably, sclareol treatment increased the abundances of Ruminococcus_1, Ruminococcaceae_UCG_013, Ruminococcaceae_UCG_014, and Streptococcus while reducing the abundances of Anaerotruncus and Lactobacillus at the genus level. These effects may be associated with alterations in short-chain fatty acids, β-glucuronidase activity, and overall intestinal health. In conclusion, this study identifies sclareol as a potential functional food candidate for the prevention and management of estrogen-modulated diseases through gut microbiota modulation. Further research is warranted to elucidate the underlying mechanisms and therapeutic applications.