Effects of probiotic supplementation on testosterone levels in healthy ageing men: A 12-week double-blind, placebo-controlled randomized clinical trial.

Levels of the male sex hormone testosterone are generally stable in the age interval 20-70 years, but several studies indicate an earlier, age-dependent decline. Testosterone deficiency is often underdiagnosed and under-treated, but replacement therapy has nonetheless increased during the last couple of years. Owing to possible negative side effects, alternative treatments have been investigated, including different supplementation protocols. The aim of this study was to investigate the effect of probiotic supplementation on the testosterone level in healthy men aged between 55 and 65. Hence, 12 weeks randomized, double-blinded, placebo-controlled trial was conducted to investigate the effect on testosterone levels following supplementation of the recognized probiotic Limosilactobacillus reuteri ATCC PTA 6475 on testosterone levels, using high-, low- or placebo treatment. Venous blood samples were collected at baseline, 6 and 12 weeks, for analysis of bloodwork, lipid profile, hormones, and electrolytes. Subjects were also asked to complete a questionnaire. The supplementation had no effect on testosterone levels, neither using high- or low dose, nor placebo. However, a significant decrease of triglyceride levels was observed in the high-dose group. No other parameters showed any significant change. The present study does not support the hypothesis that a probiotic supplementation can increase testosterone levels in ageing men.

Oral Biofilm Composition, Dissemination to Keratinocytes, and Inflammatory Attenuation Depend on Probiotic and Synbiotic Strain Specificity.

Several inflammatory diseases are characterized by a disruption in the equilibrium between the host and its microbiome. Due to the increase in resistance, the use of antibiotics for the widespread, nonspecific killing of microorganisms is at risk. Pro-microbial approaches focused on stimulating or introducing beneficial species antagonistic toward pathobionts may be a viable alternative for restoring the host-microbiome equilibrium. Unfortunately, not all potential probiotic or synbiotic species and even subspecies (to strain level) are equally effective for the designated pathology, leading to conflicting accounts of their efficacy. To assess the extent of these species- and strain-specific effects, 13 probiotic candidates were evaluated for their probiotic and synbiotic potential with glycerol on in vitro oral biofilms, dissemination from biofilms to keratinocytes, and anti-inflammatory activity. Species- and strain-specific effects and efficacies were observed in how they functioned as probiotics or synbiotics by influencing oral pathobionts and commensals within biofilms and affected the dissemination of pathobionts to keratinocytes, ranging from ineffective strains to strains that reduced pathobionts by 3 + log. In addition, a minority of the candidates exhibited the ability to mitigate the inflammatory response of LPS-stimulated monocytes. For a comprehensive assessment of probiotic therapy for oral health, a judicious selection of fully characterized probiotic strains that are specifically tailored to the designated pathology is required. This approach aims to challenge the prevailing perception of probiotics, shifting the focus away from "form over function." Rather than using unproven, hypothetical probiotic strains from known genera or species, one should choose strains that are actually functional in resolving the desired pathology before labelling them probiotics.