Association Between Sex Hormone Levels and Gut Microbiota Composition and Diversity—A Systematic Review

Abstract

Goals/Background: Animal studies have highlighted how the microbiota acts in a sex-specific manner with sex hormones demonstrating an association with the composition and diversity of the microbiota. This systematic review aimed to gather the available scientific evidence to explore the association between sex hormones and gut microbiota composition and diversity, in humans. Study: Four bibliographic databases were searched in July 2020 using terms related to “microbiota,” “microflora,” “sex hormones,” “testosterone,” and “estrogen.” Human studies that investigated the correlation between sex hormones and the microbiota composition or diversity using next-generation sequencing were included. Results: A total of 10,468 records were screened with 13 studies included in this review. In healthy women, higher estrogen levels were found to be associated with a higher abundance of Bacteroidetes, a lower abundance of Firmicutes, the Ruminococcaceae family and increased diversity. In healthy men, raised testosterone levels positively correlated with Ruminococcus, Acinetobacter, and an increased microbial diversity. Escherichia and Shigella spp. were correlated with raised testosterone in healthy women whereas Ruminococcus spp. was negatively associated with elevated testosterone levels. Women with altered testosterone/estrogen profiles (such as in polycystic ovary syndrome), had a differing gut microbiota compared with healthy women. Conclusions: The findings gathered highlight an association between sex hormones and the gut microbiota composition/diversity and may contribute to the sex-based variations observed in disease pathogenesis. Factors such as age and medical conditions are implicated in the associations observed and should be accounted for in future studies. As the understanding of the complex symbiotic relationship between humans and their gut microbiota increases, microbiota modulation could be an attractive option for the prevention and treatment of gastrointestinal disorders.

Multicompartmental traumatic injury and the microbiome: Shift to a pathobiome

“…In addition, we only evaluated microbiome and intestinal change in male rats; going forward, it will be important to assess sex differences between males and females. Sex has been proven to influence the microbiome, and one study had already demonstrated unique microbial composition between sexes in the setting of murine sepsis 49,50 . Finally, this study was only of rats aged 9 to 11 weeks; further studies on the potential influence of age on intestinal dysbiosis after trauma should be considered.…”

Gender-related differences in the effects of Inonotus obliquus polysaccharide on intestinal microorganisms in SD rats model

“…The results showed that there were differences in the regulation of intestinal microflora between male and female SD rats after Inonotus obliquus consumption, with these observations being consistent with a previous study which reported opposite changes in the correlation of α-diversity in the intestinal microflora of male and female SD rats ( 42 ). Similarly, as far as humans are concerned, sex-related differences such as total estradiol levels were shown to be negatively correlated with α diversity in healthy men, non-hyperandrogenic women as well as women with polycystic ovary syndrome (PCOS) ( 43 ).…”

“…Roseburia was significantly more abundant in females than in males. This genus is able to utilize fructan and increase glucagon-like peptide-1, thereby reducing the risk of obesity ( 43 ), with this function being important as obesity has been reported to promote high androgen production, which could lead to the development of polycystic ovarian syndrome ( 47 ). Based on the results, it was further speculated that Roseburia could reduce the secretion of sex hormones.…”

“…Based on the results, it was further speculated that Roseburia could reduce the secretion of sex hormones. In male rats that were given IOP, Muribaculaceae ( 48 ), which can regulate testosterone induced benign prostatic hyperplasia ( 43 , 49 ). However, Prevotella , which was positively correlated with testosterone, was higher in abundance than in females while the F/B ratio was lower compared with that of females.…”

Estrogen receptor β deficiency impairs gut microbiota: a possible mechanism of IBD-induced anxiety-like behavior

“…The composition of gut microbiota remains relatively constant throughout the adult life and may be altered under circumstances that subsequently influence the host’s health status [ 14 ]. Intriguingly, the different levels of sex hormones, including testosterone and estradiol, are correlated with the diversity and composition of gut microbiota in humans, indicating an association between sex hormones and gut microbiota [ 15 ]. Estrogen receptor (ER) β is an important ligand-activated nuclear transcription factor involved in estrogen signaling, and it is the predominant ER subtype in colon tissue where it plays an important role in colonic mucosal homeostasis by maintaining the integrity of tight junctions and the barrier function [ 16 , 17 ].…”