Sex- and Gender-related Issues of Gut Microbiota in Gastrointestinal Tract Diseases

The distribution of gut microbiota varies according to age and sex. Gut microbiota are known to contribute to gastrointestinal (GI) diseases such as irritable bowel syndrome, inflammatory bowel disease, and colon cancer; however, the exact etiology remains elusive. Sex hormone such as estrogen and testosterone control the microbiota mainly due to different effect on the immunity. In addition, the diet depending on gender also affect the gut microbiota. Furthermore, the metabolism of estrogen and androgen was reported to be related to the gut microbiome. However, there have been few comprehensive review articles regarding the effect of microbiota on GI diseases. In this review, the factors which affect the gut microbiota and the interplay of microbiota and GI diseases in terms of sex- and gender differences were briefly summarized