Small intestinal bacterial overgrowth (SIBO) as a potential cause of impaired spermatogenesis

We commend Ding and colleagues for their innovative work investigating how high-fat diet-induced changes to the gut microbiome can alter spermatogenesis.1 This link between the gut microbiome and testicular function had earlier been suggested by studies that reported the consumption of probiotic bacteria could improve spermatogenesis and testosterone production in both mice and men.2 3 Furthermore, we had earlier published the Gut Endotoxin Leading to a Decline IN Gonadal function (GELDING) theory that outlined the scientific evidence behind why obesity related change in the gut microbiome, and the associated increase in intestinal permeability with passage of gut bacterial endotoxin (metabolic endotoxaemia, ME) into the systemic circulation, may impair testicular function.4 Since that publication we have gone on to show that obesity related ME is associated with low-grade systemic inflammation, reduction in testosterone production and impaired sperm quality5 6—all consistent with the probiotic studies2 3 and the experimental findings of Ding …