Men’s Health

Where the Gut Fits Into Men's Health

The conditions grouped under men's health look unrelated to the intestine. Prostates, muscle, fertility and hormones sit a long way from the gut. What connects them is that gut bacteria manufacture and modify hormones, influence the inflammatory background every tissue sits in, and shape how efficiently protein from food becomes muscle. In one case here, gut bacteria don't just influence a condition. They actively undermine its standard treatment.

Hormones, muscle and inflammation

The most striking finding concerns treatment resistance. Advanced prostate cancer is treated by cutting off androgens, the male sex hormones the tumour depends on. It works until it doesn't. Researchers found that starting that treatment expands gut bacteria capable of manufacturing androgens themselves. Clearing those bacteria with antibiotics delayed resistance across four separate mouse models, including in animals with no working immune system, and transplanting bacteria from resistant patients transferred the resistance to mice.

Muscle follows a different route. A systematic review gathered 26 pre-clinical and 10 clinical studies, and in 75% of the faecal transplant studies recipient mice took on the muscle characteristics of the donor. Germ-free animals show muscle atrophy, lower growth hormone signalling and worse mitochondrial function, all reversed by giving them bacteria.

Chronic pelvic pain shows a third pattern. Comparing 25 men with the condition against 25 without found significantly less varied gut bacteria in the patients, with one group depleted enough that researchers proposed it as a marker.

Fertility involves bacteria closer to home. Semen carries its own bacterial community, and among men with poor sperm motility one species made up 9.4% of it, against 2.6% in men whose sperm swam normally.

Source: Commensal bacteria promote endocrine resistance in prostate cancer through androgen biosynthesis

Source: Understanding the gut microbiota and sarcopenia: a systematic review

Source: Semen microbiota are dramatically altered in men with abnormal sperm parameters

What this means for you

Urinary changes, pelvic pain, difficulty conceiving or losing strength faster than expected are all worth raising with a doctor rather than waiting, since several causes are treatable and prostate problems in particular need proper assessment. In addition, the research above shows gut bacteria manufacturing the hormones prostate cancer treatment is designed to remove, carrying muscle characteristics between animals in three quarters of transplant studies, and differing measurably in men with chronic pelvic pain. A varied, plant-rich diet supports the same gut bacteria this research ties to steadier hormone handling and better preserved muscle. That's the same idea behind GutLab, everyday gut health starts with regularly feeding the microbiome a broad range of plant-rich ingredients.

Explore men's health topics on this page

The panels on this page cover conditions connected to the gut by different mechanisms, and the evidence is stronger for some than others.

Prostate cancer has the most developed evidence, concerning resistance to treatment rather than whether the cancer starts. Muscle loss rests largely on transplant experiments in animals, with human work still catching up.

Prostatitis and sperm quality concern bacterial communities measured directly in affected men, both from small studies that need replication.

Use the panels on this page to find the one relevant to you.