Live Well Be Well with Sarah Ann Macklin | Health, Lifestyle, Nutrition The Brain Has Bacteria? What the Brain Microbiome Means for Health and Longevity | William Li
Jan 16, 2026
In this engaging discussion, Dr. William Li, a physician and researcher renowned for his work on beneficial microbes, reveals astonishing insights about the brain microbiome. He explains how once-thought-sterile areas, like the brain and breast milk, host helpful bacteria. The conversation dives into gut-brain communication through the vagus nerve and the importance of seeing bacteria as mostly beneficial rather than harmful. Li emphasizes the need for humility in medicine, urging listeners to tune into their bodies and adopt biohacking strategies for better health.
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Sterile-Body Dogma Is Falling Apart
- Medicine once taught many body sites were sterile, but that view is changing rapidly.
- Discoveries show sites like breast milk and the bladder host beneficial bacteria that shape health.
Medical Training: 'Must Kill Bacteria'
- In medical school William Li recalls being taught 'must kill bacteria' alongside memorizing microbes.
- He now emphasizes most bacteria are beneficial, not enemies to be eliminated.
Examples Of Previously 'Sterile' Sites
- William Li describes examples once thought sterile: mother's milk and urine, both actually contain microbes.
- He frames bladder infections as dysbiosis, a disturbance of a normally healthy microbiome.