References – MN 17: Jungle Thickets 
“How do discoveries about the gut microbiome fit in with the Buddha’s teachings?” Answered by Ajahn Pasanno. [Science] [Dhamma] // [Not-self] [Self-identity view] [Mindfulness of body] [Clear comprehension] [Naturalness]
Follow-up: “How does the relate to monks who subsist on almsfood and sometimes don’t get enough, considering that the gut is controlling the brain?” [Monastic life] [Almsfood] [Health] [Ajahn Soṇa] [Mutual lay/Saṅgha support]
Sutta: MN 17: Vanapattha Sutta.