Im not a neuroscientist nor endocrinologist but i dont think it’s as simple as, your gut producing serotonin which travels to your brain and makes you happy.
I just googled this and found a pretty direct rebuttal:
The gut-brain axis is a bidirectional communication network that links the enteric and central nervous systems. This network is not only anatomical, but it extends to include endocrine, humoral, metabolic, and immune routes of communication as well. The autonomic nervous system, hypothalamic-pituitary-adrenal (HPA) axis, and nerves within the gastrointestinal tract, all link the gut and the brain, allowing the brain to influence intestinal activities, including activity of functional immune effector cells; and the gut to influence mood, cognition, and mental health.
pmc.ncbi.nlm.nih.gov/articles/PMC6469458/
As i said, I dont really know anything about this. However, there seems to be a large body of research supporting this hypothesis.
peopleproblems@lemmy.world 2 days ago
Most of the neurotransmitters can’t. That’s like one of the things the blood brain barrier does - keeps the chemicals IN the brain as well.
olafurp@lemmy.world 2 days ago
Fun exception is endocannabinoids, giving you a runners high when running.