03/27/2025
Let’s talk about that “95% of serotonin is made in your gut” stat.
Yes, it’s true that the majority of the body’s serotonin is produced in the gut — but here’s the key:
That serotonin is made by specialized cells in the digestive system (called enterochromaffin cells), and it cannot cross the blood-brain barrier.
The serotonin that affects your mood? That’s produced in the brain stem, and it stays within the central nervous system. These are two completely separate pools of serotonin, functioning differently in different parts of the body.
So when we hear, “most of your serotonin is in your gut, therefore gut health = better mental health” — we’re skipping over a lot of important nuance.
And here’s the bigger question:
We already know that low serotonin isn’t the root cause of depression… so why are we still focusing so much on a single neurotransmitter?
👉🏽 Does that mean diet and gut health have nothing to do with mental health?
Not at all. But we need more research — and we’re not quite there yet.
That said, there are so many other reasons to care about nutrition for overall health. There’s important research happening around inflammation, the gut-brain axis, and disorders of gut-brain interaction — and how it might all tie into this big, complex web of mental health (because yes… it’s always more complicated than we’d like).
But catchy slogans like “happy gut, happy mind” can oversimplify what’s actually a very complex system — and sometimes leave people more confused than empowered. In some cases, I think it even steers people down the wrong path for treatment.
(For now, at least… I’d love to see the research evolve!)
So, should you still focus on eating a well-balanced diet, a wide variety of fruits and veggies, and getting plenty of fiber (if your digestion allows)?
Yes. Always yes.
But let’s not pin our entire understanding of mental health on one neurotransmitter — especially one that isn’t even crossing into the brain — or promote something that just isn’t true (at least not yet!).
More on this soon — especially the real ways the gut-brain connection might matter.