Not Fixed, Still here
There's a particular kind of exhaustion that sleep doesn't fix. A particular kind of struggle that therapy helps but doesn't solve. A particular kind of life that doesn't follow the recovery arc.
Not Fixed, Still Here is a podcast about mental health—all of it grounded in science, shaped by lived experience, and honest about the gaps in between.
Hosted by someone who has navigated depression, emotional and physical abuse, and over two decades of asking challenging questions about the mind, this show brings together psychology, neuroscience, and the therapeutic frameworks that actually helped—CBT, DBT, EFT, and NLP—not to tell you what to do, but to help you understand what's happening and why.
Every episode moves between the research and the reality. The science is real. The uncertainty is named. And nothing gets wrapped up too cleanly.
This is not a wellness show. It is not therapy. It is not a recovery story with a tidy ending.
This conversation is for those who are intellectually curious, emotionally exhausted, and tired of receiving easy answers.
Not Fixed, Still Here. The science of mental health, without the performance. If this show means something to you, you can support it here: Toren "TY" Ylfa
If you or someone you know is struggling, support is available 24/7. Call or text 988 (Suicide and Crisis Lifeline) or text HOME to 741741 (Crisis Text Line).
Not Fixed, Still here
Your Gut Knows Something Your Doctor Doesn't
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Your gut and your mood move together. You've probably noticed.
The stomach that doesn't feel right when you're anxious. The appetite that disappears when the depression is heavy. The physical dimension of something that's supposed to live entirely in the mind.
You were noticing something real.
Approximately 95% of the body's serotonin is produced in the gut — not the brain. The gut communicates with the brain through the vagus nerve, the immune system, and microbial metabolites that directly influence brain chemistry. And a 2025 Mendelian randomization study — one of the most rigorous designs for testing causation — found that gut microbiota dysbiosis is a causative factor in depression and anxiety, not merely a side effect of them.
This episode goes into what the gut-brain axis actually is, what the serotonin finding really means, what the research on probiotics and the microbiome genuinely shows — and where the honest limits of all of it are.
The science here is significant. And some of what's being sold on the basis of it moves faster than the evidence. Both things are true.
Not Fixed, Still Here. Episode 8.
Resources referenced in this episode:
Lai & Xiong — Gut microbiota dysbiosis as a causative factor in depression and anxiety (Frontiers in Microbiology, 2025): frontiersin.org
BMC Psychiatry — Probiotics, prebiotics, and synbiotics for anxiety and depression: systematic review and meta-analysis (November 2025): link.springer.com
PMC — The Immune Mind: Dietary Patterns, Microbiota, and Psychological Health (2025): pmc.ncbi.nlm.nih.gov
Frontiers in Psychiatry — The gut-brain-circadian axis in anxiety and depression (2025): frontiersin.org
If anything in this episode brought something up for you, support is available 24/7.
Call or text 988 — Suicide and Crisis Lifeline — free and confidential, any time.
Text HOME to 741741 — Crisis Text Line — free and confidential, any time.
Approximately ninety-five percent of the body's serotonin is produced in the gut, not the brain, the gut. That single fact, which is well established, not contested, and has been known for decades, changes something about how we think about mental health. If serotonin is central to mood regulation and most serotonin is produced in the gut, then the gut is not just a digestive organ, it is a participant in your mental health. The question is what that means and the answer is more complicated, more interesting, and more uncertain than most of what you'll hear about it. Today we are going to go there.
SPEAKER_00A podcast about mental health founded in science and I am Torin, not a therapist, not a clinician, someone who has spent 20 years inside these questions. And this is what happens when I ask them out loud. This episode is episode eight, and I want to prepare from the outset about what a kind of episode this is. The science here is real, substantial, and genuinely changing how we understand the relationship between the body and the mind. It is also one of the most heavily marketed areas in the biology industry, probics, psychobotics, methods, what the particles, the commercial ecosystem, and only science, is it enormous and learning. This episode is going to give you the after science, what the research is, I think it doesn't understand where the line sits between what we genuinely know and what is being shown on the basis of what we know.
SPEAKER_01I want to start with something that many people who have lived with depression for a long time will recognise. The physical dimension of it. Not just the heaviness in the mind, the heaviness in the body, the stomach that doesn't feel right, the appetite that disappears or becomes relentless, the gut that seems to respond to emotional states before the brain has fully registered them. If you have noticed that your gut and your mood seem to move together, that anxiety lives somewhere in your stomach. That depression dulls your appetite, that certain foods change how you feel in ways that seem to go beyond digestion. You are noticing something real. The relationship between the gut and the brain is not a metaphor, it is a biological reality. And the research into it is one of the most exciting developments in mental health science in recent years. The question is what we can actually do with it, and that is where things get complicated. The usual frame before we go in. I am not a gastroenterologist or a microbiologist. Everything that I share today comes from published peer reviewed research sources are in the show notes. I want to hold the same standard I've held across the series. What is then established I'll say so. What is emerging and promising or name it as that, what is contested or clear, I'll say that too. This episode covers four things first what the gut of brain access actually is and how the communication between them works. Second, the serotonin question what the gut has to do with it and what that means for mental health. Third, what the research on probiotics and the gut microbiome actually shows for depression and anxiety. Fourth, what we can reasonably take from all of this and where the honest limits of that are. Which leads us to the microbiome itself. The gut microbiome is the community of trillions of microorganisms living in the digestive tract, bacteria, viruses, fungi, archaea, approximately 1,000 different species. Each person's microbiome is unique, shaped by genetics, birth, diet, medication, stress and environment. And the research connecting microbiome health to mental health is one of the most rapidly developing areas in all of medicine. Frontiers in Microbiology 2025 Systematic Review. Studies involving animal and human subjects suggest an association between gut microbial diversity and mental health, indicating that microbiota disturbances may contribute to depression onset. People with depression often show lower levels of SCFA producing bacteria, higher levels of pro-inflammatory bacteria, increased intestinal permeability, altered tryptophan metabolism. Early life stress causes significant changes in gut microbiome composition, and these changes appear to mediate some of the neuropsychiatric effects of that stress. That Mendelian randomization finding is particularly significant. Causative, not merely correlational. The microbiome dysbiosis appears to be contributing to depression, not just occurring alongside it. That is an important step forward in the science. It moves this from an interesting association to a potential mechanistic battery. Now what does that mean for treatment? What can we actually do with this information? This is where the research gets more cautious and where the science and the marketing begin to diverge. Probiotics and mental health the evidence and its limits systematic review and meta analysis BMC Psychiatry november twenty twenty five pre probiotics showed significant effects on anxiety and depression symptoms in a randomized controlled trials. The majority of recent literature suggests a beneficial role of probiotics in the treatment of depression and anxiety despite the existence of a substantial number of less positive findings. But the same reviews consistently note there is a lack of consistent findings, variability in treatment approaches and clinical presentations, limits the comparability and generalization of findings. The lack of standardization in dosing and strain selection in addition to the scarcity of large scale clinical studies limits the applicability of these findings in clinical therapy. Translation probatic so promising but inconsistent effects which specific strains at what dose for how long for which presentations these are not yet established. Promising but inconsistent. That phrase is doing important work. It is not a dismissal of the evidence, it is an honest description of where the evidence currently sits. The signal is real, the research is showing effects. But we do not yet know enough to say with confidence which probiotic in which dose for which person with which presentation for how long will produce a meaningful sustained benefit for depression or anxiety. And that gap between this is a real and seasonal, never good area of science, and by this specific supplement supplement and feel better is exactly the gap we examined across the last two episodes. So what can we reasonably take from all this? I want to be careful not to leave this episode in the same place that episodes six and seven ended with caution and critique. Because the gut-brain axis science genuinely offers something that is worth holding. The first thing is conceptual. Mental health is not just a brain problem, it is a whole body condition. The gut, the immune system, the inflammatory response, the vagus nerve, the microbiome, these are not peripheral to mental health. They are a part of its biology. That reframe has value independent of any specific intervention. It means that when we talk about mental health, we are talking about the whole body, not just what happens between the ears. The second thing is more practical. The research consistently finds that certain things support a healthy gut microbiome and the same things are independently associated with better mental health outcomes. What consistently supports the gut brain access current evidence? Well established, consistent across multiple studies, dietary diversity, wide variety of whole foods, fibre intake feeds SCFA producing bacteria, fermented foods, natural probiotics, yogurt, kefir, kimchi, sauerkraut and miso, reduced ultra processed food intake, UPF associated with increased risk of common mental disorders, umbrella review 2024, physical exercise directly modulates microbiome composition and independently of support mood, reduced antibiotic overuse, preserves microbiodiversity, emerging, promising but not yet established as clinical guidance, specific probiotic strings, particularly lactobacculus, vividobacterium species, prebiotic supplementation, fake or microbata transplantation FMT for depression, early human trials showing antidepressants effects. I want to sit with the ultra-processed food finding for a moment because it is one of the most robust in this area. A 2024 umbrella review, a review of reviews, found a consistent dose response association between ultra-processed food intake and risk of common mental disorders. Dose response means the more UPF consumed, the higher the risk. That is a strong epidemiological signal. It does not mean that ultra-processed food causes depression. The relationship is almost certainly bidirectional. Depression affects what people eat and what people eat affects depression. But the association is consistent and significant. And it points towards something accessible. Dietary choices that support microbiome health are also choices that the evidence independently associates with mental health. I started this episode with a fact 95% of the body's serotonin is produced in the gut. I want to close with what that fact actually means. It means that the separation between mind and body that had dominated her rethink. About mental health, the idea that depression is a brain problem with brain solutions is not the whole picture. Mental health is a whole body condition, the gut is involved, the immune system is involved, the inflammatory response is involved, what you eat, how you move, what you were exposed to in your life. These are not separate for your mental health, they are a part of its biology. That does not mean a probiotic will lift your depression. The research is not there yet, but it does mean that mental health is a more whole body question than the systems designed to treat it have historically acknowledged. And that framing that the whole body is involved is one worth carrying. Next episode, we are going to look at AI and mental health, what artificial intelligence is already doing in the mental health space and the particular dangers of using it to diagnose itself. But for now that's enough. You can call or text 988 the suicide and crisis lifeline. Free confidential available 24 hours a day. Or text home to 741 741. The Crisis Techline, also free, confidential, and available anytime. You can find this show wherever you listen to your podcasts. If today's episode meant something to you, please show it with someone who might need it. I'm Toman, I'll be back for episode nine. Take care of yourself.