In this episode of Learn Something with Thaena, we explore one of the most promising developments in microbiome oncology: whether reshaping the gut microbiome can improve response to cancer immunotherapy. We unpack the new FMT-LUMINate trial, a phase 2 study in patients with non-small cell lung cancer and melanoma, where a single dose of fecal microbiota transplant given before checkpoint inhibitor therapy was associated with striking response rates. But the most interesting finding was not simply donor bacteria “engrafting.” Instead, responders appeared to lose specific baseline bacterial species linked to resistance, suggesting that therapeutic benefit may come from removing deleterious microbes and restoring a more immune-supportive metabolic environment. We also discuss the earlier studies that built this field, the role of antibiotics, and why metabolites, not just microbes, may be the real mechanistic story.

Paper referenced:
Duttagupta S, Messaoudene M, Hunter S, et al. Fecal microbiota transplantation plus immunotherapy in non-small cell lung cancer and melanoma: the phase 2 FMT-LUMINate trial. Nature Medicine. 2026. doi:10.1038/s41591-025-04186-5.

In this episode of Learn Something with Thaena, we explore a striking new discovery in microbiome science: gut bacteria may help activate 5-ASA, a longstanding therapy used in inflammatory bowel disease. Drawing on a new preprint by Lamoureux and colleagues, we unpack how microbes can conjugate 5-ASA to bile acids, creating hybrid compounds such as cholyl-5-ASA that showed stronger anti-inflammatory activity than 5-ASA alone in cell assays and a mouse colitis model. The finding reframes a familiar drug as part of a larger microbial-host co-metabolic process, and raises a bigger question: how many other medications depend on the microbiome to work as intended?

Paper referenced:
Charron-Lamoureux V, Kelly P, Zuffa S, et al. Pan-repository analysis reveals a drug-activating function of microbial bile acid conjugation. bioRxiv. Posted March 4, 2026. doi: 10.64898/2026.03.03.709330.

Okay, real talk.

Have you ever taken an antibiotic, felt better in four days, and then completely forgot it ever happened?

Your gut definitely hasn't forgotten. A brand new 2026 study of nearly 15,000 Swedish adults just showed that a single course of antibiotics can leave a measurable mark on your gut microbiome for up to eight years. Clindamycin alone was associated with losing 47 species from one course. And the recovery curve? It flattens after two years — meaning if those species haven't come back by then, they probably aren't coming back. In this Lit Review Friday episode, we break down Baldanzi et al. (2026) from Nature Medicine, connect it to the landmark Suez et al. (2018) Cell study on why probiotics might actually delay recovery, and lay out what the science says about how to actually support your gut before, during, and after antibiotics.

🎙️ Hosted by AI Andrea and AI Jennifer Learn Something with Thaena uses AI to distill cutting-edge microbiome and health science into insights that are approachable, thought-provoking, and actionable.

🔬 Primary paper: Baldanzi G, et al. "Oral antibiotic use and the gut microbiome." Nature Medicine, 2026.

🌐 thaena.com

For years, we've been told gut health is about what you eat. But a landmark 2026 study just changed the conversation — and it starts with a vitamin nobody talks about.

In this Lit Review Friday, we break down a groundbreaking genetics study of over 268,000 people that identified the specific biological bottlenecks behind chronic constipation, bile acid diarrhea, and IBS. The headline finding? Two of the most significant genetic signals in the entire study pointed to vitamin B1 — not because people aren't eating enough of it, but because some people are genetically wired to struggle to use it.

We also cover the gut-brain genetics connection that links stool frequency to anxiety, depression, and bipolar disorder — not as separate conditions, but as different expressions of the same upstream biology.

If you or your patients have tried everything for gut motility and nothing sticks, this episode is for you.

Paper: Díaz-Muñoz et al., Gut, 2026.

We open with a confession: years of believing the microbiome is everything — and one genetics paper that forced a rethink.

This week on Lit Review Friday, we dig into a major genome-wide association study just published in the journal Gut by Díaz-Muñoz and colleagues. They analyzed over 268,000 people across European and East Asian populations to find the genetic architecture behind something deceptively simple: how often people have bowel movements. What they found was anything but simple.

In this episode:

🔬 What a GWAS actually is — and why stool frequency makes a surprisingly powerful research tool

💊 The KLB gene and bile acid diarrhea — why some people are genetically wired for urgency and loose stools, and why telling them to "manage stress" misses the point entirely

⚡ The enteric nervous system's "go" signal — and the gene that controls how long it lingers

🧬 The bombshell: the two most precisely identified genetic variants in the whole study both landed on vitamin B1 (thiamine) — specifically on the cellular door that lets B1 in, and the machinery that activates it once it's inside

📊 UK Biobank data showing that dietary thiamine does improve bowel regularity — but only if your genes let you use it

🧠 The gut-brain genetics connection: why IBS-C, anxiety, depression, and bipolar disorder share overlapping genetic architecture — and what that means for how we treat them

💉 What to do if diet alone isn't enough: benfotiamine, IV delivery, postbiotics, dysbiosis reduction, and the case for alternative absorption routes — including a very personal home hot springs situation

The through line: Your genes set the floor. Your microbiome is the environment those genes are operating in. A person with a sluggish B1 transporter and a depleted microbiome is fighting a two-front battle — and most treatment protocols only address one.

Research Discussed:Díaz-Muñoz C, et al. "Genetic dissection of stool frequency implicates vitamin B1 metabolism and other actionable pathways in the modulation of gut motility." Gut, 2026. doi:10.1136/gutjnl-2025-337059

Keywords: IBS, constipation, gut motility, thiamine, vitamin B1, GWAS, bile acid diarrhea, gut-brain axis, microbiome genetics, IBS treatment, functional medicine, anxiety and gut health, KLB gene, benfotiamine, postbiotics

What can a bok choy field in China teach us about healing the human gut? In this episode, Andrea and AI Jennifer unpack a 2025 study that compares manure, biochar, and chemical fertilizer, and tracks how each one reshapes soil microbes and antibiotic resistance genes. Using two neighboring farms as a metaphor, they explore why “more bacteria” is not a strategy, how context determines whether an intervention is regenerative or risky, and what this means for probiotics, postbiotics, and rebuilding a depleted microbiome. If your gut feels like overworked soil, this episode offers a new way to think about scaffolding, not just supplements.

Thaena Companion Blog with Intervention Menu

Paper reference

Li K, ur Rahman S, Rehman A, et al. [Full title as in journal]. Journal of Hazardous Materials. 2025;487:137148.
https://doi.org/10.1016/j.jhazmat.2025.137148

We’ve joked about “poop toothpaste” for years—today we bring data. This episode dives into a new human study using a heat-killed Enterococcus faecalis (EF-2001) toothpaste/paste approach in 137 people with tough oral conditions. About 65% reported better oral symptoms—often within 2–4 weeks—and, notably, ~65% with gut complaints also improved over 4–8 weeks. Those oral gains significantly tracked with GI improvements, hinting at the oral–gut axis in real life. We unpack why non-live, postbiotic strategies (plus gentle prebiotics and contact time) may shift biofilms, cool inflammation, and offer a safer, ecosystem-friendly path than scorched-earth antimicrobials—while acknowledging the study’s open-label limits and the need for blinded RCTs.

References:

• Minabe M, Ueno S, Hata K, et al. Questionnaire Survey on Enterococcus faecalis-2001 Supplementation in 137 Patients With Oral Diseases at Two Facilities. Cureus. 2025;17(9):e91382. doi:10.7759/cureus.91382.

Historically, humans ate 60–100 grams of fiber daily. Today, most Western diets hover around 5–20 grams. This dramatic loss is thought to be a root cause of our microbiome collapse and the rise in chronic disease.

But here’s the twist: the very fiber that heals some people may actually harm others. In this episode of Learn Something with Thaena, Andrea and Jennifer dive into the fiber paradox—where fiber is both hero and potential villain depending on the gut ecosystem.

• How Jung et al. (2025) showed inulin reversed fructose-driven fatty liver disease in mice.

• Why Singh et al. (2018) found the same fiber triggered liver cancer in mice with dysbiotic guts.

• The Gardner, Fragiadakis & Sonnenburg (2021) study in humans: fiber reduced inflammation in diverse microbiomes but increased it in low-diversity ones.

• Why fermented foods—yogurt, kimchi, kombucha—boost diversity and reduce inflammation regardless of baseline.

• How Formiga et al. (2025) with Harry Sokol revealed cadaverine, a microbial metabolite, is anti-inflammatory at low doses but harmful at high concentrations.

• Why context, dose, and diversity are the keys to understanding fiber’s double-edged role.

1. Jung Y et al. Nature Metabolism. 2025. Inulin protects against fructose-induced fatty liver disease.

2. Singh V et al. Cell. 2018. Dysregulated fermentation of soluble fiber induces cholestatic liver cancer.

3. Fragiadakis GK, Wastyk HC, Sonnenburg ED, Gardner CD, Sonnenburg JL. Cell. 2021. Fermented foods vs. high-fiber diets in humans: impacts on microbiome and inflammation.

4. Formiga RO, Sokol H et al. Cell Host & Microbe. 2025. Cadaverine as a context-dependent microbial metabolite.

Fiber is still a hero—but it needs the right supporting cast. In depleted, industrialized microbiomes, fiber alone might not save the day. Paired with fermented foods, postbiotics, and personalized approaches, it can once again become the powerhouse nutrient it was meant to be.

👉 If you enjoyed this episode, share it with a friend, a clinician, or someone grappling with the fiber paradox.
🔗 Learn more at Thaena.com.

🔑 What You’ll Learn📚 References🌱 Key Takeaway

A new Lancet study is shaking up how we think about fecal transplants. What does a sterile filtrate — poop without live bacteria — represent when challenged by traditional FMT in a clinical trial of C.diff?

AI Andrea breaks down the history, science, safety, and future of FMT, from phages to postbiotics.

Kao et.al., (2025). Effects of lyophilised faecal filtrate compared with lyophilised donor stool on Clostridioides difficile recurrence: a multicentre, randomised, double-blinded, non-inferiority trial. The Lancet. Gastroenterology & Hepatology, 0(0). https://doi.org/10.1016/s2468-1253(25)00190-6