Irritable bowel syndrome (IBS) is a heterogeneous disorder affecting 5–10% of adults worldwide and is characterized by recurrent abdominal pain, bloating, and altered bowel habits. Traditional dietary approaches—most notably the low‑FODMAP diet—help many patients but can reduce microbial diversity and may not suit everyone. Emerging work tests whether tailoring diets to an individual’s gut microbiome can deliver more precise, durable symptom relief. Microbiome insights and mechanisms IBS cohorts commonly show reduced microbial diversity with lower levels of beneficial taxa (e.g., Bifidobacterium, Faecalibacterium) and relative increases in Proteobacteria and some Ruminococcus species. These shifts can promote excessive gas production, immune activation via microbial metabolites, increased intestinal permeability, and altered brain–gut signaling—mechanisms plausibly linked to core IBS symptoms. Evidence from traditional diets Controlled trials support symptom benefit from low‑FODMAP and, to a lesser extent, Mediterranean and elemental diets. The low‑FODMAP protocol often leads to rapid symptom improvement but also transient declines in microbial richness; Mediterranean‑style eating has shown similar symptom reductions with a less restrictive profile and more favorable effects on microbiome composition. Microbiome‑based personalized nutrition: what trials show Several pilot studies and recent randomized trials have evaluated AI‑driven or microbiome‑informed dietary programs. In a multicenter randomized trial, an AI‑assisted personalized diet reduced IBS symptom scores comparably to low‑FODMAP while also increasing microbial diversity and Faecalibacterium prausnitzii and reducing some Ruminococcus species—changes not observed in the low‑FODMAP arm. Smaller pilots and company‑led studies (including Enbiosis and digital nutrition trials) report symptom improvements and taxonomic shifts such as decreased Veillonella or increased Akkermansia in some participants. How personalization is operationalized Workflows typically combine stool sampling (16S or shotgun sequencing), predictive modeling, and diet tailoring that adjusts fiber types, macro/micronutrient balance, and targeted probiotic or prebiotic recommendations. Delivery is often app‑based or clinician‑mediated with ongoing symptom tracking and repeat microbiome monitoring. Strengths, limitations, and risks Potential strengths include restoring diversity rather than broadly restricting it, targeting symptom‑relevant microbial pathways, and improving adherence through individualized plans. Limitations include small sample sizes, short follow‑up (≤12 weeks in many studies), cost/access issues, and privacy considerations around microbiome data. Risks include overly restrictive recommendations that risk nutrient shortfalls and uncertain long‑term safety of directed microbiome modulation. Clinical implications and next steps Microbiome‑based personalization is a promising complementary strategy for patients who do not fully respond to conventional dietary strategies. Larger, longer randomized trials, integration of metabolomic/proteomic data, real‑time digital tracking, and ethical/regulatory frameworks for AI‑driven diets are needed to define clinical utility and safety. For an accessible synthesis of clinical evidence and recent trials, see the discussion of personalized microbiome nutrition in this review: [personalized microbiome nutrition for IBS](https://www.innerbuddies.com/blogs/irritable-bowel-syndrome-ibs/personalized-microbiome-nutrition-ibs-evidence). Further reading on how microbial differences shape probiotic needs is available at how your unique microbiome dictates your probiotic needs and on broader community dynamics at gut microbiome: the good, the bad, and the ugly. A related testing resource can be found at microbiome test. Overall, microbiome‑informed diets offer a rational, evidence‑informed pathway toward precision nutrition in IBS, but they should be applied within a multidisciplinary, patient‑centered framework and paired with rigorous monitoring.