← Back to all research
The gut microbiome—the 38 trillion bacteria, archaea, fungi, and viruses in your intestinal tract—is not passive. It produces neurotransmitters, regulates immune function, metabolizes nutrients, and communicates with the brain via the vagus nerve. With age, microbiome diversity declines sharply, and this decline is increasingly linked to inflammaging, metabolic dysfunction, and accelerated aging. Here is what the science shows about how to protect and restore it.
Evidence Assessment
Evidence Strength
Moderate
Study Type
Clinical Review
Confidence
High
Key Findings
- Butyrate-producing bacteria decline with age, weakening the gut barrier and driving systemic inflammation
- Fermented foods outperformed high-fiber diets for immune marker improvements in a Cell 2022 RCT
- Mediterranean diet for one year increased protective gut species and reduced IL-6 in older adults (Ghosh et al., Gut 2020)
- FMT from aged mice to young mice produces premature cognitive aging—demonstrating causal role
Practical Takeaways
- Aim for 30g+ dietary fiber per day from diverse plant foods
- Eat at least one fermented food daily (kefir, kimchi, sauerkraut, yogurt)
- Minimize ultra-processed foods and unnecessary antibiotics
Limitations & Caveats
- Causality between microbiome and aging outcomes not fully established
- Most probiotic supplements have weak evidence in healthy adults