Beneficial bacteria

The microbiome is home to “friendly” bacteria (commensal, beneficial) and potentially harmful ones (pathogens/pathobionts). The balance between them (eubiosis) determines gut health. The beneficial ones normally dominate.

A fresh angle (the stars of the microbiome): some beneficial bacteria are particularly valuable and well studied:

1. Faecalibacterium prausnitzii: one of the most abundant and important, a major producer of butyrate (anti-inflammatory). Its decline is a marker of dysbiosis and inflammatory diseases (Crohn’s). It is sometimes nicknamed the “sentinel of gut health”
2. Akkermansia muciniphila: lives in the mucus layer, which it helps to renew; linked to a better metabolic profile (weight, blood sugar). The subject of promising research on obesity and diabetes
3. Bifidobacterium and Lactobacillus: the best known (yoghurts, probiotics), they support digestion and immunity

What they do for us: beneficial bacteria are not mere passengers, they provide vital services:

1. Ferment fibre → SCFAs (butyrate) that nourish the gut lining
2. Synthesise vitamins (K2, some B vitamins)
3. Train and regulate the immune system
4. Hold their ground against pathogens (competitive exclusion)
5. Produce neurotransmitters (gut-brain axis)
6. Metabolise polyphenols into active compounds

How to encourage them:

1. Dietary variety: each type of fibre feeds different bacteria, so the more varied your diet, the more diverse and resilient your microbiome
2. Fibre and prebiotics (their food)
3. Fermented foods (a direct supply)
4. Polyphenols (fruit, colourful vegetables, tea)
5. Avoid what harms them: ultra-processed foods, excess sugar, unnecessary antibiotics, inactivity, chronic stress

The key idea: you do not simply “take” bacteria (probiotics), you cultivate a garden. The soil (diet, lifestyle) determines which bacteria thrive.