Home › Organ system
Organ systemMicrobiome
The microbiome is the collection of bacteria in your gut. They help digestion, train your immune system and make substances that influence your health.
Microbiome at a glance
WhatThe bacteria in your gut
ImportanceDigestion, immunity, possibly brainModerate
Feed itEat fibreStrong
HypeLarge, much unproven
169 studies28 answersupdated aug 2026
Evidence per claim
Fibre feeds your gut flora and helps long term
View evidence →Gut flora and mood or brain are linked
View evidence →A disturbed gut flora can weaken immunity
View evidence →Artificial sweeteners can affect the gut flora
View evidence →Practical use
For whom
Everyone; a varied, fibre-rich diet is the basis for a healthy gut flora.
Not for whom
Expensive microbiome tests and most probiotic pills add little for healthy people.
Usual dose
Eat varied and fibre-rich (vegetables, fruit, legumes, wholegrain); fermented food can help.
Key caveats
The science is still early; distrust firm claims and commercial tests.
What we know, and don't
Known
Fibre feeds the gut flora
A varied diet helps
Gut flora affects immunity and possibly brain
Not yet
What the ideal composition is
Whether probiotic pills add much
What a microbiome test means for you
Common misconceptions
"A microbiome test tells you what to eat."
Not shown. The science is not there yet; most tests are of little use.Moderate evidence
"Probiotic pills fix everything."
Incomplete. For healthy people the added value is limited; fibre does more.Moderate evidence
How Microbiome connects
Effects
Related news
A gut bacterium in centenarians shields the intestinal wallGut-derived TMAO raises atrial fibrillation riskGut bacteria composition correlates with biological age