Bacteria · Species

Faecalibacterium prausnitzii

Beneficial A dominant butyrate producer with strong anti-inflammatory effects — one of the most consistently health-associated bacteria in the gut.

Associated with these conditions

Inflammatory bowel disease (IBD) Reduced

Depletion of this anti-inflammatory butyrate producer is among the most consistently replicated IBD findings.

Well-replicated

Irritable bowel syndrome (IBS) Mixed

Reported both reduced and unchanged depending on cohort and IBS subtype.

Disputed / mixed studies conflict

Type 2 diabetes Reduced

Butyrate producers decline — but several studies were confounded by metformin, not diabetes itself.

Moderate evidence studies conflict

Fatty liver disease (MASLD) Reduced

Loss of this anti-inflammatory species tracks liver-fat and fibrosis severity.

Moderate evidence

Colorectal cancer Reduced

Protective butyrate producers tend to be depleted as tumors develop.

Moderate evidence

Depression & anxiety Reduced

Lower abundance correlates with depression and reduced quality-of-life scores in population studies.

Moderate evidence

Psoriasis Reduced

Depletion of this anti-inflammatory species is reported in psoriasis cohorts.

Preliminary

Asthma Reduced

Part of the protective FLVR taxa whose early depletion tracks asthma risk.

Moderate evidence

Crohn's disease(CD) Reduced

Reported in HMDAD (1 cited study).

Moderate evidence

Liver cirrhosis Reduced

Reported in HMDAD (1 cited study).

Moderate evidence

Multiple sclerosis Associated with

Reported in Disbiome.

Preliminary

Parkinson’s disease Associated with

Reported in Disbiome.

Preliminary

Infective colitis Associated with

Reported in Disbiome.

Preliminary

Type 1 diabetes Associated with

Reported in Disbiome.

Preliminary

Atopy Associated with

Reported in Disbiome.

Preliminary

Familial adenomatous polyposis Associated with

Reported in Disbiome.

Preliminary

Celiac Disease, Coaliac disease Associated with

Reported in Disbiome.

Preliminary

Obesity Associated with

Reported in Disbiome.

Preliminary

Hepatitis B Associated with

Reported in Disbiome.

Preliminary

Eczema (atopic dermatitis) Associated with

Reported in Disbiome.

Preliminary

Cystic fibrosis Associated with

Reported in Disbiome.

Preliminary

Pervasive developmental disorder NOS Associated with

Reported in Disbiome.

Preliminary

Autism spectrum (ASD) Associated with

Reported in Disbiome.

Preliminary

Spondyloarthritis Associated with

Reported in Disbiome.

Preliminary

Inactive Crohn's Disease Associated with

Reported in Disbiome.

Preliminary

Chronic kidney disease Associated with

Reported in Disbiome.

Preliminary

Inflammatory Bowel Disease Associated with

Reported in Disbiome.

Preliminary

Pancreatitis Associated with

Reported in Disbiome.

Preliminary

Opisthorchis felineus infection Associated with

Reported in Disbiome.

Preliminary

Cardiovascular disease Associated with

Reported in Disbiome.

Preliminary

Liver transplant Associated with

Reported in Disbiome.

Preliminary

Pulmonary tubercolosis Associated with

Reported in Disbiome.

Preliminary

Cirrhosis Associated with

Reported in Disbiome.

Preliminary

Non-alcoholic fatty liver disease Associated with

Reported in Disbiome.

Preliminary

Heart failure Associated with

Reported in Disbiome.

Preliminary

Idiopathic nephrotic syndrome Associated with

Reported in Disbiome.

Preliminary

Hyperlipidemia Associated with

Reported in Disbiome.

Preliminary

Primary sclerosing cholangitis Associated with

Reported in Disbiome.

Preliminary

Primary sclerosing cholangitis-IBD Associated with

Reported in Disbiome.

Preliminary

Myasthenia gravis Associated with

Reported in Disbiome.

Preliminary

Keratitis Associated with

Reported in Disbiome.

Preliminary

Systemic lupus erythematosus Associated with

Reported in Disbiome.

Preliminary

Autism spectrum disorders Associated with

Reported in Disbiome.

Preliminary

Frailty Associated with

Reported in Disbiome.

Preliminary

Metabolic syndrome Associated with

Reported in Disbiome.

Preliminary

Juvenile idiopathic arthritis Associated with

Reported in Disbiome.

Preliminary

Allergic asthma Associated with

Reported in Disbiome.

Preliminary

Fibromyalgia Associated with

Reported in Disbiome.

Preliminary

Colon polyps Associated with

Reported in Disbiome.

Preliminary

Cholestasis Associated with

Reported in Disbiome.

Preliminary

Aerobic vaginitis Associated with

Reported in Disbiome.

Preliminary

Migraine Associated with

Reported in Disbiome.

Preliminary

Attention Deficit Hyperactivity Disorder Associated with

Reported in Disbiome.

Preliminary

Human end-stage renal disease Associated with

Reported in Disbiome.

Preliminary

Clostridium difficile infection Associated with

Reported in Disbiome.

Preliminary

Lung cancer Associated with

Reported in Disbiome.

Preliminary

Normal weight obesity Associated with

Reported in Disbiome.

Preliminary

Fatigue Associated with

Reported in Disbiome.

Preliminary

Covid-19 Associated with

Reported in Disbiome.

Preliminary

Crohn Disease Associated with

Reported in Peryton.

Preliminary

Celiac disease Associated with

Reported in Peryton.

Preliminary

Colorectal Neoplasms Associated with

Reported in Peryton.

Preliminary

Parkinson Disease Associated with

Reported in Peryton.

Preliminary

Breast Neoplasms Associated with

Reported in Peryton.

Preliminary

Prostatic Neoplasms Associated with

Reported in Peryton.

Preliminary

Irritable Bowel Syndrome Associated with

Reported in Peryton.

Preliminary

Esophageal Neoplasms Associated with

Reported in Peryton.

Preliminary

Stomach Neoplasms Associated with

Reported in Peryton.

Preliminary

Lung Neoplasms Associated with

Reported in Peryton.

Preliminary

What shifts it

Dietary fibre Raises it

Nutrient

Moderate evidence Well-established

Helps make

Short-chain fatty acidsneurotransmitter

The dominant chemical channel from gut to brain. Made when fibre-fermenters break down fibre, SCFAs feed the gut lining, calm microglia, tune the blood–brain barrier, and signal along the vagus nerve. Not a neurotransmitter in the textbook sense — but arguably the microbiome’s most important neuroactive output.

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