Bacteria · Genus

Bifidobacterium

Beneficial Beneficial, fibre-loving bacteria and a common probiotic target; abundant in breastfed infants and broadly protective.

Associated with these conditions

Irritable bowel syndrome (IBS) Reduced

Commonly lower in IBS and a frequent probiotic target, though effect sizes vary widely.

Moderate evidence

Celiac disease Reduced

Lower Bifidobacterium is repeatedly reported and is a probiotic target under study.

Moderate evidence

Necrotizing enterocolitis Reduced

Scarcity of protective Bifidobacterium precedes disease; probiotics reduce NEC risk in preterm infants.

Moderate evidence

Eczema (atopic dermatitis) Reduced

Low infant Bifidobacterium repeatedly precedes eczema — central to the ‘old friends’ hypothesis.

Moderate evidence

Food allergy Reduced

Depleted protective taxa (Bifidobacterium and Clostridia) accompany allergic sensitization.

Preliminary

Diarrhea Irritable bowel syndrome(IBS) Reduced

Reported in HMDAD (1 cited study).

Moderate evidence

Rheumatoid arthrits Reduced

Reported in HMDAD (1 cited study).

Moderate evidence

Type 1 diabetes Elevated

Reported in Disbiome, HMDAD (1 cited study).

Moderate evidence

Irritable Bowel Syndrome Associated with

Reported in Disbiome, Peryton.

Moderate evidence

Cirrhosis Associated with

Reported in Disbiome.

Preliminary

Inflammatory bowel disease (IBD) Associated with

Reported in Disbiome, Peryton.

Moderate evidence

Autism spectrum (ASD) Associated with

Reported in Disbiome.

Preliminary

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

Colorectal cancer Associated with

Reported in Disbiome.

Preliminary

Obesity Associated with

Reported in Disbiome.

Preliminary

Celiac Disease, Coaliac disease Associated with

Reported in Disbiome.

Preliminary

Systemic sclerosis Associated with

Reported in Disbiome.

Preliminary

Behcet's Disease Associated with

Reported in Disbiome.

Preliminary

Cystic fibrosis Associated with

Reported in Disbiome.

Preliminary

Autoimmune hepatitis Associated with

Reported in Disbiome.

Preliminary

Hepatitis B Associated with

Reported in Disbiome.

Preliminary

Chronic Obstructive Pulmonary Disease Associated with

Reported in Disbiome.

Preliminary

Interstitial cystitis Associated with

Reported in Disbiome.

Preliminary

High blood pressure Associated with

Reported in Disbiome.

Preliminary

Viral Diarrhea Associated with

Reported in Disbiome.

Preliminary

Aggressive periodontitis Associated with

Reported in Disbiome.

Preliminary

Type 2 diabetes Associated with

Reported in Disbiome.

Preliminary

Spondyloarthritis Associated with

Reported in Disbiome.

Preliminary

Rett Syndrome Associated with

Reported in Disbiome.

Preliminary

Non alcoholic steatohepatitis Associated with

Reported in Disbiome.

Preliminary

Hepatic encephalopathy Associated with

Reported in Disbiome.

Preliminary

Hashimoto's thyroiditis Associated with

Reported in Disbiome.

Preliminary

Ankylosing spondylitis Associated with

Reported in Disbiome.

Preliminary

Chronic kidney disease Associated with

Reported in Disbiome.

Preliminary

Alzheimer’s disease Associated with

Reported in Disbiome.

Preliminary

Liver transplant Associated with

Reported in Disbiome.

Preliminary

Hyperthyroidism Associated with

Reported in Disbiome.

Preliminary

Alcoholic hepatitis Associated with

Reported in Disbiome.

Preliminary

Allergic asthma Associated with

Reported in Disbiome.

Preliminary

Pancreatic cancer Associated with

Reported in Disbiome.

Preliminary

Protracted bacterial bronchitis Associated with

Reported in Disbiome.

Preliminary

Atopic wheeze Associated with

Reported in Disbiome.

Preliminary

Infantile eczema Associated with

Reported in Disbiome.

Preliminary

Major depressive disorder Associated with

Reported in Disbiome.

Preliminary

Hepatocellular cancer Associated with

Reported in Disbiome.

Preliminary

Rectal Carcinoma Associated with

Reported in Disbiome.

Preliminary

Arsenic exposure Associated with

Reported in Disbiome.

Preliminary

Lung cancer Associated with

Reported in Disbiome.

Preliminary

Graves' disease Associated with

Reported in Disbiome.

Preliminary

Sjögren Syndrome Associated with

Reported in Disbiome.

Preliminary

Bronchiolitis Associated with

Reported in Disbiome.

Preliminary

Asthma Associated with

Reported in Disbiome.

Preliminary

Hand, foot and mouth disease Associated with

Reported in Disbiome.

Preliminary

Infant colic Associated with

Reported in Disbiome.

Preliminary

Obstructive sleep apnea-hypopnea syndrome Associated with

Reported in Disbiome.

Preliminary

Systemic lupus erythematosus Associated with

Reported in Disbiome.

Preliminary

Silicosis Associated with

Reported in Disbiome.

Preliminary

Inflammatory Bowel Disease Associated with

Reported in Disbiome.

Preliminary

Primary sclerosing cholangitis-IBD Associated with

Reported in Disbiome.

Preliminary

Cholestasis Associated with

Reported in Disbiome.

Preliminary

Smoking Associated with

Reported in Disbiome.

Preliminary

Glycogen storage disease Associated with

Reported in Disbiome.

Preliminary

Gastric carcinoma Associated with

Reported in Disbiome.

Preliminary

Clostridium difficile infection Associated with

Reported in Disbiome.

Preliminary

Metabolic syndrome Associated with

Reported in Disbiome.

Preliminary

Psoriasis Associated with

Reported in Disbiome.

Preliminary

Acne Associated with

Reported in Disbiome.

Preliminary

Bladder cancer Associated with

Reported in Disbiome.

Preliminary

Diarrhea Associated with

Reported in Disbiome, Peryton.

Moderate evidence

HIV infection Associated with

Reported in Disbiome.

Preliminary

Atrial fibrillation Associated with

Reported in Disbiome.

Preliminary

Fibromyalgia Associated with

Reported in Disbiome.

Preliminary

Attention Deficit Hyperactivity Disorder Associated with

Reported in Disbiome.

Preliminary

Biliary atresia Associated with

Reported in Disbiome.

Preliminary

Rheumatoid arthritis Associated with

Reported in Disbiome.

Preliminary

Pancreatitis Associated with

Reported in Disbiome.

Preliminary

Idiopathic focal epilepsy Associated with

Reported in Disbiome.

Preliminary

Acute lymphoblastic leukemia Associated with

Reported in Disbiome.

Preliminary

Stevens-Johnson syndrome Associated with

Reported in Disbiome.

Preliminary

Autism spectrum disorders Associated with

Reported in Disbiome.

Preliminary

Chronic urticaria Associated with

Reported in Disbiome.

Preliminary

Alcoholism Associated with

Reported in Disbiome.

Preliminary

Human end-stage renal disease Associated with

Reported in Disbiome.

Preliminary

Crohn Disease Associated with

Reported in Peryton.

Preliminary

Colorectal Neoplasms Associated with

Reported in Peryton.

Preliminary

Parkinson Disease Associated with

Reported in Peryton.

Preliminary

Alzheimer Disease Associated with

Reported in Peryton.

Preliminary

Stomach Neoplasms Associated with

Reported in Peryton.

Preliminary

Mouth Neoplasms Associated with

Reported in Peryton.

Preliminary

Pancreatic Neoplasms Associated with

Reported in Peryton.

Preliminary

Chronic constipation Associated with

Reported in Peryton.

Preliminary

Liver Neoplasms Associated with

Reported in Peryton.

Preliminary

Rectal Neoplasms Associated with

Reported in Peryton.

Preliminary

Lung Neoplasms Associated with

Reported in Peryton.

Preliminary

Esophageal Neoplasms Associated with

Reported in Peryton.

Preliminary

What shifts it

Dietary fibre Raises it

Nutrient

Moderate evidence Well-established

Iron Lowers it

Nutrient

Moderate evidence Well-established

Chronic stress Lowers it

Mind & stress

Moderate evidence Well-established

Antibiotics Lowers it

Medication

Well-replicated Well-established

Helps make

GABAneurotransmitter

The main inhibitory (calming) neurotransmitter — the same target as many anti-anxiety drugs. Certain bacteria make it via glutamate decarboxylase; Bifidobacterium adolescentis is a model producer, and its abundance correlates inversely with depression and anxiety.

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