Gut Health — H. pylori, Stool Tests & Your Second Brain

The gastrointestinal tract is increasingly recognised as a central organ in systemic health. It houses:

• **The gut microbiome:** 100 trillion bacteria, fungi, and viruses that influence metabolism, immunity, and even mood

• **The enteric nervous system:** 500 million neurons lining the gut — called the 'second brain' because it operates independently and communicates bidirectionally with the brain via the vagus nerve

• **70% of the immune system:** Gut-associated lymphoid tissue (GALT) is the body's largest immune organ

Helicobacter pylori: is a spiral bacterium that colonises the stomach lining. It is spread through contaminated water and food — and India's infection rate of 60–70% is among the world's highest.

Most carriers are asymptomatic.: But H. pylori causes:

• Gastritis (chronic stomach inflammation)

• Peptic ulcers (stomach or duodenal)

• Increased risk of gastric cancer (classified Group 1 carcinogen by WHO)

• Iron deficiency anaemia (by interfering with iron absorption)

H. pylori detection tests::

Stool Antigen Test (SAT):: Non-invasive, highly accurate. Detects H. pylori antigens in stool. Preferred first-line test. Also used to confirm eradication after treatment.

H. pylori IgG antibody (blood):: Detects past exposure but cannot distinguish active from resolved infection. Useful for population screening.

Urea Breath Test (UBT):: H. pylori produces urease, which breaks down urea into CO₂. Patient drinks labelled urea and exhales. Very accurate for detecting active infection. Preferred over serology.

Endoscopic biopsy (CLO test):: Gold standard — tissue from the stomach directly tested during upper GI endoscopy.

Stool Routine and Microscopy (Stool R/E):: Detects:

• Parasites and their ova (Giardia, Entamoeba, Ascaris, hookworm)

• Occult blood (hidden bleeding from stomach or colon)

• Fat globules (malabsorption)

• Red blood cells and pus cells (dysentery, colitis)

Faecal Occult Blood Test (FOBT):: Detects microscopic blood in stool — an early warning for colorectal cancer, polyps, or GI bleeding. Recommended annually for adults over 45 as colorectal cancer screening. A positive FOBT requires colonoscopy for evaluation.

Calprotectin (Faecal):: A protein released by neutrophils in the gut lining during inflammation. Elevated calprotectin strongly suggests Inflammatory Bowel Disease (IBD — Crohn's or Ulcerative Colitis), distinguishing it from irritable bowel syndrome (IBS). Normal: < 50 µg/g stool.

Stool Culture:: Grows bacteria from stool to identify pathogens causing food poisoning or dysentery (Salmonella, Shigella, Campylobacter, E. coli, Vibrio).

IBS:: Functional disorder — no structural or inflammatory damage to the gut. Normal colonoscopy, normal calprotectin, normal CRP. Diagnosis by Rome IV criteria (symptoms-based).

IBD (Crohn's Disease / Ulcerative Colitis):: Genuine chronic inflammation of the gut wall, confirmed by elevated calprotectin, raised CRP and ESR, and colonoscopy with biopsy showing characteristic changes.

How to differentiate (blood + stool tests)::

• Calprotectin < 50: IBS likely

• Calprotectin > 200: IBD very likely — colonoscopy needed

• CRP, ESR: Usually normal in IBS; elevated in active IBD

• CBC: Anaemia common in IBD from blood loss and inflammation; rare in IBS

• Anyone with recurring abdominal pain, bloating, or altered bowel habits (IBS vs IBD distinction)

• Unexplained iron deficiency anaemia (H. pylori + FOBT)

• All adults over 45: Annual FOBT for colorectal cancer screening

• After travel to high-risk areas (stool microscopy for parasites)

• Unexplained weight loss with GI symptoms

• Known dyspepsia or recurrent peptic ulcer (H. pylori testing mandatory before long-term PPI use)

• Anyone wanting to understand their gut health baseline