GERD (Gastro-Oesophageal Reflux Disease) affects approximately 20% of adults worldwide — and its causes go far deeper than simply eating spicy food. Genetics, gut bacteria, and modern lifestyle all interact to create the burning mystery of chronic acid reflux.
What is GERD?
GERD occurs when stomach acid repeatedly flows back into the oesophagus, irritating its lining. Unlike occasional heartburn, GERD is a chronic condition that can lead to serious complications including oesophagitis, Barrett’s oesophagus, and oesophageal cancer if left untreated.
Common Symptoms
- Persistent heartburn (burning sensation in the chest)
- Regurgitation of food or sour liquid
- Difficulty swallowing (dysphagia)
- Chronic cough, especially at night
- Hoarseness or sore throat
- Feeling of a lump in the throat
- Disrupted sleep
The Genetic Component of GERD
Twin studies suggest that genetics accounts for approximately 30–43% of GERD susceptibility. Key genetic factors include:
- Lower Oesophageal Sphincter (LES) tone: Genetic variants influence the strength and function of the LES — the valve that prevents acid from flowing back into the oesophagus.
- Gastric acid secretion genes: Variants in genes governing proton pump activity influence how much acid your stomach produces.
- Obesity-related genes: Obesity is a major GERD risk factor, and genetic predisposition to weight gain indirectly increases GERD risk.
The Gut Microbiome Connection
Emerging research links gut dysbiosis (an imbalanced microbiome) to GERD. An overgrowth of certain bacteria in the small intestine (SIBO) can increase intra-abdominal pressure and promote acid reflux. Conversely, a diverse, healthy microbiome supports proper digestive motility and reduces reflux episodes.
Lifestyle and Dietary Management
- Avoid trigger foods: Fatty foods, chocolate, caffeine, alcohol, citrus, tomatoes, and spicy foods commonly worsen GERD.
- Eat smaller, more frequent meals to reduce gastric pressure.
- Don’t lie down within 3 hours of eating.
- Elevate the head of your bed by 15–20cm.
- Maintain a healthy weight — even modest weight loss significantly reduces GERD symptoms.
- Quit smoking — nicotine relaxes the LES.
Medical Treatment
- Proton Pump Inhibitors (PPIs): The most commonly prescribed GERD medications. Your CYP2C19 gene variant determines how effectively you metabolise PPIs — pharmacogenomic testing can identify the right PPI and dose for you.
- H2 Blockers: Reduce acid production with fewer side effects than PPIs for mild GERD.
- Antacids: Provide rapid but short-term relief.
- Surgery (Fundoplication): For severe, medication-resistant GERD.
Conclusion
GERD is a complex condition with genetic, microbial, and lifestyle roots. Understanding your genetic predisposition to acid reflux — and your microbiome’s role in digestive health — allows for a more targeted, personalised approach to management.
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