Food intolerance

Food intolerance is when your body has difficulty digesting a particular food and reacts with digestive symptoms. It is different from a food allergy — a food allergy involves the immune system and can cause sudden, severe reactions. Food intolerance does not involve the immune system and is not life-threatening, but it can make you feel very unwell.

Common food intolerances in India

• Lactose intolerance — difficulty digesting milk sugar (lactose). Very common in Indian adults; symptoms include bloating, gas, and diarrhoea after milk or dairy.
• Wheat / gluten intolerance (separate from coeliac disease) — bloating and gut symptoms after wheat
• Fructose intolerance — reaction to fruit sugars
• Histamine intolerance — reaction to foods high in histamine (aged cheese, fermented foods, wine)
• Food additives — some people react to MSG, sulphites, or artificial colours
• Coeliac disease (separate condition) — an autoimmune reaction to gluten, not a simple intolerance

Symptoms

Usually digestive, appearing hours to a day after eating:

• Bloating, gas
• Stomach pain
• Diarrhoea
• Nausea
• Sometimes headache, skin problems, or a run-down feeling

Figuring out which food

Keep a food-and-symptom diary for a few weeks, then work with a doctor or dietitian to try an elimination diet — remove the suspected food for 2-4 weeks, then reintroduce it and watch for symptoms. Avoid expensive commercial "food intolerance tests" that promise to identify dozens of foods from a single blood or hair sample — these are not scientifically reliable.

Management

• Limit or avoid the food you don't tolerate
• For lactose intolerance — smaller amounts are often OK; lactose-free milk, curd/dahi (usually well-tolerated due to lower lactose), or lactase-enzyme supplements help
• A dietitian can help you plan a balanced diet that avoids trigger foods without missing nutrients
• See a doctor if symptoms are severe, you lose weight, or there's blood in stools — these suggest a problem beyond intolerance