Q.Prashant began vomiting after lunch at school. He was promptly taken to a nearby doctor, who diagnosed him with food intolerance. Outline three types of food intolerance. (1 × 3 = 3)

Food intolerance = a non-allergic, digestive-system reaction: the body cannot properly process a food (no immune involvement). Three types:

1. Enzymatic — a digestive enzyme is missing/deficient, e.g. lactose intolerance (lack of lactase → gas, cramps, diarrhoea after milk).
2. Pharmacological (chemical) — sensitivity to naturally occurring food chemicals acting like drugs, e.g. caffeine in coffee or tyramine in aged cheese → palpitations, headaches; dose-dependent. …

Concept understanding — intolerance is not allergy

Prashant's vomiting after lunch was diagnosed as food intolerance — a condition quite different from a food allergy. A food allergy involves the immune system and can be life-threatening; a food intolerance is a digestive-system response: the body simply cannot properly break down or handle a particular food or ingredient. It is far more common than allergy, and its typical symptoms — bloating, gas, cramps, diarrhoea, vomiting — match exactly what Prashant experienced.

The three types of food intolerance

1. Enzymatic food intolerance

The body lacks (or is deficient in) a specific enzyme needed to digest a food component. The classic example is lactose intolerance: without enough lactase, the milk sugar lactose stays undigested and ferments in the gut, producing cramps, gas and diarrhoea. This is a deficiency of digestion, not an immune attack.

2. Pharmacological (chemical) food intolerance

Some foods contain naturally occurring chemicals that act like drugs in sensitive people — for example caffeine in coffee or tyramine in aged cheese. In susceptible individuals these trigger headaches, palpitations or a racing heartbeat. The reaction is dose-dependent: a small amount may cause no trouble, while a larger quantity overwhelms the body's capacity to handle the chemical.

3. Idiosyncratic food intolerance …