Non-allergic food hypersensitivity
While a food allergy is an adverse reaction to food which involves the immune system, food intolerance can be described as an adverse reaction to food which does not trigger the immune system and is not life-threatening.
Food intolerance may result from:
- Enzymes deficiencies such as inadequate production of lactase, the enzyme breaking down lactose from dairy products, leading to lactose intolerance.
- Sensitivity to food additives from naturally occurring (e.g. caffeine) or added chemicals (e.g. sulphites) that produce drug-like effects.
- Other unknown causes.
Usually the symptoms of food intolerance are milder, occur after eating larger portions of the problematic food and take longer to appear compared to symptoms of food allergy.
Some of the symptoms of food intolerance and allergy are similar. However, if you are intolerant to a food, eating it may lead to discomfort, whereas when you eat a food you are truly allergic to, your body reaction may be severe and even life-threatening.
Lactose is a sugar present in dairy products. In the digestive system, lactose is broken down in the presence of the enzyme called lactase into smaller compounds which can be absorbed into the bloodstream by the small intestine.
Some people, as they get older, stop producing sufficient amount of lactase and become lactose intolerant.
If they consume a dairy product rich in lactose, the undigested sugar will move to the colon where it will be broken down by bacteria. During this process excess gas and liquid will be produced, leading to uncomfortable bloating and possibly diarrhoea.
Lactose intolerance affects around 70% of people worldwide. There is a wide variation between different areas, for example about 30% of Europeans are lactose intolerant, while in the Middle East the percentage is significantly higher (70%).
Lactose intolerance is sometimes confused with cow’s milk allergy by parents and patients.
Di Costanzo, M., Berni, Canani, R. (2018) Lactose Intolerance: Common Misunderstandings
Storhaug, L.C., Fosse, S.K, Fadnes, S.K. (2017) Country, regional, and global estimates for lactose malabsorption in adults: a systematic review and meta-analysis.
- J. L. Turnbull, H. N. Adams & D. A. Gorard (2015) Review article: the diagnosis and management of food allergy and food intolerances