Intolerance to food

What is it?

Food intolerance can result in a range of symptoms and is not restricted to the gastrointestinal tract. Some people experience itchiness, numbness or swelling of the mouth or throat, heartburn, stomach ache, bloating, wind, constipation or diarrhoea. Skin symptoms can include itchiness and burning sensation. Other symptoms like headaches, fatigue or muscle/joint aches can also occur. Food intolerance does not involve the immune system and it does not cause anaphylaxis. Skin or blood tests cannot help to find the cause. For some substances breath testing is available (lactose, fructose).

What causes it?

The exact mechanism by which some food intolerances develop is not always clear. Intolerance is often related to the amount of the food eaten. Small amounts can sometimes be tolerated or the food can be tolerated if ingested only a few times a week.

Metabolic cause: One example is the intolerance to lactose, the sugar in dairy. Intolerance is caused by a lack of or low effectiveness of the enzyme lactase. Not all of the lactose can be absorbed and reaches the large intestine. The bacteria which are present in the large intestine digest the lactose and produce a lot of gas which can cause wind and pain. The lactose also causes influx of water into the intestine leading to diarrhoea.

Pharmacological cause: Intolerance to food components, such as caffeine from tea or coffee, flavour enhancers or naturally occurring food chemicals like salicylates or amines. Unclear mechanisms, such as reactions to sulphite preservatives, or toxic reactions are considered food intolerances.

Dietetic treatment:

The treatment would either be restricting amounts or frequency of the foods in the diet. In the case of lactose intolerance yoghurt and cheese are sometimes tolerated even if they still contain lactose. There are lactose free dairy products available which are well tolerated. Food ingredients need to be checked on the nutrition information panel of the food. People sensitive to naturally occuring food chemicals need to restrict amounts of not well tolerated foods or replace them with similar but low chemical containing foods. Sulphites are listed on nutrition information labels (eg. in dried fruits or wine) and possibly need to be avoided. Sometimes it is difficult to pinpoint the food that causes a reaction. As we are ingesting a range of foods and drinks it is possible to find out through an elimination diet and later challenge of the suspected food/s.