Food Intolerance

People who are sensitive to a particular food often assume they are 'allergic' to that food. This often the case, but an allergic reaction is triggered by the body's immune system and there are other adverse reactions to food that do not involve the immune system. The term 'food intolerance' is used to describe this type of abnormal reaction. The symptoms experienced (rashes, headaches or feeling bloated) are similar to allergic reactions, but the mechanism is different.

The table shows some examples of food intolerance.

Examples of Food Intolerance
Intolerance Comments
Lactose intolerance (alactasia) Common form of intolerance to cow's milk found in people who lack the enzyme lactase and consumption of dairy products makes them sick. This means they cannot digest the milk sugar lactose
Naturally occurring (biogenic) amines The amines histamine and tyramine can reach high levels in cheese, some wines, tuna and mackerel. If these foods are eaten, they can cause adverse reactions in susceptible individuals
Food additives Certain colours, preservatives and anti-oxidants, can also cause adverse reactions in susceptible individuals . If a person has bad reaction to a food additive it is thought that this is because they already have some form of a problem and this is made worse by the additive rather than caused by it
Sulfites In high concentrations can affect a small sub-group of people with severe asthma. Steroid-dependent asthmatics are most at risk and anaphalactic type reactions, e.g. severe breathing problems, are reported to have occured on occasions
Benzoates Can affect asthmatics and aggravate dermatitis (inflamed skin)
Azo dyes These have been linked to a variety of symptoms, e.g. skin rash, asthma and dermatitis. It is well established that tartrazine and other azo dyes can occasionally provoke skin rash. Tartrazine is also known to have affected patients with dermatitis
Chinese Restaurant Syndrome
Chinese foods can contain a lot of the flavour enhancer monosodium glutamate (MSG). It has been linked with people who suffer reactions after eating Chinese meals. However, tests have not shown a link with MSG and the problems are most likely caused by other compounds such as naturally-occuring histamine in the ingredients

Colourings and hyperactivity

There have been lots of studies investigating a possible link between colours and childhood hyperactivity or attention deficit syndrome. The results have not given a clear-cut answer. Behaviour in children is a very complex area and many different factors could be responsible for any problems.

Evidence suggests that the person's whole diet can have an effect but it has not been narrowed down to particular foods or additives as a cause of the problems.

Use the links on the side to take a more detailed look at the issue of hyperactivity.

How common is food intolerance? Find out here