Foods linked to intolerance

Unlike food allergies, there is no single cause of food intolerance. The symptoms experienced after eating a particular food are probably caused by a number of different mechanisms, most of which are poorly understood.

Many foods can cause a food intolerance. But the most common in the UK are:

• milk
• lactose
• gluten
• wheat
• food additives
• naturally occurring compounds in foods

Lactose intolerance, which affects around 5% of people in the UK, is caused by a shortage of the enzyme lactase, which is needed to break down the sugar lactose found in cow milk. This prevents the sugar from being absorbed from the gut.

Because lactose is present in milk, people often assume they have lactose intolerance when they may be intolerant to some of the proteins present in milk instead. This is also different from a milk allergy.

Gluten intolerance, or coeliac disease, is thought to affect as many as one in three hundred people in the UK. Coeliac disease is an autoimmune disease triggered by eating gluten, a protein present in cereals such as rye, wheat and barley. In some people with coeliac disease, symptoms are also triggered by eating oats, which also contains a protein similar to gluten.

People may mistake an intolerance to wheat with an intolerance to gluten as they are often found in the same foods, which is why it is important to have it checked out by your GP or a registered dietician.

Some people are sensitive to naturally occurring compounds found in foods. These include caffeine in coffee and amines in some cheeses, which can cause headaches.

Only a small number of people are affected by food additives. Those most commonly linked to food intolerance include an artificial colourant called tartrazine (E102) and sulphites, metabisulphites and benzoates, which are used as preservatives.

Certain foods can also trigger or exacerbate pre-existing health conditions such as asthma, irritable bowel syndrome, Crohn’s disease and migraines.

It is important to consult with your GP before excluding foods from your diet. This is particularly important when dealing with children, or if you already have a health condition.

This article was published on Tue 25 August 2009