Food intolerance


Drª Maria Alice is a consultant in General and Family Medicine, and is Director of Luzdoc International Medical Service in Praia da Luz, near Lagos.

Historically, a lack of acceptance that food intolerance exists has meant that many sufferers have failed to receive the help and support they require. Food intolerance can be the cause of many symptoms including fatigue, headaches, weight problems, bloating, sinus problems and depression to name but a few!

It is important to distinguish between having an allergy to something you eat and your body being intolerant to it!

Classical food allergy

This is the term used to describe an adverse reaction that can occur quite rapidly, often within minutes but generally within a maximum of two hours of consuming an offending food. A classic food allergy is quite rare affecting around two per cent of the population. Symptoms vary but are generally obvious and sometimes quite violent, for example, a rash or hives developing after eating strawberries or being violently sick after eating shellfish. In more serious but rare cases anaphylactic shock can occur where the airways can close due to swelling and if not treated immediately can, in extreme cases, result in death.  

Regardless of whether the reaction is mild or extreme the immune system is always involved, reacting to a particular food as if it isn’t safe. This is the body’s defence against foreign invaders. More commonly it is activated against things like harmful bacteria and viruses but in the case of a food allergy it is against specific foods.  

The specific kinds of antibodies produced during this type of a reaction are known as IgE antibodies. These are what a doctor will be looking for if he/she recommends a blood test. IgE antibodies have a long term memory. If you have an IgE immune response to a substance you will almost always have this type of reaction and therefore these foods should be permanently avoided especially when the reaction is severe, anaphylactic shock, for example.

Food intolerance

Food intolerance is quite different to food allergy, it is not life threatening although it can, and does, make the sufferer feel extremely unwell. It is estimated that up to 45 per cent of the population will suffer from food intolerance at some point in their life.

Symptoms or reactions are often delayed appearing up to 48 hours after the food is eaten, thus making it very difficult to identify the food that is causing the problem. The severity of the symptoms can also vary depending on how much and how often a particular food or food family is consumed.

Food intolerance occurs when the body is unable to deal with a certain type of foodstuff. This may be because the body does not produce enough of the particular chemical or enzyme that is needed for digestion of that food. Large macromolecules then enter the circulation stimulating an immune response. A different kind of antibody is produced to that seen in a food allergy reaction. This is known as the IgG antibody. Unlike the IgE antibody, this type of antibody has a short term memory – generally from three months to a year. In effect this means that once the offending food/s is/are removed from the diet for a period of up to three months or more the immune system effectively forgets that it once reacted to it and an IgG response is no longer activated. Thus, an elimination of the offending foods for a period of time followed by a gradual and controlled re-introduction process can be an effective way of treating the intolerance and consequently the symptoms that they cause. (To be continued next month)

Elizabeth Hartland has a Bachelor of Science Degree in Nutrition and a Diploma from the Institute for Optimum Nutrition. She has worked alongside a Harley Street Doctor and also worked with several GPs in the UK. She has been a manager in the Nutrition Department of a leading UK supplement company and has also run her own practice for over 20 years dealing with a wide range of health problems ranging from IBS to the menopause and arthritis. Her present position in the UK is with a Charity dealing specifically with those suffering from arthritis in all its many forms. Elizabeth has become a leading authority in helping those suffering with this debilitating condition. Elizabeth plans to move to Portugal in 2009 and will be available for consultation at Luzdoc.

Best health wishes,

Dr. Maria Alice

Drª Maria Alice can be contacted by calling (00351) 282 780 700 or by emailing [email protected]  or in confidence to [email protected]