Adverse reactions to foods, and autism
Autism Management Limited – #5 in a series of informative papers.
Dr Edward Danczak
Food reactions can in general be classified as immune in origin such as an allergy, and of non immune origin which may be called intolerance.
Food, since it is taken by everyone, features high in the index of suspicion when looking at autistic behaviour, with widespread concern at the possibility that intake of dairy and wheat products may be a triggering factor for abnormal behavioural activity.
A recent UK Government report comments that up to 30% of the UK population believes that they have a food allergy or some kind of adverse reaction to foods. This figure can be clarified by using objective measurements, which reveal a much lower figure of around 1.8%. (1)
The most common reaction is to natural food and not to synthetic additives or contaminants, the prevalence of which is around 0.03%.
Children in general have much higher reactivity than adults, with up to 8% suffering adverse responses. In general 90% of food reactions in children are caused by one of the following: cows milk, chickens eggs, wheat, peanuts, tree nuts (hazel,brazil,walnuts) and soya protein.
It is not surprising that wheat milk and eggs have the highest incidence of reaction since they are the most common ingredients in early years diet.
Wheat can cause reactions in autistic children through a number of different routes.
Direct immune response with a classic eczema rash, and sometimes the onset of asthma in susceptible individuals. There may also be vomiting, colic, and diarrhoea. Symptoms may start within a matter of minutes and may last for many days before stability returns. This may be associated with a deterioration in concentration, communication and overall functional activity. Indeed behavioural changes may be the only indicator of reactivity.
There are at least three other routes to intolerance.
Inadequate breakdown of wheat peptides (short chains of amino acids) contained in gluten, part of wheat, due to intestinal wall depletion of peptidases, (enzymes) which break down the peptides into non toxic fragments. This failure is shared in some milk intolerances. These peptidases are Zinc dependent, and would be expected to be reduced in population when there is bowel wall damage. This breakdown failure leads to absorption of glutenomorph peptides which look and behave like enkephalins, naturally produced morphine like mediators. Measurement of these urinary peptides provides one route of assessment of inappropriate absorption (2) (4) Symptoms may include lack of concentration, introspection, intoxicated behaviour, and repetitive movement. Self injury is not uncommon.
Another well recognised route is gluten intolerance causing coeliac disease. This is a recognised cause of malabsorption, detectable on intestinal biopsy, by blood test, and by the gold standard of reactivity on exposure to gluten containing food. All enterologists are familiar with this process. Foul smelling difficult to clear stools with poor weight gain, bloating, gas, anaemia and failure to thrive are commonly seen.
Gluten, which is quite a complex structure, contains a substrate called gliaden. This contains a protein called a lectin, which is toxic, not broken down by digestive enzymes, and which can cause unexpected clinical illness ranging from diarrhoea to intestinal damage, to various types of arthritis. The wheat lectin is classified by its ability to bind glucose. It shares this with a lectin contained in potato. This may explain why some children do not respond well to wheat withdrawal, but then respond well to potato exclusion. It may be that the glucose receptor on the lectin is the common reactive trigger. It also offers the possibility of using accurately targeted medication to block the lectin activity, and allow a child to take prophylactic medication to block sensitivity reactions. (3)
If you think that wheat intolerance could be contributing to your child’s condition, before planning to exclude wheat as a dietary constituent, discuss this with your physician. Inadvertent malnutrition is common in autistic children through inappropriate dietary intervention.
Dr Edward Danczak
1) firstname.lastname@example.org (COT Secretariat, Food Standards Agency)
2) Reichelt KL., Knivsberg A-M., Nodland M.,Lind G.,Nature and Consequences of Hyperpeptiduria and Bovine caseinomorphins found in autistic syndromes. Development Brain Dysfunction 1994;7:71-85
3) Van Damme E.,Peumans WJ., Pusztai A., Bardocz S.,Handbook of Plant Lectins, Properties and Biomedical Applications. John Wiley 1998 ISBN 0-471-96445-X
4) Shattock P.,Kennedy A.,RowellF.,BerneyT.,Role of Neuropeptides in Autism and their relationships with Classical Neurotransmitters, Brain Dysfunction, 1990 3:328-345
Copyright (c) 2000 [Autism Management Limited]. All rights reserved.
Revised: September 07, 2000 .