Adverse reaction to certain foods, although the conventional view is that true gastrointestinal allergy is rare.
Causes of Gastrointestinal allergy
It is a matter of common experience that certain foods make other conditions worse, for example eczema, asthma and migraine (see Headaches and migraine). Beyond that, the subject is bedevilled by lack of agreement as to what else constitutes a reaction and the possible mechanisms whereby the food alleged to be responsible has that effect.
Certain people clearly experience a true allergic reaction; others have more of an intolerance of certain foods. Acute gastroenteritis with diarrhoea leaves the lining of the intestine unable to handle the absorption of milk for a few days and the resulting persistent diarrhoea can be misinterpreted as allergy.
Coeliac disease is a true allergic reaction to gluten in the diet. Allergy to peanuts has for unknown reasons become more common in recent years. Other substances identified as possible causes of gastrointestinal allergy are tyramine in cheese, tartrazine (a food additive), egg protein and histamine in strawberries. The widespread concern about E numbers has not been scientifically substantiated.
Symptoms of Gastrointestinal allergy
There may be a true allergic reaction: within minutes there is a blotchy skin rash, tingling in the mouth, swelling of the lips and throat and wheezing. At its most severe there may be collapse through a fall in blood pressure, called anaphylaxis.
Food intolerance would be suspected by the appearance within hours or days of diarrhoea, bloating, or a worsening of asthma or of eczema. The diagnosis is supported by showing regular and repeated reactions to the foods in question. Individuals can be tested by exposure to dilute samples of the foods to which they might be intolerant.
A child who is suspected of cow’s milk or lactose intolerance with accompanying poor growth and diarrhoea should show catch-up growth and loss of bowel symptoms when a substitute is given. Lactose intolerance can also happen in adults, causing diarrhoea and flatulence.
There is no scientifically proven link between the many other symptoms, such as headaches and behavioural disturbances, that people complain of and true sensitivity to certain foods. For example, in double-blind trials individuals have unknowingly had foods they say they are allergic to, yet they have not shown the expected reaction.
Treatment of Gastrointestinal allergy
Where there is a definite association with a particular food, avoid the offending substance. The more severe the reaction the more scrupulously this must be done, for example people with an acute anaphylactic reaction to eggs or nuts must be obsessive about avoiding them. Such people should wear a bracelet with medical details. There are self-injection devices containing adrenaline for immediate treatment. Lesser degrees of allergy are treated with antihistamine tablets or steroids for stronger reactions.
There is little orthodox medical support for diets that exclude a wide range of common foods on the basis that they cause arthritis, malaise, tiredness, hyperactivity and so on.
What is an exclusion diet?
It is a very simple diet with just a few foods. The idea is to see whether symptoms disappear, then to introduce a single food from fortnight to fortnight until one provokes the symptoms.
What is wrong with this?
Few people manage to do it properly for the many weeks that are necessary. The interpretation is difficult as the symptoms are often vague and not easily objectively assessed. Extreme exclusion diets may not be nutritionally complete if followed for long periods.
Are other tests available?
Blood tests may show abnormal reactions, but their interpretation is controversial. Scientific studies of hair analysis and many other complementary and alternative procedures do not support the faith some therapists have in them.
A registered homeopath could greatly reduce, or even eradicate, your food sensitivity. Nutritional therapy can help you identify food intolerance; if you have multiple allergies they could be linked to toxic overload and you will need to undertake work to improve your bowel, liver and digestive system. Hypnotherapy can be used in conjunction with a desensitizing programme. Ayurveda treats gastrointestinal allergy through detoxification, and oral preparations and marma therapy are also important.