Food Intolerance: Pharmacological Aspects



Dr. Ronald Finn, M.D. FRCP
Consultant Physician, Royal Liverpool Hospital, Liverpool, England


Diet is the most important environmental factor affecting man. This was recognized from very early times and manipulation of the diet was a major weapon in treating disease. Indeed before the introduction of potent modern drugs, diet was the only effective therapeutic method available to physicians, hence the importance given to fasting in religious practice, because the functions of the physician and priest were combined. The availability of modern drugs led to a decline in interest in diet, but this trend is now being reversed, and modern practice should be to combine diet and drug therapy in the management and prevention of disease.


The purpose of this presentation is to present a classification of food intolerance and to emphasize the importance of recognizing pharmacological reactions in clinical practice.


Psychological Reactions include anorexia nervosa and bulimia and are readily distinguished from organic reactions.
Enzyme Defects include lactose intolerance and avoidance of the relevant food is clinically effective.


Toxic Reactions The use of synthetic chemical additives such as preservatives, colouring and tasting agents, can cause symptoms in sensitive subjects, and the use of toxic chemicals such as DDT in agriculture can lead to serious problems particularly in the chemically sensitive subject.


Pharmacological Reactions are particularly important in clinical practice and produce recognizable clinical syndromes. These will be discussed in detail and include caffeine effects such as a) palpitations and paroxysmal tachycardia, b) indigestion and vomiting, c) anaemia and 3) anxiety states. The recognition and management of these syndromes will be described. Other pharmacological reactions include the production of headaches by amines, and the long-term effects of excessive salt intake which can lead to hypertension in susceptible subjects.


Food Allergy is an important cause of disease in susceptible subjects. IgE reactions occur rapidly and are easily recognized by the patient. The more common slow reactions, possibly initiated by immune complexes are responsible for a much wider range of symptoms and are more difficult to identify. Immunological reactions to food are, however, very common and most individuals have IgG antibodies to common foods, and the relevance of these findings will be discussed.