Food hypersensitivity

Haukelandsmodellen

Food hypersensitivity: Why is it so difficult?

Av Jørgen Valeur

Food hypersensitivity is common in the general population, and can be problematic for both the patient and the physician. Often, the physician cannot find an objective explanation and becomes uncertain of the diagnosis, and the patient loses confidence and feels that she is not taken seriously.

Few organ systems in the body are more challenging to investigate than the digestive apparatus. The gastrointestinal tract contains almost as many nerve cells as the spinal cord, and is, in addition, the largest hormone producer in the body. Together with the brain, the gut neuroendocrine system regulates all activity in the gastrointestinal tract, and hence governs the entire digestive process. The communication between the enteric nervous system and the central nervous system is bi-directional. This gut-brain-axis can, among other things, explain the intimate connection between mood and digestion. The gastrointestinal tract also contains an extensive bacterial flora, and has a well-developed immune system that protects the body against unwanted intruders. There is an extensive interplay between the neurological, endocrinological, microbiological and immunological components of the gut, and intake of food affects all of these systems.

The term ‘food hypersensitivity’ covers both immunological (allergy) and non-immunological (intolerance) reactions to food. Around 25% of the population claim intolerance towards certain foodstuffs, but only a few of these have “true” food allergy. What is wrong with the majority of the patients with self-reported food hypersensitivity is still largely unknown – and paradoxically, the health care system shows little interest in investigation and care of these “problem patients”.

Since 1996, adult patients with food hypersensitivity from all over the country have been examined at Haukeland University Hospital, by clinicians with expertise within allergology, gastroenterology, clinical nutrition and psychology/psychiatry. In 2001, this collaboration was strenghtened, as the MAI group (MAI = MatAllergi og –Intoleranse = Food Allergy and Intolerance) was established. Clinical work and research has all along gone hand in hand, and several master students and PhD fellows at the University of Bergen are associated with the team. The group has strong collaboration partners, including RECS (Research Group on Experimental and Clinical Stress) at the Faculty of Psychology (UoB) [http://www.psyfa.uib.no/index.php?valg=nysql&id=171⊂=116&sub2=120], NIFES (National Institute of Nutrition and Seafood Research) [http://www.nifes.no/index.php?page_id=126], and Uppsala University [http://www.uu.se] and Karolinska Institutet [http://ki.se] in Sweden. The MAI group performs research on several aspects of food hypersensitivity, including immunological, microbiological, neuroendocrinological and psychological topics.

Cognitive (central) sensitization seems to be at least as important as immunological (peripheral) sensitization in the pathogenesis of food hypersensitivity. It has been demonstrated, for example, that mast cells can be activated both by allergens (via IgE antibodies bound to the mast cell surface) and stress (via nerve fibers from the brain to the mast cell), showing that both allergy and anxiety can cause the same symptoms. It may not be so strange, therefore, that precise diagnosing is difficult? Haukeland University Hospital is so far the only hospital in Norway that offers holistic and multidisciplinary investigation and treatment of patients with food hypersensitivity.