Coping with food allergies

There are many reasons for responding negatively to otherwise healthy foods. Generally, these are called food sensitivities. If the abnormal reaction is related to your immune system, this is called a food allergy and the offending substance is called a food allergen. If symptoms are due to other reasons such as enzyme defects, food toxins or other substances in food, then you are said to have a food intolerance.

When food is the villian

Adverse effects reactions can be experienced by anyone, but a few are particularly sensitive to some foods. There are two main types of food sensitivities. True food allergy occurs when the reaction is due to an immune response while the others are due to various types of non-allergic food sensitivities

The intestinal permeability test applied to the diagnosis of food allergy in paediatrics

Intestinal permeability was evaluated in 17 healthy children (control group), aged 4.3 ñ 1.9 years (mean ñ SD), weight 15.4 ñ 5.5 kg and in 11 infants with food allergy (allergic group, aged 2.3 ñ 1.6 years, weight 9.5 ñ 1.5 kg). In the two groups, the urinary excretion of two non-metabolized sugars (mannitol, lactulose) was measured by gas-chromatography after oral administration. Measurement of urinary content of these sugars 5 hours after administration in the control group showed a clearance of 20.2 ñ 8.6 percent for mannitol and 0.44 ñ 0.81 percent for lactulose. The lactulose/mannitol ratio in the same group presented a normal mannitol urinary excretion (16.5 ñ 13.4 percent, p = NS, Student's t-test) and an increase in the lactulose excretion (1.36 ñ 0.92 percent, p<0.001). Moreover, the allergic group showed a lactulose/mannitol ratio that was significantly different (0.105 ñ 0.071,p<0.001). The intestinal permeability test for the diagnosis of food allergies seems to be sensitive and non-invasive test that is well suited to the paediatric practice (AU)

Allergy in the West Indies - abstract

Allergy-related illnesses (respiratory, food and others) occur frequently in West Indians. A prospective study of 1038 Jamaican adolescents revealed high levels (males 52 percent, females 41 percent) of allergy prevalence. The respiratory allergies were the most common; 21 percent of the allergic subjects gave a history of bronchial asthma. Only 19 percent of the latter group had their illness diagnosed by a doctor. A retrospective study of 512 patients in a local allergy practice showed that respiratory allergies usually occurred perenially, and the patients' skin tested positive to house dust mite, moulds and pollens. Immunotherapy was effective if very dilute dosages were used. Laboratory investigations of allergic and non-allergic medical students and technologists at the University of the West Indies revealed normal total serum IgE levels (0-380 kU/L) in 18 of 24 subjects and only moderately elevated levels in the remaining 6 subjects. Total serum IgG4 was unexpectedly found to be increased in most of the study subjects (18 of 24). Further studies are necessary to further clarify these findings (AU)

Immediate hypersensitivity in colon of children with chronic Trichuris trichiura dysentery

There are few data on mucosal immune responses to intestinal helminths in human beings, especially those involving the IgE system, which is thought to be important in parasite expulsion. We sought evidence of an immediate hypersensitivity reaction in the colon of children with chronic dysentery due to Trichuris trichiura. 28 children with Trichuris dysentery syndrome (TDS) were compared with 16 control children (with no TDS or worms visible on colonoscopy). All children were aged 1-11 years. Rectal biopsy samples were taken before and after expulsion of the worms by means of mebendazole treatment. Children wtih TDS had significantly greater numbers than controls of mast cells (mean [SD] 10.9 [1.3] vs 3.9 [0.6] percent of all cells; p<0.0003) and of cells with surface IgE (median [range] 11.1 [7.5-11.6] vs 1.0 [0-1.5] percent; p<0.001) in the subepithelial region of the mucosa. On electronmicroscopy, degranulating mast cells were prominent in parasitised children. In culture, rectal biopsy samples from parasitised children showed high rates of spontaneous histamine release, but only low rates of antigen-specific release. After treatment, spontaneous histamine release was significantly reduced and antigen-specific histamine release could be provoked. Thus, an IgE-mediated immune mucosal response to a helminth infection does occur in human beings but is not sufficient to cause appreciable parasite expulsion. (Summary)

The human rumen

The cow is a ruminant, and cow's milk has evolved to promote bacterial growth in the upper small bowel; whereas human milk has evolved to discourage bacterial growth. Examinations of the constituents of the two milks shows that their differences can be accounted for in terms of this difference in function. Children who are fed a calf's diet tend to develop a rumen. This may lead to chronic diarrhoea and malnutrition and may be a factor in diarrhoea ascribed to cow's-milk-protein allergy and lactose intolerance (Summary)

Assessment of the effects of ascorbic acid on respiratory and alimentary immune reaction

Clinical observation of diseases associated with the occurence of upper respiratory symptoms indicates that clinical features are also present in the alimentary system. Respiratory symptoms occur in consequence of viral or allergic reactions in the respiratory tract, both of which are associated with changes in ascorbic acid metabolism. Alimentary allergic symptoms occur as a rsult of recurrent antigen challenge with specific foods to which patients are sensitive. The specific allergens cause alteration in buccal taste and sensation, and the occurrence of abdominal symptoms. These effects provide sensitive and precise methods for diagnosis of food allergens. Aphthous ulceration has been shown to have a specific allergic basis by challenge of the ulcers with the causative allergens. The pain and inflammation of aphthous ulcers can be completely alleviated by buccal administration of ascorbic acid. The simultaneous occurrence of respiratory and alimentary symptoms following allergenic challenge indicates their common etiology in the allergic syndrome. The beneficial effect of ascorbic acid in the allergic syndrome is discussed. The lay person has a clear definition for himself of the symptoms which make up a cold. For the doctor Tyrell defined a cold as a mild illness in which the main local symptoms are found in the upper respiratory tract and in which nasal symptoms predominate. The early features are produced as a result of primary infection of the nose and nasopharynx by several viruses especially the rhinovirus. Amongst the complications of a cold, however, Macleod only includes sinusitis, eustachian catarrh, and lower respiratory infection. Clinical observation of diseases associated with the occurrence of upper respiratory symptoms indicates that many other features may be present in addition to those occurring in the respiratory tract. The purpose of this paper is to analyse these features, to determine their relationship to each other, and to investigate the effects of administration of supplementary Vitamin C on them. (AU)