Royal Prince Alfred Hospital Royal Prince Alfred Hospital
Allergy Unit

Student research

Different dietary gluten restrictions
and symptom expression in a large population
of people with coeliac disease

Michelle Stewart
Master of Science (Nutrition and Dietetics), University of Wollongong
Supervisors: Kim Faulkner-Hogg, Robert Loblay, Warwick Selby
June 1997

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The treatment for coeliac disease is a gluten free diet. Whether it is safe for coeliacs to ingest the minute amounts of gluten often found in gluten free diets is still controversial. The WHO/FAO Codex Alimentarius allows 0.3% protein from gluten containing grains in foods labelled as gluten free. This is thought to be the standard upon which gluten free diets are based in research studies and which is adopted as practice in many countries including Australia in the past. In March 1995 the Australian standard for gluten free food labelling changed from this WHO guideline. Currently a food cannot be labelled gluten free if it contains any detectable gluten. This study set out to examine the dietary patterns in a large population of subjects with coeliac disease and to relate any symptoms being experienced to the different levels of gluten restriction. This may help to determine if the dietary advice given to all coeliacs should now fall in line with the new Australian food standard for gluten free food labelling. Of the 1672 questionnaires sent to members of the Coeliac Society of NSW, 965 (58%) were returned. This questionnaire asked for a graded description of the severity and frequency of gastrointestinal symptoms commonly experienced by coeliacs, and other less commonly related symptoms. Food brand selection questions were asked so classification into one of three diet categories could be made. The categories were: overt gluten ingestion; trace gluten ingestion in accordance with the old Australian food standard and no detectable gluten ingestion as in the new Australian guidelines. Of the 71.9% of the respondents with trace gluten ingestion, 73% stated that they were not aware of ingesting gluten. After diagnosis and commencement of gluten restriction, a large proportion were still experiencing symptoms but generally found them to be less frequent and less severe. The frequency and severity of symptoms was greater at gluten intakes above that allowed in the old Australian gluten free diet. A comparison of symptom expression between the trace gluten and no detectable gluten diets revealed that only 2 of the 13 symptom categories were significantly different (p<0.01). Constipation was more severe (p=0.0051) in the trace gluten group, while diarrhoea occurred more frequently in those consuming no detectable gluten. The lack of differences in symptoms seen between the trace gluten and no detectable gluten diet categories would suggest that the less restrictive trace gluten diet may be appropriate for some coeliacs.