Dietary analysis in symptomatic patients with coeliac disease on a gluten-free diet: the role of trace amounts of gluten and non-gluten food intolerances

Scand J Gastroenterol. 1999 Aug;34(8):784-9. doi: 10.1080/003655299750025714.


Background: Whereas many people with coeliac disease (CD) are asymptomatic when consuming a gluten-free diet (GFD), a proportion continues to experience symptoms. The reasons for this are unclear.

Methods: Thirty-nine adult members of The Coeliac Society of New South Wales, all of whom had persistent gastrointestinal symptoms despite adhering to a GFD, were evaluated. Dietary analysis indicated that 22 (56%) were consuming a GFD as defined by the WHO/FAO Codex Alimentarius (Codex-GFD), in which foods containing up to 0.3% of protein from gluten-containing grains can be labelled as 'gluten free'. The remaining 17 were following a no detectable gluten diet (NDG)-GFD, as defined by Food Standards Australia. All subjects were required to follow a NDG-GFD during the study. Those in whom symptoms persisted after changing from a Codex-GFD and those who entered the study already on a NDG-GFD began an elimination diet followed by open and double-blind challenges to identify specific non-gluten food or food chemical intolerances.

Results: Of 22 patients who switched to a NDG-GFD symptoms resolved in 5 (23%) and were reduced in 10 others (45%). Thirty-one subjects commenced the elimination diet. Symptomatic improvement was experienced in 24 (77%). Subsequent food or food chemical challenges resulted in a mean of five positive challenges per individual. Diarrhoea was the most commonly provoked symptom, followed by headache, nausea, and flatulence. Symptoms were especially provoked by amine, salicylate and soy.

Conclusion: The consumption of trace amounts of gluten, traditionally allowed in a Codex-GFD, may be responsible for the continuing symptoms seen in some patients with CD. Further investigation for non-gluten food intolerances should follow if symptoms persist after adherence to a NDG-GFD.

MeSH terms

  • Adult
  • Aged
  • Amines / adverse effects
  • Animals
  • Biopsy
  • Celiac Disease / complications*
  • Celiac Disease / diet therapy*
  • Celiac Disease / pathology
  • Celiac Disease / physiopathology
  • Diet Records
  • Female
  • Food Hypersensitivity / complications*
  • Food Hypersensitivity / diagnosis*
  • Food, Formulated
  • Glutens / adverse effects*
  • Humans
  • Intestine, Small / pathology
  • Male
  • Middle Aged
  • Milk / adverse effects
  • Nutrition Assessment
  • Panicum / adverse effects
  • Salicylates / adverse effects


  • Amines
  • Salicylates
  • Glutens