Oats in the gluten-free diet. With special reference to clinical, serological and nutritional effects, subjective experiences and the need for special oat products
Oats have for over 50 years been excluded from the gluten-free diet (GFD). The scientific basis for this recommendation is weak, and two studies performed during the 1990's stated that moderate amounts of oats were well tolerated in the GFD of adults with celiac disease (CD), followed for 3-12 months. The aims of the present investigation were to study the clinical, serological and nutritional effects of including large amounts of guaranteed not-contaminated oats, for a period of two years, in adult subjects with CD in remission. We were also interested in whether commercial oat products are suitable for subjects with CD, i.e. not contaminated with gluten. No adverse effects of a large intake of oats (median 93g/d) were seen in small bowel histology, serology nor in nutritional status in the 15 subjects who completed the 2-year study period. Anti-avenin antibodies were not induced after inclusion of oats. This has not been investigated in previous clinical studies. Beneficial effects were seen, as the intake of iron, fibre, zinc and thiamin increased when oats were included in the diet. The bioavailability of iron tended to decrease due to large amounts of phytate in oats but this seems not to have influenced the iron status of the participants. Temporary gastrointestinal symptoms, mainly flatulence and distension of the bowel, were observed, as were subjective improvement of the bowel function. Oats in the diet were appreciated by the subjects, who found that oats gave more variation, better taste and satiety. The analysis of the commercially oat products showed that contamination by wheat, rye and/or barley occur. The same picture was noted in products naturally gluten-free (NGF), analysed for comparison. In conclusion: adult subjects with CD in remission can include large amounts of not-contaminated oats in their daily GFD for an extended period of time without adverse effects. Beneficial effects were seen in nutrient quality of the diet and subjective experiences. However, only special oats and NGF products can be recommended in the GFD due to risk of contamination
