This is the first randomised, double blind, multicentre study of the suitability of oats for children with newly diagnosed CD. Our results indicate that oats in a GFD do not prevent normalisation of the small bowel mucosa or coeliac serology markers. This is in accordance with previous open studies in a small number of children.17,18
Similarly, absence of oats toxicity was reported in adults with CD7–9,19
and dermatitis herpetiformis.20,21
Also, in vitro studies of duodenal biopsies cultured with avenin did not reveal any immunogenicity.22,23
It is important to note that all of these studies, including our own, presented short term results for diet test periods of up to 24 months. Absence of signs of toxicity of oats does not exclude the possibility of long term complications.24
However, Janatuinen et al
performed a follow up study25
in adult coeliac patients.7
At the time of re-examination, study patients had been on a GFD, including a daily intake of 50–70 g of oats, for five years. Compared with a control group of coeliacs on a standard GFD, there were no significant differences regarding the architecture of the duodenal mucosa or serum antibodies to endomysium, reticulin, or gliadin. The results of the study, although questioned because of the small number of patients involved, suggest that moderate amounts of oats are safe for patients with CD.26
Early reports on the tolerability of oats in patients with CD indicated a probable noxious effect on the small bowel mucosa.6
These studies were based on a small number of patients and performed without access to current antibody assays. However, Lundin and colleagues27
recently reported a case study questioning the lack of toxic effects of oats in a patient with CD. This necessitates caution and calls for further study of the long term effects of oats.
This is the first study on the effects of oats in a large population of children with newly diagnosed CD. Unfortunately, we were not able to fully achieve our aim regarding the amount of oats intake in the patients studied. This may be due to the design of the blinded study products. Some children had difficulty in consuming adequate amounts of oat products towards the end of the study year. According to a microchallenge study performed by Catassi and colleagues,28
a daily dose of 100 mg of gliadin was enough to significantly increase the IEL count. As 100 mg of avenin is equivalent to approximately 7.7 g of oats,2
we considered 8 g of oats daily to be the smallest quantity necessary to have a possible effect on the IEL count. However, there was no significant difference between children consuming at least 8 g of oats daily at the end of the study (GFD-oats
8 g) and children in the GFD-std group (table 3).
Withdrawal frequency was high but was not caused by the presence of coeliac symptoms in the majority of cases. When comparing the frequency of withdrawal because of symptoms between the groups of children under and over two years of age, there were significantly more children in the younger age group that withdrew (p
0.01). The reason for this difference may be that small children do not tolerate oats in their diet. Whether this intolerance is due to coeliac disease and the effect of the prolamin avenin, or something else in oats, such as the high fibre content, was not investigated in this trial. Further studies are needed to investigate if there is a subgroup of coeliac patients intolerant to oats. Also, whether this inability to eat oats is immunological or due to the fibre content of the oats containing diet should be investigated.
This study was originally designed to be analysed on an intention to treat basis. However, in some of the dropout patients there was no proper follow up. Thus we lacked some vital data which makes it impossible to perform an intention to treat analysis.
It is well known that coeliac patients have great difficulties in maintaining a strict GFD. Kumar and colleagues,29
for instance, reported a dietary compliance of 44% in teenagers with CD. One reason for this low compliance is probably the poor palatability of the comparatively low fibre standard GFD, which can be much improved by the addition of oats. It must however be emphasised that all commercial oat products used by coeliacs should be free of wheat contamination and this should be clearly marked on the packet.
In Sweden, 64% of all small bowel biopsies performed on children with suspected CD are capsule biopsies and only 36% are performed endoscopically.30
Accordingly, the majority of small bowel biopsy specimens from coeliac children in our study were obtained by capsule. This usually permits only one or two mucosal samples to be taken, in contrast with endoscopic small bowel biopsy yielding several specimens. There is thus a theoretical possibility that biopsies in the present study could have missed patchy small bowel mucosal lesions. However, there was no significant difference in antibody titres between our study groups, which indicates lack of humoral immunological response to oats.22
In conclusion, this randomised double blind study provides evidence that the presence of moderate amounts of oats in a GFD in children with CD does not prevent clinical or small bowel mucosal healing, or humoral immunological downregulation. This finding is in accordance with previous open studies in coeliac children and adults, and indicates that oats can be safely included in a GFD for the majority of children with CD. To confirm this, long term studies of the effects of oats in coeliac children are needed.