Oats and Coeliac Safe or Questionable?
If you have been diagnosed with coeliac or gluten sensitivity then the exclusion of wheat rye and barley will have been established as a vital component of your gluten free future. Oats however, will have been given the all clear due to the absence of the immune activating gluten proteins. Yet some studies have suggested that oat exposure may result in immune responses and prevent satisfactory recovery from gluten related damage.
This has normally been accounted for as a cross contamination issue where the transfer of food I bulk means that periodically oats and wheat are moved in the same vehicles. Whilst this is likely to be a factor a new study out in the international journal GUT suggests that individual oat species may have differing levels of impact from none to some and as a result may account for some of the confounding studies and experiences.[1]
Using monoclonal antibodies, a mechanism for identifying agents with immunological activation against the common peptide 33-mer found in gluten containing grains. However, it is not the only gluten peptide sequence which is harmful for patients with CD and, furthermore, patients with CD may react against glutenins found in these cereals.
Three distinct cultivar groups of oats were identified with different responses. This suggests that distinct sources of oats may have different levels of risk either independent of cross contamination or increased by contamination.
So what do we know?
The safety of oats in a gluten-free diet (GFD) has been a topic of debate for several years. At the nutritional level, oats are an important source of proteins, fat, vitamins, minerals, and fibres, and could therefore be beneficial for people with coeliac disease (CD). In addition, the palatability of oats and their wide availability could also contribute to the acceptability of a diet without wheat, barley and rye.
The difference in type of oats used, the purity and study design have not allowed a clear answer as to whether oats are safe or not for all patients with CD. Current beliefs are that pure oats are safe for most people with CD, and contamination with other cereal sources is the main problem facing people with CD.
What have we learned?
In this study we show, using a new antibody raised against the toxic fragment, that oat immunogenicity for patients with CD varies according to the cultivars. We could distinguish three groups of oat cultivars reacting differently against the antibody: a group with considerable affinity, a group showing slight reactivity and another with no detectable reactivity.
The incorporation of some varieties of oats in food products not only may improve the nutritional quality but may provide a treatment for various illnesses and would be welcomed by patients with CD. Our work may explain the apparently contradictory previous studies relating to the safety of oats for patients with CD. Our study provides new insights about the oat dilemma in CD and suggests practical methods to select tolerable varieties of oats for patients with CD.
Comment
Ingesting less than 20gm/day of oats further reduces any risk of immune activity in patients with CD and gluten sensitivity, but further analysis of distinct genus families of oats will probably lead to a more specific family being designated as a low responder risk cereal and in future we can expect growers to support this finding by further hybridisation and cross breeding.
References
[1] Comino I, Real A, de Lorenzo L, Cornell H, López-Casado MA, Barro F, Lorite P, Torres MI, Cebolla A, Sousa C. Diversity in oat potential immunogenicity: basis for the selection of oat varieties with no toxicity in coeliac disease. Gut. 2011 Feb 12.