The most elemental fact related to starting a gluten-free diet is what grains contain gluten: wheat, barley, and rye (as well as any derivatives or hybrids of these grains). Oats come up as something which should also possibly be avoided. Why is this? There are several issues behind the confusion on this topic. Let’s take a closer look to help get this sorted out.
* Are some people with celiac disease sensitive to oats?
Oats contain “avenin”, a type of storage protein in plants. Avenin has been thought by some to potentially cause a reaction similar to that of gluten, in some individuals with celiac disease. Research has indicated, however, that the vast majority of people with celiac disease do tolerate oats, as long as they are pure and un-contaminated. It is recommended that individuals with celiac disease consult with their healthcare team before introducing pure, un-contaminated oats into the diet, and limit intake to ½ cup dry oats per day.
* Cross-contamination. Cross-contamination with barley or wheat is the primary, and legitimate, concern regarding oats.
Because oats are often grown and processed in close proximity to barley and wheat, and also because of similar grain size, risk of cross-contamination is significant, and people with gluten-related disorders should avoid any oats which are not certified or labeled gluten-free. It is believed that some instances of celiac patients’ reporting a sensitivity to oats (see above) were actually due to cross-contamination, and not related to the oat grain itself.
* What does “purity protocol” mean vs. “mechanical sorting” and what bearing do these terms and processes have on gluten-free status of oats?
First, if an oat product is certified gluten-free by GFCO you can be confident that it is safe to consume, and you do not need to be concerned with details of the protocols or “sorting” processes followed by the manufacturer.
“Purity Protocol.” There is as yet no required protocol for assuring purity, so simply knowing that oats were processed according to “a” “purity protocol” is not sufficient to ensure their safety. Working towards clarifying this situation, GIG worked in collaboration with oat processors to develop an industry agreed-upon definition and related requirements. This protocol was recently published in the journal Cereal Chemistry. This publication describes the lengths that growers and processors must go to in order to meet the GFCO 10 ppm threshold, as well as the GFCO requirement that all whole gluten-free grains certified by GFCO contain less than 0.25 gluten-containing grains per kilogram, or less than one whole gluten-containing grain per every 4 kilograms.
“Mechanical Sorting.” As the term implies, this is a process in which foreign substances (e.g. wheat grains) are sorted out of oats via differences in length, density, color and other physical properties. As with oats sold under a “purity protocol” claim, these should be avoided unless it can be confirmed that the final product meets the FDA threshold of gluten-free (20 ppm) or the GFCO standard of containing no more than one gluten grain for every 4 kilograms of oats.
- Uncontaminated, certified gluten-free oats are considered safe for most people with celiac disease. Consult with your personal healthcare team before introducing oats into the diet. Quantity should be limited to the recommended maximum of ½ cup dry oats per day.
- The main issue surrounding oats for those following a gluten-free diet is cross-contamination. In light of the fact that purity protocols are not regulated, and that mechanical sorting can vary from processor to processor, only consume oats which are labeled – and preferably certified – gluten-free.
– Allred LK, Kupper C, Iverson G, Perry TB, Smith S, Stephen R. Definition of the “Purity Protocol” for Producing Gluten-Free Oats. Cereal Chem. May/June 2017. 94(3): 377-379
– Gilissen LJWJ, van de Meer IM, Smulders MJM. Review. Why Oats Are Safe and Healthy for Celiac Disease Patients. Med. Sci. 2016, 4, 21; doi: 10.3390/medsci4040021
– Lionetti E, et al. Safety of Oats in Children with Celiac Disease: A Double-Blind, Randomized, Placebo-Controlled Trial. The Journal of Pediatrics. DOI: https://doi.org/10.1016/j.jpeds.2017.10.062