Are Oats and Oat Flour Gluten-Free?

Published November 20, 2020

When a person has been diagnosed with celiac disease, being cautious about food and ingredients is essential to maintaining good health. Acting without caution, could cause serious illness. Accuracy in food labeling is something that the FDA regulates, including when it comes to packaged foods which are labeled gluten-free. * The FDA requires that labeling be truthful and not misleading, but does not actually verify or certify the gluten content in foods labeled gluten-free.

A grain that has become a hot button topic within the celiac and gluten-free communities is oat. Oats are not considered a top allergen. Unlike wheat, barley, and rye, oats are not considered a source of gluten in many countries. In their pure form, oats are gluten-free.

A small percentage of people who have been diagnosed with celiac disease appear to have adverse reactions to oats. For this reason, it is recommended that persons with celiac disease consult with their doctor before consuming oat products, and consider limiting the amount of oats they consume.

The concern with oats is that they could be “contaminated” by gluten grains from sources from the field to processing.  This is a valid one, leading many to ask the question “Are these oats really gluten-free?”

Here’s a breakdown of oats and oat processing to help clear up wide-spread confusion about the safety of oats as well as oat flour.


Fact 1: Oats are not considered a gluten source in many countries.

As we mentioned above, oats are not typically placed in the same category as wheat, barley, or rye when it comes to gluten regulations.

Canada, Europe, and many other countries follow a uniform set of guidelines to ensure food safety called Codex Alimentarius Standard_118-1979.The Codex includes oats in its definition of gluten grains. However, in a footnote, the Codex standard states that “Oats can be tolerated by most but not all people who are intolerant to gluten. Therefore, the allowance of oats that are not contaminated with wheat, rye or barley in foods covered by this standard may be determined at the national level.”

Most European countries allow oats in products labeled gluten-free, and Canada has issued a Market Authorization that allows oats in products labeled gluten-free, as long as they are specially grown or processed to ensure that they are gluten-free, and named accordingly.

An exception to this rule is Australia and New Zealand who include oats as a restricted grain along with wheat, barley, and rye in any gluten-free products produced or sold in those countries.  


Fact 2: Oat processors have different methods to make sure that their oats are gluten-free.

There are two main ways that oat processors currently avoid or remove potential agricultural co-mingling with gluten grains:

  1. During the growing, harvesting, transport and processing of the oats. There is a non-regulated set of steps that addresses these stages of oat production called Purity Protocol.
  2. During the cleaning and processing of the oats. A complex set of machines are used to sort oats to ensure proper size, shape, and color and to eliminate other particulates. This is called Mechanical Sorting.

These two methods are not exclusive, and some oat processors use a combination of them. Let’s dig into both of these areas of oat handling prior to packaging.

  1. Purity Protocol

Purity Protocol was developed by oat producers in Canada to meet Health Canada’s definition of “pure oats”, and these best practices were later adopted by some U.S. oat companies as a way to differentiate their oats from their competitors. The protocol is a set of steps growers and processors can take to minimize the risk of cross-contact (contamination) between their oats and errant gluten grains.

In order to create more consistency in the processes of the Purity Protocol, GFCO worked with oat producers to define the Purity Protocol practices.

  1. Mechanical Sorting

Sorting oats by machines may sound like a process that could create more opportunities for cross-contact. The interesting thing about mechanical sorting, however, is that it is a very extensive process with many steps that can literally identify and remove gluten grains, getting oats that much closer to being truly gluten-free. And because of the intricacies of the process and the machine settings, oat producers are not using their sorting equipment for handling other grains, so the process is dedicated to oats.

Producers of mechanically sorted oats often also institute requirements on their growers to make sure that the starting oats have as little contamination as possible, and they perform visual examination of the oats (done by trained personnel) on receipt to make sure the incoming oats meet their requirements. This same type of visual examination is also performed at the end of the sorting process, to be sure the sort was effective and if an unacceptable level of gluten grains are identified during the visual review, the machines can be recalibrated with new parameters and the oats can be run through the system again.

Potential cross-contact can happen at any stage of Purity Protocol or Mechanical Sorting, but both methods are effective ways of producing gluten-free oats.


Fact 3: A thorough third-party certification process can help ensure a gluten-free product

The requirements of certification are intended to help producers identify and remove potential risks of cross-contact with gluten.  Many of the Purity Protocol and Mechanically Separated oat producers come to the GFCO to have their oats certified.

Once oats are processed, testing at this stage can be part of verifying that the oats are actually gluten-free. Testing alone doesn’t guarantee a food item is gluten-free because there are many steps before and after testing where cross-contact could happen if proper procedures aren’t followed

Some people are concerned about oat flour and the chances of cross-contact during the milling of the flour, but oat flour, like any processed and packaged product, can be tested for gluten. In fact, oat flour is much easier to test for gluten than whole unprocessed oat groats because any gluten grains have been more evenly distributed through the flour, and are therefore easier to pick up in the smaller samples taken for testing. GFCO recognizes that the distribution of gluten in a milled oat flour is not 100% uniform, which is why all oat ingredients must be tested multiple times per container before they are used in a certified product.

Testing for gluten is just the final verification that a producer has taken the right steps to make a gluten-free product, but all of the steps before that are also essential. For example, the GFCO certification process includes 80 requirements for product certifications that apply to any product, including oats and foods containing oats. These requirements include:

  1. Supplier review and approval
  2. Purchasing protocols to make sure the materials purchased are gluten-free
  3. Examination and review of incoming shipments to make sure they are correct and that there has been no gluten cross-contact
  4. Correct storage of gluten-free and gluten-containing raw materials
  5. Proper facility set-up to avoid cross-contact
  6. Cleaning protocols and schedules
  7. Ongoing review of processes, particularly when there are changes in the plant
  8. Training of staff on gluten sources and health risks

You can review all of these steps listed at the end of the GFCO Certification Scheme Manual.

GFCO also maintains stricter criteria for gluten-free products than the FDA, namely in the amount of gluten allowed in a product: the FDA requires less than 20 ppm whereas the GFCO requires 10 ppm or less gluten content.  GFCO will not certify any foods, including oats or foods containing oats in any form, unless there is a high degree of confidence because they’ve passed the many criteria to earn the GFCO certification mark.


The Bottom Line about Gluten-Free Oats

When in doubt about the safety of oats, look for a mark on the packaging that says “Certified Gluten-Free” for peace of mind. Many of the Purity Protocol and Mechanically Separated oat producers still come to GFCO to have their oats certified. Gluten-free consumers should beware of oat products that are not labeled or certified gluten-free.

If someone believes they are sensitive to oats, then they should avoid oats. If someone is sensitive to gluten or has been diagnosed with celiac disease, looking for a reliable certification on the product – like the new GFCO certification mark (see below) – should offer the best assurances available that the product is safe. When one’s health is on the line, erring on the side of caution can be the best route, but understanding the science and the facts around gluten-free oats can help put their safety into perspective.

*The vast majority of packaged foods in the U.S. are regulated by the FDA.


The majority of information in the scientific literature supports the case that gluten-free oats are safe for the majority of individuals with celiac disease. That said, the recommendation is that oats only be introduced into the diets of those with celiac disease under the guidance of one’s personal healthcare team, and in limited amounts. In answer to the question of why oats should be included in the diet at all if there is any question as to their safety: oats are a good source of nutrients which are often lacking in the gluten-free diet, and in addition, since the gluten-free diet is already limited, adding additional restrictions can have negative effects on quality of life. This issue of oats can seem complex and confusing due primarily to the following factors: -Unless certified gluten-free, oats are commonly cross-contaminated with gluten-containing grains, potentially leading to the belief that the oats themselves are problematic, whereas in fact the issue is more likely to be cross-contamination with gluten. Over recent years, certified gluten-free oats (and products containing certified gluten-free oats or oat flour) have become more widely available, making this issue less prevalent. -Oats contain avenin, a storage protein which bears some similarities to the gluten found in wheat, rye, and barley. The amount is relatively small, and the research on sensitivity to avenin generally indicates that avenin does not elicit an adverse response in the majority of celiac disease patients. However, due to this possibility, it is recommended that the question of oat introduction be addressed on an individual basis, in consultation with one’s individual healthcare team, where any potential adverse reaction can be monitored.
We continue to monitor research and food safety issues in regards to oats and will continue to keep the community informed


 This information should not be used to diagnose or treat gluten-related disorders or other medical conditions.  For questions about these conditions consult your healthcare team when considering this information. Find out more about gluten-free living visit our website.