By Dascha Weir, MD
This article was originally published in the October 2016 issue of Celiac Digest, the Celiac Kids Connection newsletter.
For people with celiac disease, oats have become complicated. It used to be quite straightforward. While pure oats had been shown to be safe for most people with celiac disease (CD), they were not readily available.
Not so long ago, commercially available oats were all contaminated with wheat (or barley or rye) in the process of cultivation, transport, processing and packaging. They were simply not safe, so the gluten-free (GF) diet was defined as the elimination of wheat, barley, rye, and oats.
The development and increasing availability of so-called GF oats has broadened our options but also has created questions about the reliability and safety of our food.
The initially available GF oats were carefully grown on dedicated GF fields and transported, processed and packaged in specialized GF environments. These contamination-free or “purity protocol” oats are GF and well-tolerated by most people with CD.
However, “gluten-free” oats are no longer all “purity protocol” oats. Mechanical optical sorting, new technology developed to render conventionally grown oats GF, is now widely used. Oats used in foods labeled as GF may now include oats that have contact with gluten-containing grains in the fields or during harvesting and processing but are then separated from wheat, barley and rye by color, size and shape. This sorting process, while theoretically sound, has not been proven to consistently produce oats that are <20 ppm gluten and safe for people with CD.
As with many aspects of the GF diet, the devil is in the details.
Tricia Thompson of Gluten Free Watchdog, along with other CD experts, has drawn attention to these complexities. Ultimately, this sorting technology is only as good as the rigorous testing protocol used along with it to ensure the sorting worked. It is essential to confirm that gluten is reliably removed from sorted oats.
Gluten screening in foods is a complex task, from choosing the right test to ensuring that the food is appropriately sampled. For example, a recent article by Fritz et al in the journal Food Chemistry (1), highlighted that the process of grinding oats for testing can unevenly disperse gluten in a sample so that a single test may inadequately capture the entire gluten risk present.
Gluten Free Watchdog has reported that 14% of the oat products they have tested were above 20 ppm. For these reasons, at this time, we strongly urge skepticism about mechanically sorted GF oats and now recommend avoiding these products.
The bottom line is that “gluten-free” oats may be inconsistently GF. It is important to know what kind of oats you are buying. Determine the oat supplier of your favorite granola or other oat-containing foods. It is important to find out if the oats in your GF-labeled foods are purity protocol oats or not. Your CD dietitian and resources like Gluten Free Watchdog can be helpful, but the best way to get up-to-date information is still to question the manufacturer directly.
(1) Fritz et al. Gluten-containing grains skew gluten assessment in oats due to sample grind non-homogeneity. (2017) Food Chemistry. 216, 170-175.