The Ultimate Guide to Oats


Oats are a great source of whole grains and contain a heart-protective starch called beta-glucan that can help lower cholesterol. Their high levels of fibre make them a satisfying option for breakfast. They are low GI, high in resistant starch (feeding the good gut bacteria) and can help improve digestion and promote regularity.


The Oat Plant and Gluten


It is always good to see where your food comes from! Oats are a species of cereal grain grown for its seed. There is currently no test for gluten in oats.


The term ‘gluten’ is used to describe the storage proteins from wheat, rye, barley and oats that are toxic to people with coeliac disease. The storage proteins from each grain are:

  • Wheat – Gliadin
  • Barley – Hordein
  • Rye – Secalin
  • Oats – Avenin

In people with coeliac disease, ingestion of these proteins results in an immune reaction. The current tests for gluten in food can measure gliadin, hordein, and secalin but not avenin. Hence, the Australian Food Standards Code prohibits the use of a ‘gluten free’ claim on oat containing products.

While uncontaminated oats are well tolerated by most people with coeliac disease for some people with coeliac disease, oat consumption can trigger a potentially harmful immune response. A lack of symptoms when consuming oats does not necessarily indicate that the oats are not causing bowel damage, as damage can still occur despite the absence of symptoms.

It is recommended that individuals who wish to consume oats as part of their gluten free diet do so under medical supervision to ensure appropriate review and safety. Undertaking a gastroscopy and small bowel biopsy before and after 3 months of regular uncontaminated oat consumption can help guide whether an individual with coeliac disease can safely consume oats.


Unhulled Oats
Contain the inedible outer layer or ‘hull’ of the oat grain or ‘groat’. Oats in this form are often used as livestock feed.


Hulled oats
Are unhulled oat groats with the outer, indigestible hull layer removed. They take the longest to cook and can be bought from health food shops.


Steel cut oats
Are hulled oats, cut into smaller pieces. These are the most unprocessed form that humans usually eat and are high in fibre. They have a chewy texture and nutty flavour.


Traditional rolled oats
Steamed and flattened oat groats, to help reduce cooking time. They are often used in baking as absorb fluid easily and retain their texture during the cooking process. Eating them soaked but uncooked also maximises their resistant starch content – which is the ‘bomb’ when it comes to happy gut bacteria.


Quick or instant oats
Are precooked, dried, and rolled thinner than traditional oats. When time is short, they still provide a good level of satiety, but I recommend getting the plain version and adding your own toppings like fruit, cinnamon, nuts and seeds.


Oat bran
Oat bran is the outer layer of the oat groat, which sits just beneath the inedible hull. While oat groats and steel-cut oats naturally contain bran, oat bran is also sold separately as its own product. Because oat bran is just the bran, and does not contain the germ or the endosperm, it is not considered a whole grain.


Oat flour
Oat flour is a wholegrain flour made from blended traditional oats. It is easy to make at home using traditional rolled oats and a food processor.

Despite the differences in processing, all oats retain a high level of nutrients making them much more nourishing than many other, more highly processed cereals.

Reference: Coeliac.org.au Position Statement