Battle of the Oats: Steel-Cut vs Rolled

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Steel-cut oats have become an increasingly popular choice in the health/foodie worlds. Regardless of the type of oats, when you pop them in your mouth you’re treating your body to fibre, protein, beneficial fats, micronutrients and phytochemicals. However, as with most foods, the less processed oats tend to be more nutritious than highly processed ones (eg: quick oats, sweetened products). For this reason steel-cut oats are sometimes promoted as a better choice than the traditional rolled versions. Here we compare the nutritional value of these two less-processed choices.

Key Points:

1. As far as grains go, oats are a good choice for the decent protein and calcium, and high amounts of essential fatty acids, fat-digesting enzymes and fibre provided.
2. Steel-cut are the least processed variety of oats available and therefore have been touted as the best choice.
3. Despite this, the information we have suggests there isn’t a significant difference between steel-cut and rolled oats. Additional studies and data may alter this conclusion in future, but as yet there’s no proof that steel-cut are definitely nutritionally superior. 

Nutritional value of oats in general

Relative to some other grains, oats contain decent amounts of protein and calcium, and  are high in fat (i.e. they’re composed of 6-8% fat versus most other grains at 2-3%). More importantly, they are high in monounsaturated and polyunsaturated fatty acids, including the essential omega-6, linoleic acid. To demonstrate this, the table below compares protein, calcium and unsaturated fats provided by steel-cut oats, pearl barley, weetbix, and white rice. Note these figures are averages adapted from FSANZ’s Australian Food Composition Database, and they may differ from those of individual products and from data that has been obtained elsewhere.  

	Steel-cut oats, uncooked (100g)	Pearl barley, uncooked (100g)	Weetbix (100g)	Whole wheat, uncooked (100g)	White rice, uncooked (100g)
Protein	11.7g	10.1g	12.1g	11.5g	7.3g
Calcium	37mg	28mg	31mg	35mg	4mg
Monounsaturated fat	4.32g	0.36g	0.28g	0.36g	0.26g
Polyunsaturated fat	3.2g	1.37g	1 g	1.08g	0.34g

Accompanying the fats are large amounts of enzymes involved in digesting fats. In addition, oats are a good source of fibre, including beta-glucan (a soluble fibre which can help lower cholesterol levels). 

A lab study mimicking digestion has shown that wholegrain oat cereals may also have prebiotic properties, supporting the gut microbiota. 

Luckily, we’re able to enjoy oats with a greater variety and quality in flavour and nutrition than Oliver Twist did. 

Rolled versus steel-cut oats

To produce oats, their outer hull is first removed, then they are kilned (i.e. steamed, dried and cooled). Rolled oats are these whole oats, flattened after steaming, whereas steel cut oats are whole oats chopped into 2-4 bits. Steel cut oats tend to have a chewier texture and nuttier taste- and take longer to prepare.

In terms of the levels of nutrients provided, rolled and steel-cut oats are quite similar. As you see in the table below, perhaps the largest variance is in the caloric value, selenium and vitamin E levels. While steel-cut oats seem to provide marginally higher levels of some nutrients, rolled oats provide more of others.  However this should be taken with a grain of sodium (pardon the pun), as these values obtained from FSANZ’s Australian Food Composition Database are not necessarily representative of all oat products and testing procedures within different labs. In fact, while this hasn’t been found in this particular data set, it has been suggested that steel-cut oats may be higher in fibre.

	100g steel cut oats	100g rolled oats
Energy	1575kJ/ 376 calories	1889kJ/ 451 calories
Protein	11.7g	12.4g
Fat	9.8g	9.5g
Monounsaturated fat	4.32g	4.19g
Polyunsaturated fat	3.2g	3.1g
Fibre	8.6g	9.5g
Calcium	37mg	40mg
Iodine	74 ug	74 ug
Magnesium	117 mg	104 mg
Phosphorous	305 mg	310 mg
Potassium	310 mg	310 mg
Selenium	17 ug	6.5 ug
Sodium	4 mg	3mg
Zinc	2.3 mg	2.35mg
Thiamin (B1)	0.31 mg	0.39 mg
Riboflavin (B2)	0.01 mg	0.005 mg
Niacin derived equivalents	3.75 mg	3.96 mg
Folate	17 ug	17 ug
Vitamin E	0.48 mg	0.23 mg

It has also been suggested that steel-cut oats may have a lower glycaemic index- i.e. they increase blood glucose levels more gradually. However, the one systematic review I was able to find showed that both steel-cut and rolled oats made into porridge had similar, low-to-medium glycaemic responses. This may suggest the size of the oat fragments is the most significant effect of processing on GI, rather than the processing methods themselves. Of course, there being only two samples of steel cut oats analysed, it would be worth adding more to this list to increase the accuracy of data. 

However, as expected they definitely outperformed quick-cooking and instant oats. 

Steel-Cut Oats: The Verdict

Nutritionally speaking, it appears there is little difference in the nutritional value of steam-cut and rolled oats. We may obtain additional data from more thorough studies in future that suggest otherwise. In the meantime, though, it may come down to personal preference- either variety will do you good, beyond the benefits provided by highly-processed quick oats. 

How do you take your oats for a satisfying, sustaining meal?