Almond milk, macadamia milk, rice milk… the list of alternative new ‘milks’ is ever-expanding.

The latest culprit? Oat milk. You’ve probably noticed it popping up on supermarket shelves (or at least your local hipster café). But, before you change your coffee order, you might be wondering how it ranks in the nutrition stakes. So, here’s your dietitian-approved answer.

The base: oats

You’ve probably heard dietitians bang on about the nutritional benefits of oats – and I’m no exception!

I’m always recommending oats as a healthy breakfast choice, because they’re full of fibre, which is key for a healthy gut. What’s more, they contain a specific type of fibre known as beta-glucan, which can help to reduce cholesterol.

Slow-burning energy is another benefit of the humble oat. This helps to keep you feeling full and satisfied (and less likely to reach for a sweet treat come morning tea).

In comparison to other grains, oats are also quite high in muscle-building protein, with half a cup providing almost 8 grams.

And finally, as a wholegrain, oats provide a range of micronutrients, like energising b-group vitamins, iron for oxygen transport and the antioxidant, Vitamin E.

So then, oat milk is healthy?

Well, not so fast! While oats themselves are what I’d call a true superfood, the ‘milk’ might not be so promising.

You might be surprised to learn that oat milk contains only 15 per cent oats. The majority of it is just water, with some added salt and oil. That’s not to say it doesn’t contain the goodness of oats as listed above – just far less than you probably initially thought.

Unlike regular milk, oat milk is also naturally low in calcium, which is key for strong bones and teeth. But, you can get varieties that have added calcium, so it pays to check the label.

What about good old cow’s milk?

To get you up to speed, here’s a blow-by-blow nutrient comparison of a leading brand of oat ‘milk’ and the bottle of skim milk I have sitting in my fridge.

One cup of skim milk contains 91 calories, 8.5g protein, 0.3g fat, less than 0.3g sat fat and 13.3g sugar (don’t freak out – it’s just lactose, the natural sugar found in milk). There’s also a whopping 300mg of calcium. That’s about a third of the recommended intake for women between the ages of 19-50.

One cup of oat milk, on the other hand, has 178 calories, 2.5g protein, 5g fat, 0.8g sat fat and 4.5g sugar. As it’s made with oats, the same quantity also offers 3.8g fibre, which is an added bonus. Now for the sticking point: some oat milks have added calcium and can provide just as much as cow’s milk – but others are lacking in this vital nutrient.

The verdict

As you can tell, oat milk can offer some valuable nutrition. If you choose to drink it, my top tip is to ensure it is fortified with calcium.

But, in my opinion, I think that oats should be left in your breakfast cereal and muesli bars. If you can have it, cow’s milk is brimming with a range of nutrients – not just calcium for strong bones and teeth, but also protein for muscle maintenance and repair, and a range of micronutrients, like Vitamin A, Vitamin B12 and zinc.

Melissa Meier is a Sydney-based Accredited Practising Dietitian. You can connect with her at www.honestnutrition.com.au, or on Instagram @honest_nutrition.