Oat milk

Also called oat drink.

Dr Chad OkayFounder, Suna Health

3 min read. Updated .

Oat milk is a plant-based drink made from soaked, blended and strained oats. It is creamy, dairy-free, lactose-free, and naturally low in saturated fat. Its main downsides are a higher post-meal glucose response than dairy milk and lower protein content. Choose unsweetened, fortified versions and treat it as a milk alternative, not a one-for-one nutritional swap.

Nutrition vs cow milk

  • Calories: about 50 kcal per 100 ml (similar to semi-skimmed dairy).
  • Protein: 0.5 to 1 g per 100 ml (dairy is 3.4 g). Big gap.
  • Carbohydrates: 5 to 7 g per 100 ml (dairy is 4.5 g, mostly lactose).
  • Fat: 1.5 to 3 g per 100 ml depending on barista vs standard.
  • Calcium: only if fortified, check the label, target 120 mg per 100 ml.
  • B12: only if fortified.
  • Iodine: usually not added; relevant if oat milk replaces all dairy and you eat little fish.
  • Beta-glucan fibre: only a small amount, well below the 3 g per day shown to lower LDL cholesterol, so the cholesterol benefit from oat milk alone is minimal.

Glucose spike question

The carbohydrate in oat milk is mostly maltose (the sugar produced when oat starches break down during processing). Maltose has a glycaemic index near 100, similar to glucose. A 250 ml glass of oat milk on its own can spike blood glucose more than a glass of dairy milk would. Pairing oat milk with protein and fibre (in coffee with breakfast) flattens the spike substantially.

Gut effects

  • Naturally lactose-free, suits lactose intolerance.
  • Contains some beta-glucan, a soluble fibre that feeds beneficial bacteria.
  • Most commercial oat milks are NOT certified gluten-free; coeliacs should check the label.
  • A small minority of people are sensitive to oat avenin (a gluten-like protein) and react to oat milk too.
  • Generally well-tolerated for IBS in small amounts, though oat drinks become high-FODMAP at typical mug-size servings; on FODMAP composition testing only small servings (around 100 ml) stay low-FODMAP.

What to look for on the label

  1. Fortified with calcium (target 120 mg per 100 ml).
  2. Fortified with vitamin D and B12.
  3. Unsweetened or with under 4 g of sugar per 100 ml. Watch for added sugars in flavoured versions.
  4. Few additives. Many brands now use only oats, water, salt and oil.
  5. Certified gluten-free if you have coeliac disease.
  6. Avoid coconut oil-based oat milks if cardiovascular health is a focus (saturated fat content).

Why it matters for the long run

Over years rather than weeks, the things that matter about oat milk are the quiet ones: whether it is fortified (calcium, B12, and iodine if it has displaced all your dairy and you eat little fish), and how it lands in your glucose pattern day after day. Neither is a reason to avoid it. Both are reasons to read the label once and pair it with food rather than drinking it alone.

Common questions

Is oat milk healthier than cow milk?
Different, not strictly healthier. Cow milk wins on protein, calcium without fortification, and B12. Oat milk wins on saturated fat, lactose tolerance, and (modestly) cardiovascular markers. The best choice depends on what else is in your diet.
Why does oat milk cause a glucose spike?
Processing breaks oat starches into maltose, which absorbs almost as fast as pure glucose. Drinking oat milk on its own, on an empty stomach, spikes blood glucose more than dairy milk. Pairing it with food (especially protein) reduces this.
Is oat milk OK if you have diabetes?
Use carefully. Unsweetened oat milk in coffee with breakfast is fine. Oat milk lattes on an empty stomach are not ideal. Some people with diabetes switch to almond or soy milk, which tend to have a lower glycaemic index, though the difference between unsweetened plant milks can be small.
Why is barista oat milk so expensive?
Higher fat content (often added oils) and stabilisers help it foam without splitting. Worth it for coffee. Standard oat milk is fine for cereal and cooking.

Sources

Written by Dr Chad Okay. Contributor: Dr Parisah Hussain, MBChB, BSc (Hons), DRCOG, MRCGP. Last updated 15 September 2026. From Digests.

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