The Anti-Oat Milk Police: What Does The Research Say?

The global plant milk industry was worth a staggering $21.1 billion in 2024, and with its surge in popularity over the last few years, oat milk has become the darling of the “mylk” world. Its creamy, naturally sweet flavour and its reliability in knocking out a steaming mug of uncurdled coffee has raised the game regarding the sensory profile of plant-based milks.

From an environmental perspective, its processing produces lower levels of greenhouse gases than rice or soya. Although it requires more land for cultivation than its plant milk counterparts, evidence suggests it only requires 18% of the land use that dairy cows require.

Oat milk is not just a milk substitute for vegans or those with allergies or intolerances to dairy or other plant-based offerings; it is now a mainstay preference for many.

However, the growing wave of anti-oat milk claims has led to its fall from grace. Classified as an ultra-processed food (as all plant milks are), is oat milk the villain it is portrayed as, or is it being demonised based on hearsay rather than science?

Holly Rothschild, registered nutritional therapist at Integral Wellness, a blood sugar and metabolic health clinic, explains all.

Are oats good for you?

First things first, let’s dive in by looking at the nutritional benefits of oats…

• Fibre: rich in both soluble and insoluble fibre, with oat beta-glucan being a key soluble fibre with cholesterol-lowering and blood sugar control benefits when consumed at certain levels.
• Protein: compared to other grains, oats have a slightly higher protein content, with a 30g serving providing approximately 3.5g
• Vitamins and minerals: oats are a good source of manganese, phosphorus, magnesium, iron, zinc, selenium and B vitamins.
• Antioxidants: avenanthramides are unique to oats and have anti-inflammatory and anti-itching properties. Other nutrients in oats with antioxidant properties include vitamin E and plant sterols.

How do the benefits of oats convey to health?

Consuming oat products has been linked to lower serum cholesterol levels, a reduced risk of cardiovascular disease (CVD), and a decreased likelihood of developing obesity, hypertension, cancer, diabetes, and gastrointestinal issues.

Research consistently shows that oat beta-glucan (OBG) is responsible for lowering cholesterol and has been proven to lower post-meal blood sugar levels by slowing carbohydrate absorption. For these effects, foods must contain at least 4g of OBG per 30g of carbohydrates.

Consuming over 6g/day for at least four weeks may also significantly improve glycemic (blood sugar) control. OBG added to meals reduces blood sugar spikes, but outcomes depend on the dose and weight. While promising, further studies are needed to confirm long-term benefits, especially since oat processing may alter OBG's effectiveness.

What is oat milk?

Oat milk is made by blending oats with water and then straining the mixture to remove the pulp. The result is a naturally sweet drink due to the oat starches. After all, carbohydrates in their simplest form are broken down to glucose, which is sugar!

The question is - can the well-evidenced health benefits of eating oats (or OBG’s to be precise) be extrapolated and inferred to the consumption of oat milk?

When oat milk was first created for retail in 1999, a study showed that consuming oat milk over a 5-week period lowered total serum cholesterol and low-density lipoprotein cholesterol in men living with moderate hypercholesterolemia. This would be logical if these men were switching from dairy milk and lowering their saturated fat intake.

To elevate its nutritional profile and make it comparable to dairy milk, some brands may be fortified with vitamins and minerals, including vitaminD, B12 and calcium. However, not all are, so if these nutrients are missing from other areas of your diet, it’s worth checking the ones you buy.

Some brands of oat milk also contain oils, usually rapeseed or sunflower, as well as sugars, additives and emulsifiers, which brings us to the oil argument.

Seed oils in themselves are not inherently bad; the anti-seed oil police are not in cahoots with the anti-oat milk police! However, the raging seed oil debate is fuelling much of the current backlash against oat milk because the processing of seed oils at high temperatures in the manufacturing of ultra-processed foods can lead to lipid oxidation, which is believed to be inflammatory to the human body. It’s a complex topic there is a whole other article dedicated just to that if you want to understand more.

Finally, a recent study detected acrylamide and advanced glycation end products (AGES) in plant-based milks, including oats, which are formed due to high-heat processing methods. The EFSA regards acrylamide in foods as a public health concern, and research consistently links AGES with chronic disease. To put this into relatable terms, you may be consuming both of these compounds when you fry, bake or roast starch-based products.

Does oat milk spike blood sugar?

Confusing right? How can there be government-backed health claims about oats being blood sugar friendly when mainstream messaging is saying something totally different about oat milk?

The impact of oat processing may offer an explanation, a study on “healthy” humans demonstrated that the more processed the oat the lower the benefit conveyed on blood glucose and insulin responses. This finding is mirrored by the glycemic index (GI) of steel cut oats (52) vs rolled oats (57) vs quick oats (66) vs oat milk (69).

The GI measures carbohydrates on a scale of 1 to 100, indicating how much they raise blood sugar levels after eating. With oat milk on the cusp of being a high-GI food, it can be expected to spike your blood sugar, especially if you’re having a glass of oat milk on an empty stomach.

But blood sugar spikes have been taken out of context in recent times. Curiosity around health is a wonderful thing, but constantly worrying about spikes, which are a normal homeostatic response to the ingestion of carbohydrates, has led to unwarranted health anxiety in many.

However, the messaging can be contradictory for those with insulin resistance or type 2 diabetes. In clinical experience, we tend to find that what works best for supporting insulin sensitivity and balancing blood sugars is reducing the carbohydrates that will spike glucose, in line with the current research on low-carbohydrate diets, and this will often include oats.

So, is oat milk good for you?

This really depends on which brand you choose, how you use it and if you have any health conditions, which may mean an alternative milk is a better option.

If you are a latte lover, having 2 daily, from a brand containing rapeseed oil, could easily raise your fat intake by a whopping 14.4g, equivalent to approximately 130 kcal. At 1800 kcal a day, this is approximately 7% of daily calories. According to both USA and UK dietary guidelines, total fat should be no more than 35%.

In terms of nutritional density, obtaining those calories from whole-food sources of healthy fats such as nuts, seeds, oily fish, avocado, and cold-pressed olive and seed oils would deliver substantially higher levels of fibre, vitamins, minerals and antioxidants - rather than from oils in 2 cups of oat milk.

Although oat milk is higher in carbohydrates per 100ml than semi-skimmed milk, it is lower in naturally occurring sugars by approximately 45% and also lower in saturated fat. However, a 240ml cup can contain approximately 8.16g of sugar (albeit naturally occurring - just like milk). If you love a latte or a milky smoothie and can tolerate nuts, unsweetened almond milk would be a healthier option with no sugar.

Also, beware: If you have 4-5 cups a day and like a generous slug (100ml), you could easily consume 17g of sugar daily—just from oat milk!

The recommended daily intake is no more than 30g of sugar. So, if you are experiencing big energy dips in the day, feel tired or shaky after eating, or are having trouble shifting the pounds, you may want to look at your blood sugars and ditch the oat milk for a while. As a nutritional therapist working with people on their blood sugars and metabolic health, it isn’t the plant milk I’d recommend for this reason.

If, on the other hand, you are having an Americano with a dash of oat milk, then we need to add some common sense into this scenario. Similarly, if you are using oat milk in a smoothie and adding protein, fibre and healthy fats, you could mitigate the blood sugar impact to some degree.

As with all things nutrition, nothing is black and white and whether or not oat milk is a good choice for you will depend on your own goals and health status.

If you are going to opt for oat milk, choose a quality brand with minimal ingredients (e.g. just oats, water and sea salt - no, they don’t curdle). You may also want to check that it is glyphosate-free (some brands are) or organic, as oats are renowned for being heavily sprayed in farming, if in doubt, opt for organic brands. The levels in the oat milk may have past safety standards for consumption - but wouldn’t you rather avoid them if you can?

Food and drink preferences are unique to everybody, and the truth is there is no right or wrong answer for healthy individuals. However, if you have a chronic health condition that is impacted by food choices, such as type 2 diabetes or high cholesterol, and you are confused by the chaos of online advice, speak to a qualified nutritional therapist to help you make sense of the best way forward for your personal health needs.