What Happens When You Drink Oat Milk Daily

Oat milk has become a pantry staple for many people seeking a plant-based alternative to dairy. It’s creamy, dairy-free, and often enriched with nutrients like calcium and vitamin D. But like any food, drinking oat milk every day may come with some downsides especially depending on how it’s made and how your body responds.

Here are seven potential side effects to keep in mind if oat milk is part of your daily routine.

1. Allergic Reactions

Although rare, oat allergies do exist. If you're allergic, symptoms might include:

• Itchy skin or rashes

• Digestive upset

• In rare cases, anaphylaxis, a serious reaction involving difficulty breathing

You may also react to certain additives, such as xanthan gum or emulsifiers, which are used to stabilize many commercial oat milk brands.

2. Bloating and Digestive Issues

Oats are generally considered gut-friendly and are a source of prebiotics, which help support healthy gut bacteria. But oat milk’s high fiber content or emulsifiers may trigger:

• Bloating

• Gas

• Indigestion

Some people with celiac disease may also react to avenin, a protein found in oats that’s structurally similar to gluten.

3. Added Sugars

Many flavored or sweetened oat milks contain added sugar, which can lead to:

• Weight gain

• Increased risk of type 2 diabetes

• Higher risk of heart disease

• Dental problems

The American Heart Association recommends keeping added sugar to no more than 25 grams per day for women and 36 grams for men. Be sure to read the label and opt for unsweetened varieties when possible.

4. High in Carbohydrates

Oat milk is naturally higher in complex carbohydrates, which can provide lasting energy but it’s important to watch your intake if you’re monitoring blood sugar or following a low-carb diet.

The glycemic index (GI) of oat milk ranges from 49–69 (medium), and its glycemic load (GL) is between 12–17, depending on the brand. In comparison, cow's milk has a much lower GI and GL.

This doesn’t make oat milk bad, but if you drink it frequently or in large amounts, it could affect blood sugar especially for people with insulin resistance or diabetes.

5. Gluten and Soy Cross-Contamination

While oats are naturally gluten-free, oat milk is often processed in shared facilities, making cross-contamination with gluten or soy a risk. This can be a concern for people with:

• Celiac disease

• Non-celiac gluten sensitivity

• Soy allergies

To stay safe, look for certified gluten-free oat milk and check product labels for soy exposure.

6. Risk from Additives and Preservatives

Some oat milks include vegetable oils, thickeners, or phosphate-based stabilizers (like dipotassium phosphate), which may raise concerns for people with heart disease, kidney conditions, or those on a low-sodium diet.

Certain additives may:

• Affect bone health in people with kidney disease

• Disrupt gut microbiota over time (especially emulsifiers, though more research is needed)

If you're aiming for a clean-label option, look for oat milk with minimal ingredients: water, oats, and salt are usually enough.

7. Not Suitable for Infants or as a Cow’s Milk Substitute

Oat milk lacks the protein, fat, and micronutrients needed for infants under 12 months and is not recommended as a primary milk source for toddlers unless part of a balanced diet.

For children over one year, oat milk can be part of a nutritious diet but should not completely replace breast milk, formula, or cow’s milk without input from a healthcare provider.

How Much Is Too Much?

Oat milk can absolutely be part of a healthy, balanced diet especially if you:

• Tolerate oats well

• Choose unsweetened and fortified varieties

• Use it alongside a variety of nutrient-rich foods

However, be mindful of how much you’re drinking, especially if you're concerned about added sugar, blood sugar control, or digestive health.

According to recent data, about 1 in 5 plant-based milk products contains added sugar.¹ Choosing a cleaner-label version or making your own oat milk at home can be a great way to avoid unnecessary ingredients.

Key Takeaways

• Oat milk is generally safe and nutritious but can cause digestive issues or blood sugar spikes in some people.

• Always check the label for added sugars, emulsifiers, and potential gluten or soy exposure.

• If you’re drinking oat milk daily, balance it with other sources of protein, healthy fats, and whole foods.

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