Does adding oat milk to green tea reduce benefits?

January 2, 2026 •

4 min read

While some studies have shown that cow's milk proteins can bind to green tea's antioxidants and slightly diminish their absorption, plant-based options like oat milk behave differently. This article explores the science behind whether adding oat milk to green tea reduces benefits and how you can still enjoy a nutritious beverage.

Quick Summary

Adding oat milk to green tea can cause a minor reduction in antioxidant activity due to polyphenol interactions with fiber, but the effect is less than with dairy. It remains a very healthy drink.

Key Points

Minor Antioxidant Reduction: Adding oat milk can cause a small reduction in green tea's antioxidant activity due to interactions between polyphenols and oat fiber.
Less Impact Than Dairy: The reduction in antioxidant benefits is less significant than when using cow's milk, which contains casein proteins that bind more strongly to catechins.
Still a Healthy Drink: Green tea with oat milk remains a nutritious beverage, offering antioxidants and other benefits from both ingredients.
Influence of Fat Content: Research shows that the fat content of oat milk can influence the bioaccessibility of tea polyphenols during digestion, with higher fat content sometimes yielding higher bioaccessibility at certain concentrations.
Tips to Maximize Benefits: For maximum antioxidant intake, prepare tea with hot water first, add oat milk after it cools slightly, and consider using a smaller quantity of oat milk.
EGCG Remains Bioactive: While absorption can be slightly affected, studies suggest that EGCG remains largely bioactive even with milk alternatives.
Flavor vs. Purity: The choice ultimately balances the desire for creamy flavor with the goal of maximizing the tea's potent, unadulterated benefits.

The Science Behind Green Tea's Benefits

Green tea is renowned for its high concentration of powerful antioxidants known as catechins, with the most potent being epigallocatechin gallate (EGCG). EGCG is the main compound responsible for green tea's various health benefits, including its anti-inflammatory, antioxidant, and potential metabolism-boosting properties. These benefits are what many seek when consuming green tea. The concern arises from the potential interaction of these delicate compounds with other ingredients.

The Problem with Dairy Milk

For years, a popular debate has centered on adding milk to green tea. The proteins in cow's milk, particularly casein, are known to bind with tea's catechins. This binding process can slightly reduce the antioxidant activity and overall bioavailability of these compounds, meaning the body absorbs less of them. Although the effect is not a complete elimination of benefits, it is a factor for those aiming to maximize their nutrient intake from green tea.

How Oat Milk Compares

Unlike cow's milk, oat milk does not contain casein protein. This difference is significant. A study comparing various milk types found that cow's milk had the most pronounced negative effect on antioxidant activity, followed by soy milk, which is also higher in protein. Oat, almond, and coconut milks showed less interference. This suggests that oat milk is a safer choice for preserving green tea's benefits, though not entirely without interaction. The minor interference that does occur is primarily due to the interaction between green tea polyphenols and the soluble fiber in oat milk, known as beta-glucan.

The Polyphenol-Beta-Glucan Interaction

Research has explored the interaction between EGCG and oat β-glucan. It was found that EGCG can be adsorbed by oat β-glucan through non-covalent interactions like hydrogen bonding. This binding can affect the bioaccessibility of the polyphenols, meaning their availability for absorption in the small intestine can be reduced. However, the extent of this reduction is dependent on factors such as the concentration of both the tea extract and the oat milk's fat content. For example, a 3.0% fat oat milk system exhibited higher polyphenol bioaccessibility than a 1.5% fat version.

A Comparison of Oat Milk vs. Cow's Milk Impact on Green Tea

To better understand the differences, here is a comparison table outlining the impact of adding oat milk versus cow's milk to your green tea.


Feature	Oat Milk Impact	Cow's Milk Impact	Rationale & Source
Antioxidant Binding	Minor binding occurs with beta-glucan, resulting in a less significant reduction of catechins compared to dairy.	Strong binding occurs between casein protein and catechins, which significantly reduces antioxidant activity.	Casein protein binds more readily to polyphenols than oat β-glucan.
EGCG Bioavailability	Slight reduction, depending on fat content and tea concentration. Some studies show EGCG bioavailability can still be high.	Reduces EGCG bioavailability more significantly due to stronger protein binding.	Cow's milk contains a higher concentration of proteins that interfere with catechin absorption.
Overall Health	Remains a very healthy beverage, providing antioxidants, fiber from oats, and often fortified vitamins.	Still healthy, but with a more notable decrease in the bioavailability of the tea's key antioxidants.	The overall benefits of green tea outweigh the minor effects of adding milk.
Nutrient Absorption	Does not interfere with iron absorption like cow's milk might, as it lacks calcium.	Calcium can interfere with the absorption of iron found in green tea.	Calcium competes with iron for absorption in the body.

How to Maximize Green Tea Benefits with Oat Milk

For those who prefer a creamy green tea but want to minimize any potential reduction in benefits, there are several strategies you can employ:

Steep First, Add Later: Prepare your green tea or matcha with hot water first. Allow it to steep and cool slightly before adding your oat milk. High heat can sometimes degrade beneficial compounds.
Choose Lower-Fat Oat Milk: Some research suggests that oat milk with lower fat levels may bind more easily with polyphenols. However, another study found higher bioaccessibility in a 3% fat version, though this may relate more to emulsion stability. For general purposes, using less overall oat milk will reduce potential interactions.
Use Less Oat Milk: The amount of milk added matters. A smaller ratio of oat milk to tea will naturally result in less interaction with the tea's compounds.
Time It Right: Consider drinking pure green tea on its own for a concentrated dose of antioxidants, and save the oat milk version for when you crave a creamier texture. A 2011 study on thermogenesis found that green tea with milk had no effect on the resting metabolic rate, while green tea alone did.

Conclusion: A Healthy Compromise

Ultimately, the choice to add oat milk to green tea is a healthy and personal one. While there is a scientifically recognized, albeit minor, interaction between oat milk's components and green tea's antioxidants, it is significantly less impactful than the interaction with traditional dairy milk due to the absence of casein. For most consumers, the difference is negligible compared to the flavor and texture preference it provides. Green tea with oat milk remains a nutrient-rich beverage packed with antioxidants, fiber, and other beneficial compounds. By following a few simple steps, you can minimize any potential reduction in benefits and confidently enjoy your creamy, delicious green tea latte. The key is balance and moderation.

For more in-depth information, you can consult research on EGCG adsorption: Adsorption of (–)-epigallocatechin-3-gallate (EGCG) onto oat β-glucan.

Frequently Asked Questions

Yes, green tea with oat milk is still a healthy beverage. While some of the tea's antioxidant activity may be slightly reduced, the overall nutritional benefits from both the green tea and the fortified oat milk remain significant.

Oat milk can sometimes curdle when added to hot green tea, especially if the tea is very acidic or hot. Using a barista-style oat milk, warming the milk gently before adding it, and allowing the tea to cool slightly can prevent curdling.

Yes, it is perfectly fine to drink matcha with oat milk. Matcha contains very high levels of EGCG, and while oat milk may slightly reduce absorption, the health benefits still outweigh any minimal interference.

To maximize antioxidant intake, steep your green tea or matcha in hot water first. Let it cool for a few minutes before adding your oat milk. Using a smaller amount of oat milk can also help.

Yes, from an antioxidant absorption standpoint, oat milk is a better choice. The casein protein in cow's milk binds more strongly to green tea catechins and reduces their activity more significantly than oat milk's components.

Yes, the order and timing of preparation can matter. Steep the tea first to extract the catechins fully, and then add the milk. High heat can potentially degrade some compounds, so letting the tea cool slightly is also beneficial.

EGCG (Epigallocatechin gallate) is the most abundant and potent antioxidant in green tea. Its interaction with proteins (like casein) and fibers (like oat β-glucan) is important because it can affect the compound's bioavailability, or how much of it is absorbed by the body.