The Big Brew: Does adding milk to tea take away benefits?

October 11, 2025 •

4 min read

Research has long explored the interactions between milk and tea, with one study showing that adding milk to black tea significantly blunted its ability to improve blood flow. This finding fuels a popular debate: Does adding milk to tea take away benefits? The answer is nuanced and depends on your health goals and how you prepare your brew.

Quick Summary

Milk proteins, particularly casein, can bind with tea's polyphenols, potentially reducing their antioxidant activity. While some studies suggest this interaction lessens certain cardiovascular benefits, others show conflicting results, indicating a variable effect. The overall impact is influenced by factors like the amount of milk and the type of tea used. Enjoying milk tea still provides nutrients like calcium, but minimizing milk can optimize antioxidant intake.

Key Points

Protein Interaction: Milk protein casein can bind to tea's polyphenols, potentially reducing their antioxidant bioavailability.
Conflicting Evidence: Some studies show a blunted effect on heart health when milk is added, while other research suggests a minimal impact or even conflicting results.
Nutrient Trade-offs: Adding milk provides beneficial nutrients like calcium and protein, but might slightly compromise the tea's antioxidant power.
Black vs. Green Tea: The impact of adding milk appears to be less clear for black tea compared to green tea, where it may more significantly inhibit metabolic benefits.
The Sugar Factor: The biggest nutritional concern often comes from added sugars and high-calorie syrups, which can negate tea's positive effects.
Personal Preference: For most people, the minor potential reduction in antioxidant effect from adding milk is outweighed by the enjoyment and nutritional value provided by the milk itself.

For centuries, people worldwide have enjoyed tea with milk, creating beloved traditions and comforting rituals. From the robust Indian chai to the classic British cuppa, the combination is a dietary staple. However, the scientific community has investigated whether this common practice compromises the health benefits associated with tea, particularly its high antioxidant content. The core of the issue lies in the molecular interaction between milk's proteins and tea's antioxidant compounds. Understanding this science helps clarify the controversy and allows you to make informed choices for your health.

The Science Behind Milk and Tea Antioxidants

The primary concern regarding adding milk to tea is the potential inhibition of the health-promoting effects of tea's polyphenols, such as catechins and theaflavins.

The Casein and Polyphenol Interaction

Dairy milk is rich in proteins, most notably casein. Studies suggest that casein and other milk proteins can bind with tea polyphenols. This binding can potentially reduce the bioavailability of these antioxidants, meaning the body's ability to absorb and utilize them is diminished.

Impact on Cardiovascular Benefits

One significant study involving human subjects found that plain black tea consumption led to an increase in blood flow and improved heart function by relaxing arteries. When skim milk was added, this beneficial cardiovascular effect was completely blunted. The researchers hypothesized that casein was the culprit, binding to the flavonoids and preventing their activity in the body. However, other studies have produced conflicting results, with some finding no significant effect on antioxidant levels in the blood.

What About Green Tea?

While most research has focused on black tea, the effects are also relevant to green tea. Green tea's catechins are theoretically susceptible to the same protein-binding interactions. One study showed that drinking green tea with milk reduced the tea's ability to boost calorie burning. This suggests that for maximum antioxidant potency, drinking green tea without milk is the safer bet.

Conflicting Research: It's Not a Simple Answer

The scientific evidence on this topic is far from conclusive. Several factors contribute to the varied findings across studies:

Methodology: The techniques used to measure antioxidant capacity (e.g., different lab assays) can produce different outcomes. Some assays might show a reduction in antioxidant activity in a test tube, while others might show an enhancement or a neutral effect.
Study Size: Many studies have been small, with limited participants, making it difficult to draw definitive conclusions.
Brewing Time: Some researchers have suggested that longer brewing times might increase the overall absorption of antioxidants, regardless of added milk.
Type of Milk: The composition of the milk matters. Some evidence suggests that skim milk, with a different protein-to-fat ratio, might have a more pronounced inhibitory effect than whole milk, though this requires further research.

Milk vs. Plain Tea: A Comparison


Feature	Tea with Milk	Plain Tea
Antioxidant Absorption	Potentially reduced, as casein can bind to polyphenols.	Maximum absorption of antioxidants like catechins and theaflavins.
Cardiovascular Impact	Some studies show blunted effects on blood vessel dilation.	Research supports potential improvements in blood flow and heart health.
Nutritional Additions	Provides essential nutrients like calcium, protein, and vitamin D.	Primarily provides benefits from tea compounds, with minimal added nutrients.
Flavor Profile	Smoother, less bitter, and less astringent, especially for strong black teas.	Can be more bitter or astringent, with the true, complex flavor of the tea leaves.
Calorie Count	Higher calorie count due to milk and often added sugar.	Naturally very low in calories, provided no sugar is added.

Making a Smarter Brew: Maximizing Benefits

For those who enjoy a daily milk tea, there are strategies to minimize potential drawbacks while still enjoying your ritual:

Choose the right tea: For black tea drinkers, the impact of milk is less clear than for green tea. Some teas, like Darjeeling or Earl Grey, are delicious without milk, offering a vibrant flavor profile.
Use plant-based alternatives: Soy milk and other plant-based options interact differently than dairy. While soy protein might also bind catechins, the overall effect and bioavailability can vary. For maximum antioxidant retention, opt for milks with a lower protein content or enjoy your tea without any additions.
Minimize added sugar: The biggest nutritional pitfall of many milk teas is the high sugar content. Avoid sugary syrups and sweetened condensed milk to keep the calorie count low and prevent spikes in blood sugar.
Focus on the ritual: The calming effects of a warm mug of tea can be stress-reducing, regardless of whether milk is added. For many, the mental and emotional benefits are just as important as the physical ones.

Conclusion: Personal Preference Reigns Supreme

So, does adding milk to tea take away benefits? The short answer is: possibly, but the effect is likely not absolute and depends on various factors. While milk proteins, especially casein, may bind to tea's polyphenols and reduce their antioxidant activity in some instances, this does not completely nullify the tea's benefits. The addition of milk also provides its own nutritional value, and for many, the improved flavor is worth any minor trade-off. Unless your primary goal is to maximize every last milligram of antioxidant from your tea, there is no need to abandon your milky brew. Ultimately, moderation is key, and enjoying your tea in a way that makes you feel good is the most important factor. For a more detailed look at the health implications, a review published in the journal Food Chemistry offers further insight into the polyphenol-protein interaction.

Authoritative Outbound Link

For more information on the complexities of the tea-milk interaction, you can consult research like the study published in the Journal of Photochemistry and Photobiology B: Biology, which details the effects of milk alpha-casein on tea polyphenols.

Frequently Asked Questions

Some studies suggest a reduction in benefits because the milk protein casein is believed to bind with tea's polyphenols, like catechins, potentially making them less available for the body to absorb and utilize for their antioxidant effects.

No, the effect is not the same. Most research has focused on black tea, but studies suggest the impact might be more significant for green tea, potentially inhibiting its metabolic benefits.

Yes, plant-based milk is an alternative, but its effect on tea's antioxidants can vary. Soy protein has also been shown to bind to catechins, similar to dairy casein, but other alternatives may interact differently. For maximum antioxidant intake, consuming tea plain is best.

No, adding milk does not completely negate all health benefits. While some antioxidant activity may be affected, tea still offers benefits like relaxation and improved digestion, and milk provides additional nutrients like calcium and protein.

The biggest health risk for many milk teas comes from the high amount of added sugar, not the milk itself. Excess sugar intake can lead to weight gain and an increased risk of type 2 diabetes.

The choice to switch to black tea depends on your personal health goals. If your primary aim is to maximize antioxidant absorption, drinking tea without milk is recommended. However, if you prefer the taste and also want the benefits of milk's calcium, enjoying your brew with milk is perfectly fine.

Yes, the amount of milk can matter. Using a smaller amount of milk will likely have less impact on the tea's antioxidant activity compared to using a large amount. This can be a good compromise for those who want a touch of creaminess without sacrificing too many potential benefits.

Yes, unsweetened or lightly sweetened milk tea is generally a healthier choice than soda. It provides antioxidants and potential vitamins, whereas soda is typically high in empty calories and sugar.