Does milk take away the benefits of tea? The definitive scientific guide

January 13, 2026 •

4 min read

According to research published in the European Heart Journal, adding milk to black tea can completely blunt its beneficial effect on vascular function. But does milk take away the benefits of tea across the board, or is the answer more nuanced? This question has been a subject of scientific debate for decades, leaving many tea drinkers uncertain about their morning brew.

Quick Summary

Conflicting studies exist on whether milk reduces tea's benefits. The milk protein casein can bind with tea's antioxidants, potentially hindering their absorption. However, the impact varies by tea type, brewing time, and milk quantity. Flavor preferences and cultural traditions also play a significant role.

Key Points

Conflicting Evidence: There is conflicting scientific evidence on whether milk negates tea's health benefits, with some studies showing an inhibitory effect and others showing minimal impact.
Casein-Polyphenol Interaction: Milk proteins, especially casein, can bind to tea's antioxidant polyphenols (like catechins), which may reduce their bioavailability.
Blunted Vascular Benefits: At least one study found that adding milk to black tea completely blunted its beneficial effect on blood vessel function, a key cardiovascular benefit.
Delayed Absorption: Some evidence suggests that the milk-polyphenol binding may not destroy the antioxidants but rather delay their absorption, potentially freeing them later in the digestive process.
Taste vs. Health: The decision to add milk often comes down to personal taste and tradition, as milk can reduce the bitterness of tea.
Factors Matter: The impact of milk may depend on the type of tea (e.g., black vs. green), the quantity and fat content of the milk, and brewing time.
Milk Adds Nutrients: While potentially affecting tea's antioxidants, milk adds its own nutritional value, such as calcium and protein.

The Scientific Debate: Milk, Casein, and Catechins

For years, a central concern has revolved around the interaction between milk proteins, specifically casein, and the antioxidant compounds in tea, known as catechins and theaflavins. The hypothesis is that casein binds to these polyphenols, rendering them less bioavailable or active in the body. While this chemical interaction has been confirmed in lab settings, its real-world effect on human health has produced conflicting results across different studies.

The Evidence Against Milk

Multiple studies, both in-vitro and human, suggest that adding milk can dampen some of tea's most celebrated benefits. One study on 16 women found that black tea significantly improved blood vessel function, but adding skim milk completely nullified this effect. The researchers concluded that the milk protein casein was the likely culprit, binding to the flavonoids and preventing their action. Another in-vitro study found that adding skim milk to black, green, and white teas reduced their antioxidant activity. Furthermore, a review paper pointed out that reports on the negative effects of milk on antioxidant activity outnumber those showing neutral or positive effects.

The Conflicting Evidence and Nuances

However, other research complicates this straightforward conclusion. A smaller study on nine adults found that consuming black tea increased blood levels of antioxidant flavonoids, and adding milk did not inhibit this effect. Some researchers suggest that while casein does bind to polyphenols, it may only delay, not completely prevent, their absorption by the body. A study using in-vitro digestion models showed that while casein bound to catechins, it did not inhibit their anti-cancer activity on colon cells once digested. This suggests that the digestive process might eventually free the antioxidants, allowing them to be absorbed.

Differences in study design are also key to understanding the contradictory findings:

Tea Type: The effect of milk might vary depending on the tea. Some studies suggest green tea's benefits might be more sensitive to milk than black tea's.
Milk Type and Quantity: The amount and type of milk used can influence the outcome. Skim milk, with its higher protein concentration relative to fat, has been shown to have a more pronounced inhibitory effect than whole milk.
Brewing Method: A study noted that longer brewing times might lead to better absorption of antioxidants, regardless of milk addition.

The Broader Picture: Taste, Tradition, and Total Nutrition

For many, drinking tea is about flavor, comfort, and cultural tradition, not just maximizing antioxidant intake. Adding milk can reduce the astringency and bitterness of strong black teas, making them more palatable. From Indian chai to British breakfast tea, milk has long been a cherished addition.

Benefits of Milk in Tea

It's important to remember that milk itself offers nutritional benefits. A cup of milk tea provides:

Calcium and Vitamin D: Essential for bone health.
Protein: Contributes to satiety and muscle health.
Energy: Milk and optional sugar add calories, providing an energy boost.

Potential Downsides of Milk Tea

Conversely, overindulging in sweetened milk tea can have negative health consequences. High sugar content adds extra calories, potentially contributing to weight gain and increasing blood sugar. For individuals with lactose intolerance, milk tea can cause bloating and digestive discomfort. If you're drinking tea specifically for its cardiovascular benefits, particularly from black tea, consuming it plain appears to be the more effective option.

The Verdict: Weighing the Evidence

Ultimately, whether milk 'takes away' the benefits of tea depends on your priorities and perspective. For maximum antioxidant potency, drinking tea plain is the scientifically safer bet, particularly with black tea, which has been shown to have its vascular benefits blunted by milk. However, the impact is not a complete negation, and many factors influence the outcome. If you prioritize taste and enjoyment, adding milk in moderation is unlikely to erase all benefits, and milk brings its own nutritional value to the table. For those with heart health concerns, plain tea might be preferable. For most, the best advice is to enjoy tea however you like it, just be mindful of added sugars and your overall health goals. For a deeper dive into the science, check out this excellent overview from NutritionFacts.org.

Plain Tea vs. Milk Tea: A Comparative Analysis


Feature	Plain Tea (Black/Green)	Milk Tea	Findings & Implications
Antioxidant Capacity	Maximum	Reduced, variable	Milk proteins bind to polyphenols, potentially lowering antioxidant activity.
Vascular Function	Improved, particularly black tea	Blunted effect	Clinical study showed milk completely blocked black tea's benefit on blood vessel dilation.
Taste	Astringent, often bitter	Creamier, smoother, less bitter	Casein in milk interacts with tannins, reducing bitterness.
Cardiovascular Risk	Potentially reduced with regular intake	Less clear benefit	Milk's inhibitory effect on vascular function suggests less cardiovascular advantage compared to plain tea.
Nutritional Content	Antioxidants, hydration	Antioxidants, plus calcium, protein, and fat from milk	Milk adds bone-strengthening nutrients, but also potential calories and fat.
Weight Management	May aid metabolism	Potentially contributes to weight gain	Plain tea can boost metabolism, but adding sugar and milk increases calorie count.

Conclusion: Personal Choice is Key

The conversation around whether milk takes away the benefits of tea is more complex than a simple yes or no. The core scientific finding—that casein binds to tea's polyphenols—is not disputed, but its ultimate effect on the body is still debated. While some studies show a clear blunting of specific benefits like improved vascular function, others suggest the effects are minimal or temporary. Ultimately, if your primary goal is to maximize antioxidant absorption, drinking tea without milk is the most prudent path. However, for those who value tradition, flavor, and the added nutrients milk provides, the trade-off may be perfectly acceptable. As with all dietary choices, moderation and personal preference, guided by an understanding of the science, should inform your decision.

Frequently Asked Questions

The primary theory is that the protein in milk, known as casein, binds to the polyphenols (antioxidants) found in tea, such as catechins. This binding process can potentially inhibit their absorption and activity in the body.

The effect may differ between green and black tea. While studies have focused more on black tea, some evidence suggests that green tea's benefits might be more significantly reduced by milk. Differences in their primary antioxidant compounds (catechins in green tea vs. theaflavins in black) play a role.

No, you will likely still receive some benefits. The binding process does not appear to negate all antioxidant activity, and milk contributes its own nutrients like calcium and protein. The effect might simply be reduced or delayed compared to drinking plain tea.

Yes, studies suggest it does. Some research indicates that skim milk, with its higher protein content relative to fat, may have a stronger inhibitory effect on antioxidant capacity than whole milk. The quantity of milk added is also a factor.

Given the results of at least one study showing that milk blunted black tea's vascular benefits, it would be a safer choice for those focusing on cardiovascular health to drink their tea plain. However, consulting a doctor is always recommended for personalized advice.

Some research has indicated that proteins in soy milk can have a similar binding effect on tea's antioxidants as dairy milk. The impact of other plant-based milks like oat or almond on antioxidant bioavailability is less studied, so for maximum benefits, plain tea is best.

Adding milk is a long-standing cultural tradition rooted in flavor preference and taste. Milk can reduce the astringent, bitter taste of strong black teas, making them more enjoyable. In some cases, it was historically used to protect fine porcelain cups from cracking from hot tea.