Understanding the Nutrition Diet: Why Shouldn't Milk Be Added to Tea?

October 12, 2025 •

3 min read

Adding milk to tea completely blunts the beneficial effect of tea on blood flow, according to a 2009 study on women who drank black tea. This critical finding is one of the main reasons why shouldn't milk be added to tea if maximizing its health benefits is the goal.

Quick Summary

Adding milk to tea can negatively affect its antioxidant properties and reduce its heart health benefits due to protein interactions. This combination can also introduce digestive issues, increase calories, and mask the tea's natural flavor, making plain tea a healthier option.

Key Points

Antioxidants are Reduced: Milk proteins bind to tea's polyphenols, inhibiting their absorption and potential health benefits.
Heart Health Impacted: Milk addition can prevent tea from improving blood vessel function.
Potential Digestive Issues: Milk tea may cause bloating, gas, acidity, or reflux, especially for individuals sensitive to lactose or with digestive issues.
Increased Calorie Count: Adding milk and sugar significantly increases calories, potentially hindering weight management.
Flavor Alteration: Milk can mask the subtle, complex flavors of quality tea.
Plain Tea Benefits: Drinking tea without milk or sugar is the best way to gain its full nutritional advantages.
Alternative Additions: Lemon or spices like ginger offer flavor without interfering with antioxidant absorption as much as milk might.

The Interaction Between Milk Proteins and Tea's Antioxidants

Tea contains antioxidants called polyphenols, including flavonoids. These compounds help protect the body from damage by combating free radicals. Milk contains proteins, such as casein, that can bind to these tea polyphenols. This binding forms complexes, potentially reducing the absorption and bioavailability of the beneficial antioxidants. The extent of this effect may vary depending on the type of milk used, with some research suggesting skimmed milk might have a stronger impact than whole milk.

Health Implications Beyond Antioxidants

The interaction between milk and tea can have several health consequences.

Cardiovascular Health

One study involving women who drank black tea found that plain tea improved blood flow and arterial function. However, adding milk eliminated this positive cardiovascular effect. Researchers believe casein protein is responsible for hindering tea's protective benefits.

Digestive Concerns

Milk tea can cause digestive issues, particularly for those who are lactose intolerant.

Bloating and gas: Can result from undigested lactose.
Acidity and heartburn: Drinking milk tea, especially on an empty stomach, may increase stomach acidity and lead to discomfort.
Constipation: The combination of caffeine and dairy may contribute to constipation in some individuals.

Weight Management and Calorie Content

Plain tea has minimal calories. However, adding milk and sugar significantly increases the calorie, fat, and sugar content, which can impact weight loss goals.

Flavor and Tradition

While historically milk was added to reduce bitterness, many tea drinkers feel milk masks the unique and complex flavors of quality tea leaves. Drinking tea plain allows for a fuller appreciation of its natural taste and aroma.

Black Tea vs. Milk Tea: A Comparative Look


Feature	Plain Black Tea	Milk Tea (with sugar)
Antioxidant Activity	High	Lowered by casein binding
Heart Health Effects	Improves blood vessel function	Effect is blunted
Calorie Content	Low	High
Digestive Impact	Can support digestion	Can cause bloating, acidity, or reflux
Flavor Profile	Complex and nuanced	Milder and often sweeter

What Are the Alternatives to Milk in Tea?

For those who prefer not to drink plain tea, alternatives exist:

Lemon: Adds a citrus flavor and may enhance antioxidant absorption.
Herbal additions: Spices like ginger or cardamom add flavor and may offer digestive benefits.
Plant-based milks: Options like almond or oat milk can be gentler on digestion for those with lactose intolerance. However, some plant proteins, like soy, may also interact with tea antioxidants.
Enjoying it black: The simplest way to maximize tea's health benefits is to drink it pure.

Conclusion

From a nutritional perspective, adding milk to tea is generally not recommended if the goal is to maximize the absorption of its beneficial antioxidants. Research indicates that milk can negate some of tea's positive effects, particularly on cardiovascular health. Additionally, milk tea can lead to digestive discomfort and increased calorie intake. While cultural preferences and taste play a significant role, understanding why shouldn't milk be added to tea highlights the potential trade-offs in health benefits.

For a detailed scientific explanation of how milk proteins interfere with tea antioxidants, a relevant review article is available in the Critical Reviews in Food Science and Nutrition.

Frequently Asked Questions

Adding milk to tea doesn't completely destroy antioxidants, but the proteins in milk can bind to them, making it harder for the body to absorb and utilize them effectively.

Milk tea can be problematic for digestion, particularly for those with lactose intolerance. It may cause bloating, gas, increased acidity, and reflux.

Milk proteins interact with tea's beneficial compounds, preventing the tea from improving blood vessel function, a positive effect observed with plain black tea consumption.

Yes, alternatives include a squeeze of lemon, which might boost antioxidant absorption, or spices like ginger or cardamom for added flavor.

Some research suggests skimmed milk, with a higher protein-to-fat ratio, might reduce tea's antioxidant capacity more than whole milk.

While studies often focus on black and green tea, the interaction between proteins and polyphenols is likely relevant to other teas from the Camellia sinensis plant, though the degree may differ.

Drinking milk tea in moderation is a personal choice. However, it's helpful to be aware of the potential reduction in antioxidant benefits and the added calories.

Yes, especially if sugar is added. The extra calories, fat, and sugar from milk and sweeteners can contribute to weight gain over time.

Interestingly, adding milk may reduce tea's ability to stain teeth because casein protein binds to staining tannins.