Tea is one of the most popular beverages in the world, and drinking it is thought to provide various health benefits.

In Great Britain and some other parts of the world, tea is commonly consumed with milk.

However, it’s unclear whether adding milk to tea provides additional benefits — or instead interferes with the activity of tea compounds in your body.

This article provides an overview of the effects of adding milk to tea.

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Both tea and milk provide benefits

While several kinds of tea may provide health benefits, green and black teas are the most researched.

Both are made from the leaves of the Camellia sinensis plant but undergo different processing methods (1).

Green and black teas are rich in plant compounds called flavonoids. These compounds act as antioxidants to help fight underlying cell damage caused by reactive molecules known as free radicals. High levels of free radicals contribute to heart disease, cancer, and other issues (1, 2).

Specifically, green teas are rich in flavonoids called catechins, while black teas have high amounts of theaflavins (3).

Due to these compounds, drinking green and black tea has been associated with lower blood pressure, anticancer effects, and reduced cholesterol levels in both animal and human studies (4, 5, 6, 7).

On the other hand, milk is rich in nutrients, such as protein, calcium, and potassium, that are vital for optimal growth, body composition, and bone health (8, 9).

summary

Teas, especially green and black varieties, contain antioxidant compounds that may boost heart health and exert anticancer effects. Meanwhile, milk is rich in beneficial nutrients that contribute to growth and bone health.

Milk proteins may interfere with tea compounds, but research is mixed

Given that both tea and milk contain health-promoting compounds and nutrients, combing the two may seem beneficial.

In fact, one study in over 1,800 adults in China found that both tea and milk consumption were independently linked to a lower risk of oral cancer and that they may have a particularly beneficial effect when consumed together (10).

Yet, some studies suggest that the proteins in milk may interfere with the absorption and antioxidant activity of the compounds tea (11).

One study in 16 adult women observed that drinking 2 cups (500 ml) of plain black tea significantly increased blood flow, which can help improve heart function, compared with drinking water. Meanwhile, drinking black tea with skim milk did not have these effects (11).

The researchers concluded that casein, a type of protein in milk, may bind to flavonoids in tea and prevent their activity in the body (11).

However, another small study in 9 adults noted that consuming black tea increased blood levels of antioxidant flavonoids and that adding milk to tea did not inhibit this effect (12).

Interestingly, the researchers suggested that longer brewing times may lead to better absorption of the antioxidants in tea, regardless of the addition of milk (12).

Based on the conflicting results of these studies, milk may interfere with the activity of antioxidants in teas to some extent, but it may not have the same effect with teas that have been infused for long periods.

However, more research is needed to better understand the potential benefits and downsides of adding milk to tea.

summary

Limited research suggests that adding milk to tea may interfere with the activity and absorption of antioxidant compounds, while other studies suggest the opposite.

The type of tea may make a difference

The effect of adding milk to tea may also depend on the type of tea, but the few studies on this topic have mostly focused on black tea.

Since green teas are also rich in flavonoids, milk may theoretically affect the compounds in green tea similarly to how it affects the compounds in black tea.

In fact, one study in 18 adults found that drinking milk with green tea capsules inhibited the boost in the number of calories burned that typically results from taking green tea capsules alone (13).

While these results are interesting, more research is needed to better understand the effect of combining milk with green tea rather than green tea supplements.

What’s more, no studies have analyzed the effects of adding milk to teas other than black and green varieties.

summary

Milk’s effects on the benefits of tea may depend on the type of tea, but most studies have focused on the effects of adding milk to black and green teas.

The bottom line

Tea, especially black and green varieties, is rich in compounds that act as antioxidants and may help lower blood pressure and cholesterol levels, among other benefits.

Some studies suggest that adding milk to tea may inhibit the activity of these compounds, while others have observed the opposite effect.

Additionally, most of the studies on milk and tea consumption include small sample sizes and have not included participants who regularly drink tea with milk over long periods.

Thus, it’s unclear whether combining milk and tea is beneficial, although consuming tea in general has been more clearly linked to potential benefits.