Tea has long been considered a drink beneficial for the cardiovascular system and the prevention of a number of diseases. However, recent studies show that adding milk may negate the beneficial effects of tea. German scientists studying the effects of tea on blood vessels concluded that milk proteins alter the biological activity of the beneficial components of the drink.

The main active ingredients in tea—flavonoids, or catechins—promote the dilation of blood vessels, improving blood flow and reducing stress on the heart. An experiment involving 16 female volunteers showed that black tea without milk effectively dilated arteries for two hours after consumption. When milk was added, this effect completely disappeared, indicating the blocking action of casein, a protein found in milk.

These results were also confirmed in animal experiments. Rats given tea with milk showed no improvement in vascular function, while those drinking tea without additives showed positive changes. This discovery helps explain why, despite widespread tea consumption, countries traditionally drinking tea with milk, such as the UK, have high rates of cardiovascular disease.

Scientists note that milk's effect extends beyond the cardiovascular system to tea's potential anticancer properties. The interaction of casein with catechins reduces their biological activity, which may reduce the beverage's preventive effect against certain types of cancer. Therefore, periodic consumption of tea without milk may be particularly beneficial for health.

Experts also emphasize that tea is only part of a comprehensive heart care program. Regular exercise, quitting smoking, and a balanced diet remain more effective measures for preventing cardiovascular disease. However, choosing tea without milk can enhance the beverage's positive effects on blood vessels and overall well-being.

Finally, the psychological aspect of tea consumption is no less important. Even a cup of tea with milk can promote relaxation and reduce stress, which has a positive effect on heart function. However, for maximum heart protection, it is worth giving preference to tea without additives, allowing the body to fully utilize its biologically active substances.