THE FACTS

Really? Anahad O’Connor tackles health myths.

Next to water, tea is the most widely consumed beverage in the world. Chock-full of antioxidants, vitamins and other compounds, tea has been linked in a variety of studies to stronger immune function and reduced cell damage. Some research suggests tea may prevent cavities, improve blood sugar levels and perhaps provide cardiovascular benefits.

In many parts of the world, the custom is to serve tea with milk. But lately researchers have been surprised to find that adding milk may strip tea of some of its beneficial effects.

In a study published in The European Heart Journal, researchers had 16 healthy adults drink cups of freshly brewed black tea, black tea mixed with a small amount of skim milk, or boiled water. Then the scientists measured the effects on vascular function.

Compared with water, black tea “significantly improved” arterial function, the researchers found, “whereas addition of milk completely blunted the effects of tea.”

The scientists repeated similar tests in mice and found the same results, which they speculated may be a result of proteins in milk binding to and neutralizing antioxidants. “Milk,” the researchers wrote, “counteracts the favorable health effects of tea on vascular function.”

A study published this year looked at whether the effect was limited to dairy products. It was not: Proteins in soy milk had the same effect as regular milk on antioxidants in tea.

THE BOTTOM LINE

Adding milk to tea may reduce some of its healthful properties, studies show.