Lemon or milk?

Apparently adding milk to black tea eliminates its heart disease and stroke fighting abilities, a very good reason not to:

Drinking tea can reduce the risk of heart disease and stroke but only if milk is not added to the brew, German scientists said Tuesday.

Research has shown that tea improves blood flow and the ability of the arteries to relax but researchers at the Charite Hospital at the University of Berlin, Germany, found milk eliminates the protective effect against cardiovascular disease.

"The beneficial effects of drinking black tea are completely prevented by the addition of milk, said Dr. Verena Stangl, a cardiologist at the hospital.

"If you want to drink tea to have the beneficial health effects you have to drink it without milk. That is clearly shown by our experiments," she told Reuters.
[...]
Stangl and her team discovered that proteins called caseins in milk decrease the amount of compounds in tea known as catechins which increase its protection against heart disease.

They believe their findings, which are reported in the European Heart Journal, could explain why countries such as Britain, where tea is regularly consumed with milk, have not shown a decreased risk of heart disease and stroke from drinking tea.