Good heavens, no!
Adulterate an excellent cup of tea?!
Except, of course, a lot of people—perfectly fine people, friends of mine even—prefer to add milk to their tea.
And they are certainly entitled to do this.
But can I use science to support my strict No-Milk policy?
Well, like most things, answers are neither clear-cut nor simple.
That’s mostly because tea is pretty complicated. First, you have endless varieties of black and white and green and oolong tea, which means you aren’t necessarily comparing apples to apples.
Consider, for instance, those beneficial polyphenols—the reason that many of us drink tea. In green tea, these largely remain as flavanols or catechins (simple polyphenols).
To produce black tea, however, the leaves are more fully oxidized, which converts the simple polyphenols into more complex forms (theaflavin, which provides the bright taste, and thearubigin, which contributes complexity). While the green tea catechins and the black tea theaflavins seem to retain the same antioxidant potency (Leung et al. 2001), the complexity of the black tea components complicates research studies.
This means that the physiological effects of drinking black tea are more difficult to tease out. And milk is generally added to black tea, not green.
Some of the science of milk in tea:
One team of researchers studied how drinking hot caffeinated beverages affects our physiological response and mood—and how milk might change that response.
Among their results, they found that milk added to black tea or coffee had an impact only while the beverage was being consumed (Quinlan et al. 1997:171).
These effects included mitigating the increased heart rate and skin conductance that comes with drinking tea and coffee.
Milk didn’t seem to change the bioavailability of caffeine, and the presence of milk seemed similar to that of caffeine (Quinlan et al. 1997:172), improving mood for instance—though the authors note that this may because the people in this study said that they preferred milk in their tea or coffee!
(Yes, drinking something the way I like it would improve my mood and perhaps affect my heart rate!)
Quinlan and colleagues point out that because the addition of milk did not have lasting physiological effects, these effects may be “part of a sensory response, with milk perhaps reducing the sensory impact (e.g., bitterness) of the beverages in the mouth” (Quinlan et al. 1997:171).
Ummm, when you are doing a study on people who said at the outset “that they habitually consumed tea/coffee with milk” (Quinlan et al. 1997:165), some of these results seem a bit obvious.
But anyway, if you like milk in your tea, fine. Milk apparently doesn’t change the health benefits of drinking tea in any substantial way.
And it will make you happier if tea with milk is your cup of tea!
–Leung, L. K., et al. “Theaflavins in black tea and catechins in green tea are equally effective antioxidants,” Journal of Nutrition 131(9):2248–51. 2001.
–Quinlan, P., J. Lane, and L. Aspinall. “Effects of hot tea, coffee and water ingestion on physiological responses and mood: The role of caffeine, water and beverage type,” Psychopharmacology 134:164–173. 1997.