Image Credit: Pixabay. This image has been modified.

What Happens if You Add Milk to Tea?

Our endothelium, the inner lining of our blood vessels that controls the function of every artery in our body, “appears to play a critical role in a variety of human disorders, including peripheral vascular disease, stroke, heart disease, diabetes, insulin resistance, chronic kidney failure, [cancer, and blood clots]….” Unfortunately, endothelial cells only live about 30 years, and their replacements don’t seem to function as well. So, “[a]s men and women approach the ages of 40 and 50, there is a progressive decline in endothelial function.” At age 50 or 60, we “can no longer tolerate this risk-factor burden that [we] were once able to tolerate at age 10 or 20,” thanks to this progressive decline in endothelial function.

Or, at least, that’s what we used to think.

As I discuss in my video Tea and Artery Function, there are increasing data to suggest that age is not an immutable risk factor—the decline in artery function is not just an inevitable consequence of aging Researchers did not see the same progressive decline in a Chinese population studied. The older Chinese people in their 60s had the arterial function of young folks in their 20s. “These data suggest that progressive endothelial dysfunction is not an inevitable consequence of aging but might be related to prolonged exposure to environmental factors more prevalent in westernized countries than in China.” What could it be? Traditional Chinese diets include green tea, which has been shown to have a beneficial effect on endothelial function within 30 minutes of consumption, lasting about two hours. It wasn’t the caffeine, which alone had no effect. They suspect it was the flavonoid phytonutrients in the leaves.

Black tea appears to work about just as well as green tea, but then why is green tea associated with lower heart disease risk while black tea is not? In fact, in two British studies, tea consumption was associated with an increased risk of coronary artery disease. Maybe it’s because the Brits commonly drink their tea with milk, whereas green tea is typically drank straight? If only there were a country that drank black tea, but without milk. There is. The Netherlands. In those studies, black tea was associated with the same drop in risk as the green tea studies. So, maybe it is the milk. But you can’t really know until you put it to the test.

Researchers found the “addition of milk to black tea completely prevents the biological activity of tea in terms of improvement of endothelial function.” So, that could explain it. It appears the milk protein casein is the culprit, though soy protein was recently found to have the same nutrient binding effect. The European Society of Cardiology issued a press release about the study showing the protective effect of tea “is totally wiped out by adding milk” and suggested consumers should consider cutting down. Milk-drinkers were not amused: “As long as the reported results are not confirmed in a fair number of humans who drink their tea outside the lab setting, we will continue to add milk to ours.” The researchers responded, challenging the notion that their study wasn’t big enough. They had 16 subjects, and the results were highly significant. Across those 16 people, the “addition of milk to tea not only reduced, but completely blunted the effects of tea….The rationale for drinking tea in a lab setting was that only under these conditions could the influence of other beverages and food be controlled for.” They were doing an experiment after all. Were they supposed to drag the equipment to a Starbucks or something?

“As doctors,” the milky tea drinkers asserted, “we would not prescribe a new drug to patients if it was studied only in one small study. In analogy, milk abstinence should not be recommended to tea drinkers…” They apparently were forgetting that the reason we don’t prescribe drugs without overwhelming evidence is that drugs can kill. So the benefits better outweigh the risks, but what’s the downside of a little milk abstinence?


If this is what one plant can do, imagine the effects of a whole diet centered around plant foods. That’s the subject of my video Plant-Based Diets and Artery Function.

Do be careful about green tea from China if you eat the leaves, though. See Lead Contamination of Tea.

I answer other questions you may have about tea in these videos:

In health,
Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live, year-in-review presentations:

Comenta

Michael Greger M.D., FACLM

Michael Greger, M.D. FACLM, is a physician, New York Times bestselling author, and internationally recognized professional speaker on a number of important public health issues. Dr. Greger has lectured at the Conference on World Affairs, the National Institutes of Health, and the International Bird Flu Summit, testified before Congress, appeared on The Dr. Oz Show and The Colbert Report, and was invited as an expert witness in defense of Oprah Winfrey at the infamous "meat defamation" trial.


Comment Etiquette

On NutritionFacts.org, you'll find a vibrant community of nutrition enthusiasts, health professionals, and many knowledgeable users seeking to discover the healthiest diet to eat for themselves and their families. As always, our goal is to foster conversations that are insightful, engaging, and most of all, helpful – from the nutrition beginners to the experts in our community.

To do this we need your help, so here are some basic guidelines to get you started.

The Short List

To help maintain and foster a welcoming atmosphere in our comments, please refrain from rude comments, name-calling, and responding to posts that break the rules (see our full Community Guidelines for more details). We will remove any posts in violation of our rules when we see it, which will, unfortunately, include any nicer comments that may have been made in response.

Be respectful and help out our staff and volunteer health supporters by actively not replying to comments that are breaking the rules. Instead, please flag or report them by submitting a ticket to our help desk. NutritionFacts.org is made up of an incredible staff and many dedicated volunteers that work hard to ensure that the comments section runs smoothly and we spend a great deal of time reading comments from our community members.

Have a correction or suggestion for video or blog? Please contact us to let us know. Submitting a correction this way will result in a quicker fix than commenting on a thread with a suggestion or correction.

View the Full Community Guidelines

Deja una respuesta

Tu correo electrónico no se publicará Los campos obligatorios están marcados *

Pin It en Pinterest

Share This