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:

How to Reverse Type 2 Diabetes

 

Diabetes reversal, not just treatment, should be a goal in the management of type 2 diabetes. Type 2 diabetes can be reversed not only with an extremely low calorie diet, but it can  also be reversed with an extremely healthy diet. Could it be because an extremely healthy diet is also low in calories? This is the topic of my video Diabetes Reversal: Is It the Calories or the Food 

Study subjects lost as much weight on a green, leafy vegetable-packed plant-based diet as those who were on a semi-starvation diet based on liquid meal replacements. So, does it matter what we’re eating as long as we’re eating few enough calories to lose 15 pounds a month?

Even if diabetes reversal is just about calorie restriction, instead of subsisting off largely sugar, powdered milk, corn syrup, and oil (common ingredients in some liquid diet drinks) on the plant-based diet at least one can real food—in fact, as many low-cal veggies as desired. So, even if it only works because it’s just another type of calorie-restricted diet, it’s certainly a healthier version. But, even participants in the study who did not lose weight—or even gained weight eating enormous quantities of whole healthy plant foods—appeared to improve their diabetes. Thus, the beneficial effects of this kind of diet appear to extend beyond weight loss.

The successful treatment of type 2 diabetes with a plant-based diet goes back to the 1930s, providing “incontestable evidence” that a diet centered around vegetables, fruits, grains, and beans was more effective in controlling diabetes than any other dietary treatment. In a randomized controlled trial, insulin needs were cut in half and a quarter of the subjects ended up off insulin altogether. But, again, this was a low-calorie diet. Walter Kempner at Duke University School of Medicine reported similar results 20 years later with his rice and fruit diet studies, showing for the first time documented reversal of diabetic retinopathy in a quarter of his patients, something never even thought possible. One patient, for example, was a 60-year-old diabetic woman already blind in one eye and who could only see contours of large objects with the other. Five years later, while on the diet, instead of her vision getting worse, it got better. She “could make out faces and read signs and large newspaper print,” and got off insulin, had normal blood sugars, and had a 100-point drop in her cholesterol. Another patient went from only being able to read big headlines to being able to read newsprint four months later. What was behind these remarkable reversals? Was it because the diet was extremely low-fat or because there was no animal protein or animal fat? Or, was it because the diet was so restrictive and monotonous that the patients lost weight and improved their diabetes that way?

To tease this out, we needed a study where researchers switched people to a healthy diet, but forced them to eat so much they didn’t lose any weight. Then, we could see if a plant-based diet has unique benefits independent of all the weight loss. For that, we had to wait another 20 years until a study in the 1970s. In it, diets were designed to be weight-maintaining. Participants were weighed every day, and, if they started losing weight, the researchers made them eat more food—in fact, so much food that some of the participants had trouble eating it all, but they eventually adapted. Thus, there were no significant alterations in body weight despite restrictions of meat, dairy, eggs and processed junk, and there were enough whole plant foods—whole grains, beans, vegetables, and fruit—to provide 65 grams of fiber a day, four times what the Standard American Diet provides.

The control diet they used was the conventional diabetic diet, which actually had nearly twice the fiber content of the Standard American Diet, so it was probably healthier than what they had been used to eating. So, how did the even healthier diet group do? With zero weight loss, did the dietary intervention still help? The study compared the number of units of insulin with which subjects had to inject themselves daily before and after going on the plant-based diet. Overall, despite no change in weight, insulin requirements were cut about 60 percent, and half of the diabetics  were able to get off insulin altogether. Was this after five years, or after seven months, as had been the case in the other studies discussed above? No.

It was after 16 days.

To be clear, we’re talking about diabetics who had had diabetes as long as 20 years, injecting 20 units of insulin a day, getting off insulin altogether in as few as 13 days, thanks to less than two weeks on a plant-based diet. Patient 15, for example, had injected 32 units of insulin while on the control diet, and then, 18 days later, none. Lower blood sugars on 32 units less insulin.

That’s the power of plants.

As a bonus, their cholesterol dropped like a rock to under 150 on average in 16 days, making them nearly heart attack proof as well. Just as “moderate changes in diet usually result in only modest reductions” in cholesterol, asking people with diabetes to make moderate changes often achieves equally moderate results, which is one possible reason why most end up on oral drugs, injections, or both. Everything in moderation may be a truer statement than people realize. Moderate changes in diet can leave one with moderate blindness, moderate kidney failure, moderate amputations. Moderation in all things is not necessarily a good thing.

The more we, as physicians, ask from our patients, the more we—and they—get. The old adage, “shoot for the moon,” seems to apply. It “may be more effective than limiting patients to small steps that may sound more manageable but are not sufficient to actually prevent disease progression.”


Although I have dozens of videos about diabetes, I think Diabetes Reversal: Is It the Calories or the Food may be the single most powerful one I‘ve made. Please share this life-changing, life-saving video with anyone you know who has type 2 diabetes or is at risk for the dreaded disease. As far as I’m concerned, it should be required viewing for every healthcare practitioner. I wish I had seen it when I was a medical student!

If these kinds of videos have benefited you or your loved ones, please consider becoming a monthly supporter.

This is the final installment of a three-part series. If you missed the first two, check out Reversing Diabetes with Surgery and Reversing Diabetes with Food.

For more on the remarkable work of Dr. Kempner, see:

For more related videos, give one of these a try!

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:

Why Drugs and Diet Can Sometimes Fail in Diabetes

“People with type 2 diabetes are at elevated risk for a number of serious health problems, including cardiovascular disease, premature death, blindness, kidney failure, amputations, fractures, frailty, depression, and cognitive decline.” In other words, the higher people’s chronic blood sugars are, the more heart attacks and strokes they have, the shorter their lifespans, and the higher their risk of complications such as blindness and kidney failure, which I discuss this in my video When Drugs and Diets Don’t Lower Diabetes Deaths.

A study was designed in which 10,000 diabetics were randomized into an intensive blood sugar-lowering intervention, where they put people on one, two, three, four, or five different classes of drugs, with or without insulin, to drive blood sugars into the normal range. Of course, this is not treating the underlying cause—that is, the actual disease—but by lowering one of the effects of the disease by any means necessary, these high blood sugars, the hope was to prevent some of the devastating complications. How did they do?

The intensive blood sugar lowering with drugs increased mortality. After reviewing mortality trends, they concluded that the harm associated with the increased risk of death outweighed any potential benefits, and they stopped the study prematurely for safety reasons. They were successful in bringing down people’s blood sugar, but in trying to push people’s hemoglobin A1c under six, they ended up pushing people six feet under. They speculated that this may have been due to the adverse effects of the very drugs used to treat the disease.

Even just injected insulin itself may promote cancer, obesity, and atherosclerosis, worsen diabetic eye disease, and accelerate aging. Insulin therapy may promote inflammation in the lining of our arteries, which may help explain the results of that drug trial and other trials like it that showed the same thing: no reduction in so-called “macrovascular” complications—heart attacks and strokes—with intensive blood sugar lowering. However, intensive therapy was associated with a 21 percent reduction in the development of microvascular complications like kidney dysfunction.

Any such benefits should be weighed against the increased risk of dying, increased weight gain, and increased risk of severe hypoglycemia in intensively treated patients. So, trying to normalize people’s blood sugar with medications alone may not be the best  idea. “It also should be noted that these trials relied virtually exclusively on [drugs] and did not include any serious effort at [diet and other] lifestyle change…”.

A study published in the New England Journal of Medicine found that an intensive lifestyle intervention focusing on weight loss did not reduce the rate of cardiovascular events such as heart attacks in overweight or obese adults with type 2 diabetes. It did not increase their risk of death, but it didn’t seem to decrease it either. In fact, the trial was stopped after about 10 years on the basis of futility—participants lost weight, but they weren’t dying any less. That’s what we see across the board with these types of lifestyle interventions. It’s good that the dietary intervention wasn’t killing anyone, but why wasn’t it actually helping people live longer?

Because they didn’t actually put them on a healthier diet.

They just put them on a smaller diet––a calorie-restricted diet––meaning essentially the same lousy diet, but just in smaller portions. If we eat less and exercise more, we can lose weight, get more physically fit, get slimmer, and have better blood sugar control, but if our diets continue to be so un-heart-healthy that our bad LDL cholesterol doesn’t improve, we’re not going to be unclogging our arteries. Whereas individuals following healthier diets may experience not only improved reductions in blood sugar and body weight, but cardiovascular risk as well. Yes, by eating a smaller quantity of food, without changing quality, we can lose weight, but the point of a lifestyle intervention is not to just fit people into skinnier caskets.


What kind of diet does help diabetics? See How Not to Die from Diabetes and Plant-Based Diets & Diabetes. You’ve probably heard that Diabetics Should Take Their Pulses. Why is that the case? See Why Is Meat a Risk Factor for Diabetes? and How May Plants Protect Against Diabetes?.

Healthier diets can even reverse some of the complications of diabetes once thought irreversible. See Can Diabetic Retinopathy Be Reversed? and the part of my annual review From Table to Able: Combating Disabling Diseases with Food that discusses the remarkable reversal of painful diabetic neuropathy.

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: