Cardiovascular protection from Tea – Tea 3

//Cardiovascular protection from Tea – Tea 3

Tea is the second most popular beverage in the world, second only to water. It is classified by level of fermentation into black tea, drunk mostly in Europe, North America and North Africa, oolong tea and green tea, drunk mostly in Asia. The beneficial effects are largely felt to be due to the polyphenols, which are the antioxidants found in tea. Green tea is particularly high in catechin, also known as tea flavonoids, which may protect against cardiovascular disease (CVD), by acting as antioxidants. Flavonoids in vitro, can prevent the oxidation of the LDL cholesterol particle that is instrumental in the progression of heart disease. It is also useful in appetite suppression and an aid for fasting. At our Intensive Dietary Management fasting program, we recommend tea often for these benefits.

The benefits of tea are largely found in epidemiological studies, which are problematic, to say the least. However, it is impossible to randomize people in a 10-20 years trial because it’s crazy expensive. The benefits of tea, while highly suggestive, is not definitive. Tea is one of the richest sources of phytonutrients available, containing minerals, antioxidants and amino acids. The nations of East Asia, like Japan and China are among the largest drinkers of tea in the world. Perhaps not coincidentally, they also have some of the highest life expectancies in the world.

As noted in a previous post, the large Dutch cohort from the EPIC trial found lower risk of heart disease with 3-6 cups per day. The 2002 Rotterdam study was a prospective study of aging in 4807 patients followed over an average of 5.6 years.  found lower risk of heart attacks in tea drinkers versus non tea drinkers. What it found was astounding. Those who drank about 2 cups had 42% lower risk of a fatal heart attack, and those who drank >375 mL/day had a 70% lower risk!

Some studies find less effect with black tea compared to green tea. A dose-response meta analysis suggests that each additional cup of green tea drunk per day reduces the risk of heart disease by 1-18%. This can be explained by the higher catechins in green tea which may improve endothelial function and decrease platelet activation.

Green tea has also shown a strong protective effect against stroke, as seen in the 2006 Ohsaki study in Japan. 40,530 Japanese adults were followed for an average of 11 years of follow up. Overall risk of death decreased by 15%, death from heart disease down by 26% and death from stroke down by 37%. By contrast, the Dutch EPIC study did not find a protective effect. Why the discrepancies?

First there may be a difference between the types of tea – green versus black. Studies primarily from European populations tend to drink black tea. Drinking 3 -6 cups per day sounds pretty daunting but there are some important things to keep in mind. Green tea generally has much higher concentrations of the catechin that are believed to be protective. So it may not be necessary to drink that much green tea to derive some of the benefits. Secondly, even when drinking black tea or oolong tea, there’s a difference between the way it’s drunk in Asia and in the West.

In Toronto, Canada, where I live, people often buy tea from the coffee shop. They pay $1.50 or so for a tea bag and some hot water and drink it in much the same manner as coffee. It’s something you purchase to drink. If you drink 6 cups a day, as done in some of these studies, you would be shelling out $9 per day, just to drink tea. That’s not the way it’s done in Asia. My parents are from China, and I grew up drinking tea like water. A tea pot full of tea leaves was steeped over and over again and whenever you are thirsty, you would pour yourself some tea. I drank mostly oolong growing up. Now I’ve switched to green tea. At restaurants, it’s the same thing. When people go out for lunch ‘yum cha’, it means literally ‘to drink tea’. A pot of tea is kept on the table and the waiter would keep refilling it with hot water as needed. Everybody at the table keeps drinking tea throughout the entire meal. At many homes, people do the same. Instead of getting a glass of water with dinner, they might refill the tea pot and drink some hot tea.

What’s the result? Tea is the default drink throughout the day. In the West, water is generally the default drink, and if we want something else, we’ll drink coffee or tea. In Asia, the default drink is tea, and therefore you can easily drink 6 or 8 cups a day without even thinking about it, where North Americans may drink 6-8 glasses of water instead. That’s the best case scenario. Many children would drink sugary sodas or fruit juices instead.

There’s another important difference in tea drinking in the East and West. Traditionally, in the East, you generally drink tea ‘straight’ and do not add sugar or cream/ milk to your tea. Modern Asia has changed, with many tea houses now blending teas with a variety of flavours, cream/ milk and sugar. For sure, adding sugar and other flavours is bad, but what about milk?

In the United Kingdom, it is estimated that 99% of tea drinkers add milk to their tea. Does this make a difference? Flavonoids are bound to protein and adding milk may abolish much of the antioxidant effect. The flavonol quercetin, found in green and black tea, onions and red wine, is reported to reduce the oxidation of LDL cholesterol and block platelet aggregation that may reduce heart disease. The Caerphilly study followed residents of the town of Caerphilly in South Wales and compared rates of heart disease to intake of flavonols. Tea provide 82% of the flavonols and onions 10%. In this study, there was no reduction in heart disease with increased tea drinking, in contrast to several other studies. There was one potentially important difference between tea drinking in the UK and other parts of the world including the Netherlands. In this sample, 99% of tea drinkers added milk whereas this practice is (was) rare in places such as Asia. There is some experimental data that milk proteins may bind the flavonols and prevent full absorption by the body. One experiment showed that adding milk to tea completely blocked the antioxidant effect of black tea.

Because tea is so widely consumed, the potential for changing health is immense. Even if there only exists a small benefit for tea, when multiplied by billions of people drinking it multiple times per day, it can add up to substantial benefits for public health.

A meta analysis of all studies done in 2001 which included 10 cohort studies and 7 case-control studies (a weaker study design). This suggested that overall, the consumption of 3 cups of tea daily was associated with an 11% reduced risk of CVD, although the studies were small. Interestingly, two small studies from the United Kingdom showed an increase in heart disease risk with more tea drinking. This may be the effect of additives (sugar and milk) to the tea, rather than tea itself, but the studies cannot tell for sure. Also, the difference between green and black tea may be of importance.

Once again, the bottom line is relatively simple. There are many potential benefits. The potential risks are virtually non existent. The cost is low. Drinking tea comes with a very high benefit/risk ratio, so why not do it?

2018-04-22T22:31:59+00:00 18 Comments

About the Author:

Dr. Fung is a Toronto based kidney specialist, having graduated from the University of Toronto and finishing his medical specialty at the University of California, Los Angeles in 2001. He is the author of the bestsellers ‘The Obesity Code’ and ‘The Complete Guide to Fasting’. He has pioneered the use of therapeutic fasting for weight loss and type 2 diabetes reversal in his IDM clinic.

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18 Comments on "Cardiovascular protection from Tea – Tea 3"

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Jim
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Green tea has been a habit of mine for forty years. Because it tastes good, not for health. Recently, I find health benefits are mentioned more often. Win win. Thanks for what you do Dr Fung.

Richard
Guest
I’m having my morning green tea, right now. My thanks to Dr. Fung for this article and research. I have read before, from other sources, regarding the benefits of the green tea catechin. It seems pretty clear to me that green tea, in terms of the benefits is the best choice, considering everything. On the other hand, what this post also says is that the Asians getting the most benefit from this are NOT drinking milk with their tea, and NOT having snacks and sugary treats with their tea. Is there some non-snacking, non-milk drinking (etc) control group that we… Read more »
Anna
Guest

I loved your description of how tea is drunk in China. It has inspired med to take out my teapot and always have a green tea brew going on. The habit of filling up the pot, filling up my cup and sipping tea, might just help me replace a worse habit I have, of “grazing” nuts in the afternoon. Today it worked perfectly. Green tea is very satisfying! No craving for nuts!

Mike
Guest

“Flavonoids are bound to protein” – so does that mean that drinking the green tea with or after food, when there is protein in the stomach, is also likely to be less effective? It needs to be on an empty stomach?

Kelly P.
Guest

I would love to know the answer to this question, too. Seems logical that eating with your tea would have the same effect as putting milk in it.

Roger
Guest

White tea is my favorite, then oolong and green with an occasional rooibos chai chaser. Too bad Teavana went under, any ideas on a comparable online source?

Sam
Guest

Try teatrekker.com. Fantastic quality, a bit pricey but well worth it.

Henry
Guest

I would recommend Pique Tea. I tried it and have been loving it so far.. really helps with the cravings. Dr. Fung has a special offer here: https://offers.piquetea.com/dr-jason-fung/?afmc=JASONFUNG&utm_source=affiliate&utm_medium=email&utm_term=Jason%20Fung&utm_content=Jason%20Fung

Sam
Guest

Green tea is also a good source of PQQ in the diet, if you drink a lot of tea daily. Good for mitochondrial health.

Roxymusic
Guest

Hi Dr. Fung, just wanted to mention that a direct link to your blog doesn’t work; you have to go in through the main page.

2Blackdogs
Guest

As far as the UK goes, Brits tend to eat a lot of sweet baked goods with their tea as well as putting milk in it. I drink my three mugs a day of black tea plain. Perhaps it’s time to switch to green. In the past , I have found it to be an acquired taste, one I have not acquired.

Dave
Guest

Dr. Fung, do you have any research or information about Moringa Tea?

TeeDee
Guest

Great article, thanks. I can easily believe that the addition of milk and/or sugar to tea would negatively impact the health benefits of tea. It just makes sense. I no longer consume milk, cream or sugar, so it wouldn’t be a problem to drink it ‘straight up’ as you mentioned. Black tea can upset my stomach for some reason, but I’m going to give green tea a serious try. I tend to drink a lot of herbal tea when the weather is cool/cold, so that’s where I get the majority of my water intake for most of the year.

Kelly P.
Guest

Thanks for this article! Looking forward to the Pique Fasting teas. I just ordered some of their “regular teas” to try them out. I have never really enjoyed green tea, but found that I love Good Earth “Matcha Maker” green tea, and can drink it with no sweetener. It’s delicious!

Johanna
Guest

Thank you very much indeed for all the information you post.
(I’m on my fourth day of my first fast. It’s going well.)

A quick question. Freshly brewed green tea has always given me monster headaches. I’ve tried many sorts and methods/times of brewing. I do drink and enjoy Jun (when not fasting) which is fermented green tea and honey – similar to Kombucha. I also enjoy and drink a lot of black tea. Does anyone know if these have the same benefits as brewed green tea?

Thank you for your answers.

Elizabeth
Guest

Being a Brit/Canuck, most people think I drink tea. Actually, my usual drink is coffee or oolong tea. The latter I only discovered recently but find it refreshing and not bitter like black tea. My Ma-in-Law thought I was nuts because I would only accept the very first pour from the pot!

Benthamite
Guest
Even excellent researchers go down the wrong alleys. This praising of tea by Dr. Fung troubles me for three reasons: contravening variables, cognitive dissonance, and low dose. The tea drinkers differ in lifestyle from the general population, too many miracle foods entails both confusion and missing the main causes, and a low dose of antioxidant isn’t protective. I take 2 grams of vitamin C and 300 mgs of CoQ10, tea flavonoids are far less, and there is no invivo studies to prove their bioactivity. The wikipedia article on flavonoids states “most of what is absorbed being quickly metabolized and excreted.[21][37][38],”… Read more »
Richard
Guest
I find your post puzzling. A high fructose diet? Who would do that? Why? Reading your post on a broad scale, the inference seems to be that better results could be obtained by simply making sure one were drinking plenty of pure water. But Dr. Fung has already recommended that. In another comment by another reader, the suggestion is made that drinking green tea resulted in a reduced consumption of nuts (not my snack of choice, but I do like nuts), and so the tea suggestion was beneficial, in terms of fasting, which is, as I see it, the purpose… Read more »