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Tips for reading news about tea studies


Header - Tips for reading news about tea studies

As Dr. Oz is being thoroughly (and rightfully) shredded by the Senate Commerce, Science, and Transportation Committee for pimping weight-loss scams, we shouldn’t lose sight of the fact that (a) there are a lot of valid health benefits to tea, and (b) virtually every news story about tea and health manages to misrepresent or misinterpret the scientific study they’re describing.

As you read articles about tea and health, it’s important to keep in mind that the person writing the article is usually not the person (or people) who actually performed the study it references, and that the reporter/blogger may have read only the summary, not the whole study. Also, in larger news operations, the person writing the headline isn’t the same person who wrote the article, and if they’re operating on a deadline, the headline may not accurately sum up the story.

Tip 1: Beware of extreme claims

There’s an article on Authority Nutrition entitled,”How Green Tea Can Help You Lose Weight Naturally.” It’s worth reading. There are good explanations of the benefits of tea, and it cites dozens of actual scientific studies. But any article that begins with a statement like “green tea is the healthiest beverage on the planet” should set off alarm bells. No, there’s never been a study that tested every single beverage on the planet (there’s never been a study of every style of tea on the planet, for goodness’ sake). No, we don’t have a generally-accepted definition of “healthiest beverage.” An opening sentence like that one tells you you’re about to read something sensationalistic, and you should view everything they say with skepticism.

Any article that begins with a statement like “green tea is the healthiest beverage on the planet” should set off alarm bells.

Tip 2: They only studied what they studied

There’s an article on Byron J. Richards Wellness Resources entitled, “The Effects of Green Tea on Weight Management.” The author is a Board Certified Clinical Nutritionist, the studies cited all appear to be properly-conducted randomized controlled trials, and the conclusions all appear to be valid. So what’s the problem? Reading this may make you want to rush to your tea cabinet and throw away all of those white teas, oolong teas, yellow teas, and pu-erh teas. You need to replace those all with green tea, right. Wrong!

The studies looked at green tea. Specifically, they measured catechins and caffeine in green tea. They never compared green tea with white tea — or any other kind of tea. White tea may be even better for weight loss. So might oolong, pu-erh, or yellow. If green tea is measured against anything else in a study, it’s almost always black tea. What’s the difference between green and black tea? Black tea is oxidized, and that process converts a lot of the antioxidants into other compounds (catchins are a type of antioxidant). But white and yellow tea isn’t oxidized, and oolong is only partially oxidized. Shu pu-erh is oxidized and fermented, and sheng pu-erh is fermented without being oxidized first. Don’t draw conclusions about your oolong from a study that never even looked at oolong!

Tip 3: There’s more to tea than antioxidants

I think it’s pretty universally agreed that antioxidants are a good thing, but they aren’t the only source of health benefits in tea. When I got in a tiff with Fox News’ Chris Kilham about misrepresenting studies, it related to a study that showed coffee had some great health benefits. Reading the study showed that it looked at one thing: caffeine. All of the health benefits it listed for coffee would apply just as much to tea, guayusa, yerba maté, or Mountain Dew. If you like black tea, don’t let yourself get talked out of drinking it just because it doesn’t have the same antioxidant content as green tea.

Tip 4: All green tea is not created equal

It’s wonderful to see an article like the one titled, “Green Tea,” on the University of Maryland Medical Center page. It has tons of information, cites numerous studies, and explains potential drug interactions and side effects. But, like all of the other articles, it just references “green tea.” Did they test Japanese steamed green tea like sencha? Pan-fired Chinese green tea like longjing? Or was it roasted (hōjicha), powdered (matcha), shade-grown (gyokuro), scented (jasmine), or rolled (gunpowder)? The Kevin Gascoyne study I referenced in my 3-part series on caffeine found tea caffeine content ranging from 12mg to 126mg per cup. Yes, the most caffeinated tea had ten times as much caffeine as the least. He found a similar range of antioxidant contents. If you want to replicate the results of the study, you have to know what kind of tea they used.

Tip 5: Pay attention to who funded the study

If they had done a study that found that green tea gives people smelly feet, how much publicity do you think that would have gotten?

You can’t automatically discount a study because the funding group had something to gain from it. Tea companies are the ones most likely to fund tea studies, after all. But take a look at “Green Tea Promotes Weight Loss, New Research Finds,” an article on Medical News Today (well, actually, it’s a press release, but they don’t make that obvious until the end). It’s very clear in reading the article that Lipton did the research, and that Lipton is very excited about having done the research. It’s a big company, and their PR department did a good job of really spreading the news about that study.

If they had done a study that found that green tea gives people smelly feet, how much publicity do you think that would have gotten? I always tend to pay a little more attention to research coming from neutral parties, or research that’s been duplicated by neutral parties.

Tip 6: Check to see if the methodology was realistic

WebMD has an article entitled, “Green Tea Fights Fat,” which does appear to actually compare weight loss effects of green tea with oolong tea. But read this sentence from the article carefully: “For three months, the first group drank a bottle of oolong tea fortified with green tea extract containing 690 milligrams of catechins, and the other group drank a bottle of oolong tea with 22 milligrams of catechins.”

First, they aren’t comparing green tea with oolong. Both groups drank oolong tea. In one group, they added green tea extract, and in the other, they didn’t. So this study actually compares drinking oolong with drinking oolong plus green.

Second, the average cup of green tea has 50-100mg of catechins. That means the “extract” they fortified the bottle of oolong with made it equivalent to 7-14 cups of green tea. That’s a lot of tea!

 

If you have specific reasons for controlling your intake of caffeine, L-theanine, catechins, and other components, then there’s plenty of research to plunge into. Focus on people who actually study tea rather than folks like Dr. Oz or Oprah. Look at the paper and see what they actually studied. If it doesn’t apply to you, move on to the next one. If it does, take it at face value without trying to overgeneralize.

But if you’re just looking for a healthy drink that tastes good, stop worrying and buy more of what you like the most. You’re likely to drink a lot more of a beverage you love than one you don’t. If you like to experiment, all the better! If you drink a wide variety of tea, you’ll get a wide variety of nutritional benefits, and you can enjoy yourself as you do it.

Japan – Bancha to Matcha: Stop 4 on the World Tea Tasting Tour


In 1191, a Buddhist monk named Eisai brought tea to Japan, and the tea world has never been the same. In Japan, when you say “tea,” you mean “green tea,” and that’s what we focused on. Japan is known for its grassy steamed teas, so we started this event there. We went on to some of Japan’s lesser-known specialty teas, and wrapped up with matcha, the powdered tea used in the Japanese tea ceremony, which we import directly from Japan.

Japan title slide

We’re very excited to be working with resident artist Karin Solberg from the Red Lodge Clay Center, and we are featuring some of her matcha bowls in the store, and she came in to talk about them at this stop in the tour.

The teas we tasted were:

  • Organic Sencha
  • Gyokuro
  • Organic Houjicha (roasted green tea)
  • Organic Genmaicha (toasted rice tea)
  • Organic Matcha
Japan is the world’s 8th largest producer of tea, with about 119,000 acres cultivated and an annual production of 101,500 tons. These numbers are from before the Fukushima Daiichi nuclear disaster, which has shut down some of Japan’s tea production. The overwhelming majority of Japanese tea is consumed domestically, with only 2,105 tons exported, or about 2% of production. The country that purchases the most Japanese tea is the United States.
We discussed the Fukushima Daiichi disaster at some length, but instead of including that information here, I’m going to write a full blog post about its effect on Japan’s tea industry when I have a chance.
There are four base grades of tea in Japan:
  • Kukicha   (“twig tea”)
  • Bancha   (“coarse sencha”)
  • Sencha   (“decocted tea”)
  • Gyokuro   (“jade dew”)
We did not taste kukicha or bancha, proceeding instead to the two higher grades.
Sencha
Not all organic tea from Japan will carry the USDA Organic seal. Many Japanese tea farmers prefer to work with their own country’s organization and carry the JAS (Japan Agriculture Standard) Organic seal instead.
Gyokuro
Note the short steep times and cool water used for these teas. Recommendations for the top grades of Gyokuro go down as far as 40 degrees C (104 F).
After tasting the two more mainstream Japanese green teas, we went on two a couple of their wonderful specialty blends: Houjicha and Genmaicha.
Houjicha
Genmaicha
We wrapped up the tasting with Japan’s famous powdered green tea: matcha. We tasted a USDA organic matcha from Aoi, prepared in a traditional chawan, or matcha bowl. Then we made matcha lattes using a sweetened matcha powder with frothed milk.
Matcha
We are lucky to have Karin Solberg, a local artist who works in pottery, producing matcha bowls for us. She talked about the traditions of the bowls, how they are made, and why they are designed as they are. All of the bowls in the picture below are Karin’s.
Matcha Equipment
In part two of this article, I’ll talk more about Karin and about the Japanese tea ceremony and the Way of Tea.
If you live in the area and were unable to attend this session, I sure hope to see you at one of our future stops on our World Tea Tasting Tour. Follow the link for the full schedule, and follow us on Facebook or Twitter for regular updates (the event invitations on Facebook have the most information).

What’s the difference between Japanese and Chinese green tea?


sencha leaves

Japanese sencha leaves

As I did last month and the month before, I took a look at some of the search terms that brought people to this blog and found a question that I didn’t really address. This time: “What’s the difference between Japanese and Chinese green tea?” The obvious smart-aleck answer is that one comes from Japan and the other comes from China, but it runs a bit deeper than that.

First off, it’s not the plants themselves. The first varietal discovered of the tea plant is Camellia sinensis var. sinensis: the Chinese tea plant. About 1400 years ago, during the Sui Dynasty, Buddhist monks introduced tea — and the tea plant — to Japan. This means that the same varietal of tea plant is growing in China and Japan.

Terroir, on the other hand, can definitely have an effect. The climate, soil, and other factors can definitely affect the taste of the tea. Also, the Japanese have been crossbreeding and developing their strains of tea plant for over a millennium.

The biggest factor in the taste, though, is a very simple one: the process.

The difference between black tea and green tea is oxidation. Black tea is fully (or near-fully) oxidized, while green tea is not oxidized at all. There is an enzyme in the tea leaf that starts the oxidation process as soon as the leaf has been broken or bruised. Making green tea requires a “kill green” step that destroys the enzyme and stops the tea from oxidizing. That step requires heating the tea leaves quickly to at least 140 degrees.

To make Japanese green teas, such as sencha, bancha, and gyokuro, the leaves are steamed. To make Chinese green teas, such as dragonwell or gunpowder tea, the leaves are pan-fired. Just this simple difference in processing gives Japanese teas a rich grassy flavor and Chinese greens more of a vegetal character.

Granted, I am oversimplifying, but this is the fundamental answer to the question.

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