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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.

All the Tea in China: Stop 1 on the World Tea Tasting Tour


Guangzhou teapotLegend says that tea originated in China in 2737 B.C., over 100 years before the first Egyptian pyramid was built. In this first stop on our tasting tour, we explored China’s best-known tea growing areas in Yunnan, Anhui, Zhejiang, and Fujian provinces. We also took a look at traditional Chinese teaware, including gaiwans and guangzhou teapots.

The teas we tasted were:

  • Organic Longjing Dragonwell (green)
  • Organic Pinhead Gunpowder (green)
  • Jasmine Dragon Tears (green)
  • Silver Needle (white)
  • Organic Shui Xian Wuyi Oolong
  • Organic Keemun Mao Feng (black)
  • Organic Golden Yunnan (black)

We started out by taking a look at the legend of the history of tea, going back to Emperor Shennong in 2737 B.C., and then talking about the major tea growing provinces of China. Four provinces were represented in our sampling: Yunnan, Anhui, Zhejiang, and Fujian. Obviously, this is just a beginning, but in a single short class, we can’t hit them all.

China - Slide04

After the background was covered, including varietals of the tea plant, we launched into the individual teas, organized by style.

White Tea

First was white tea, the most lightly processed. I chose a Silver Needle blend from Rishi instead of a single-origin tea for this one mostly because our focus was comparing Chinese white tea with green and oolong teas. At some point down the road, we’ll do a comparative white tea tasting where the focus will be on terroir and origin.

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One of the bullet points on the slide is an important one: busting the caffeine myth of white tea. The fact that this tea is made from early-picked buds means that there is a high concentration of caffeine. The preparation style does nothing to change that. The longer steep times we typically use on white tea just accentuates this.

We steeped the tea for five minutes in 165 degree water.

Green Tea

I chose three different green teas for the tasting. Each brought something completely different to the party.

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First – a straight green tea very typical of Chinese fare, with a history dating back well over a millennium. The name of the tea comes from the finely-rolled leaves resembling gunpowder.

We steeped the gunpowder tea for three minutes in 175 degree water.

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I simply couldn’t resist including the original story (fable?) of Longjing tea here, which I’ll be covering in much more detail in the future. Of all of the green teas I’ve tried, this is the one I keep coming back to as my favorite.

We steeped the dragonwell tea for three minutes — although I only do two minutes when I’m brewing it for myself — in 175 degree water.

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And finally, we come to the only flavored tea of the evening. We followed tradition with this tea, placing seven tears in each cup and sipping the tea as the leaves unfurl. Unlike all of the other teas we tasted, this one didn’t have a fixed steeping time. Everyone began sipping after a minute or two and kept sipping as the character changed over the next few minutes. We used 175 degree water.

Oolong Tea

We could have easily set up an entire evening just tasting Chinese oolongs (we are, in fact, doing this with Taiwanese oolongs on March 29), but for tonight we chose only one: an oolong from the Wuyi mountains.

China - Slide21

It was a very difficult choice deciding which oolong to include. My first temptation was Tieguanyin (Iron Goddess of Mercy), but since I had two rolled teas already I decided to go with an open-leaf oolong.

We brewed this for three minutes in 195 degree water.

Black Tea

And finally, we moved on to black tea. Choosing only two black teas to represent China wasn’t easy (although it was a lot easier than choosing a single oolong), so I simply went with my two “leaf and a bud” favorites: one fully oxidized rich black with overtones of red wine (Keemun Mao Feng) and one lightly oxidized golden tea from Yunnan.

China - Slide25

China - Slide26

This was another case where I steeped the teas both at three minutes in boiling water for a better comparison, but when I drink them myself I prefer about 2:30 for the Keemun and 4:00 for the Yunnan.

We closed out the evening with a discussion of steeping times, water temperatures, multiple infusions, and other factors involved in preparing a great cup of tea. As always, I ended with the admonition to ignore the Tea Nazis and drink your tea however you like it.

There is no wrong way to enjoy a cup 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).

Free tea! It doesn’t get better than that


Bag of Chinese tea

The mysterious bag of Chinese tea.

A friend of mine stopped by the tea bar the other day. Unlike most tea bar visits from friends, Wanda brought tea in with her. It was a bag of tea from China that a friend had given her. She didn’t know what it was, and she’d had it for five years, so she asked if I’d like to have it.

I cut the bag open and poured out a bit of the tea. It was full rolled leaves; not rolled tightly into balls like Dragon Tears or gunpowder tea, but pretty dense nonetheless. The leaves were hard; dropping them into bowl made a pinging sound. The color was a bit darker than a typical green tea, and the smell reminded me of the Huang Jin Gui oolong we carry at the tea bar.

I brewed a cup — using a bit more tea than I usually would because of the age — and decided it was definitely a oolong, but I couldn’t quite identify it. Good packaging, by the way. Five years old, and it still tasted good.

Here’s where Facebook comes in handy. I took a picture of the large print on the top of the bag (the photo that’s now on this page), posted it on Facebook, and asked if anyone could identify it. Within about 20 minutes, I had my answer: Iron Goddess of Mercy, a lightly oxidized oolong with a unique aroma. After enjoying it for a few days, I started hunting for a good one to carry at the tea bar, and I’m excited to have a fresh batch coming in next week. Given how good the five-year-old stuff at home is, I have a feeling I’m really going to love the fresh tea.

Iron Goddess of Mercy (called “Tae Guan Yin” in Chinese) originated in Anxi, in the Fujian province of China. Today, it is produced in quite a few other areas of China and Taiway. The one we sell at our tea bar is a medium-roasted variety from Nantou, Taiwan. I’ve used the leaves for three infusions without loss of flavor, and I’ve been told they’re good for as many as seven.

The processing of Tae Guan Yin is complex. Traditionally, it follows these steps:

  1. Picking – usually done early in the day when it is sunny
  2. Sun drying (“withering”) – Done  before sunset the same day as the picking
  3. Cooling (“cool green”) – Done overnight, along with the tossing
  4. Tossing (“shake green”)
  5. Withering/partial oxidation – Done the day after picking
  6. Fixing
  7. Rolling/kneading
  8. Drying
  9. Roasting

There are several conflicting legends regarding the origin of Iron Goddess of Mercy, all recounted on the Chinese Tea Culture site. Personally, I much prefer the Wei Yin legend. I don’t know that it has any more veracity, but it’s a better story.

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