Tea, Weight Loss, and Control Studies

The Linus Pauling institute at Oregon State University has an outstanding page summarizing recent scientific research on the health effects of tea. This page makes an interesting comment about tea and weight loss:

"It is currently unclear whether tea or tea extracts promote weight loss. Large-scale clinical trials that control for energy intake and expenditure are needed to answer this question."

Are control studies really what we want here?

Western science is based around the idea of controlled studies that isolate one variable and examine the effect of changing that variable when others stay constant. But do controlled studies actually capture what happens in a practical setting? Not at all.

Drinking tea has many mechanisms by which it can influence weight loss through influencing energy intake:

• Tea is a calorie free drink. Tea can be consumed as a substitute for calorie-rich drinks such as soft drinks, milk, fruit juice, or energy drinks. In this case, drinking tea could directly reduce someone's calorie intake.


• Tea can be quite bitter, and is generally not very sweet. Drinking unsweetened tea on a regular basis could change people's tastes, making them more accustomed to foods that are less sweet. This could reduce their calorie intake through reducing refined sugars in their diet.


• Tea contains caffeine, which is known to reduce appetite. Tea also contains a myriad of other chemicals, many of which are poorly understood. It is reasonable that tea could have other effects on appetite and food preferences beyond those caused by caffeine as well. Either way, drinking tea is likely to lead people to reduce their calorie intake overall.

Controlling for energy intake is missing the point. People want to know whether drinking tea will help them lose weight. The vast majority of these people, even those who count calories some of the time, do not effectively control their energy intake the way a scientific study would. People interested in weight loss in the practical setting of their own lives will be more interested in how drinking tea will influence their caloric intake through appetite, food preferences, and any other means. Control studies are missing the point!

Oh, and one last observation--tea extracts do not have the first and second benefit above. Actually drinking tea is necessary to get the full weight-loss potential, since part of the way tea can help you lose weight is through the act of drinking and tasting it, not just through chemicals that you can pop in a pill.

Other Camellias for Tea

The Tea Plant, Camellia sinensis, pictured on the right, is a member of a large genus, Camellia. As with the taxonomy of most species, there are different ideas about how many distinct species there are; the American Camellia Society's page on Camellia Species says that different authorities estimate the number as between 80 and 280...which is a lot.

Few camellias are used for tea other than Camellia sinensis. I found a few sources, including Monrovia's page on Yuletide camellia, that said that the Yuletide camellia, also known as the Christmas Camellia, Camellia sasanqua, is sometimes used to make tea in Japan. Wikipedia also includes this claim, but without giving a source or reference. The same plant is also used to make "tea seed oil". Oil (used for cooking) is also made from Camellia oleifera, and a number of other camellias.

So what about making tea from other camellias?

I am an inherently curious person...I always think of new possibilities, and I admit I am insanely curious about this one. What would it taste like? Granted, it probably wouldn't taste great right off the bad, since the tea plant has been cultivated for hundreds if not thousands of years to yield the beverage we drink today. But...it just seems too obvious a possibility to pass up.

Has anyone done this? Does anyone know anything about this sort of thing?

I'm tempted to try making some tea myself, from Camellias growing here in Delaware...

I guess another philosophical question...would it be tea, or would it be "herbal tea"?

Update: Nigel Melican (teacraftecm on twitter) has informed me that C. irrawadiensis & taliensis, also caffeine-free, make weak "non-commercial liquors". Now I at least want to look into these other species!

Tulsi / Holy Basil: Research Motivated by Taste

I just researched and created an article on Tulsi / Holy Basil.

The interesting thing about this article is that this was an herbal tea that I had not "naturally" stumbled upon in the course of adding teas to RateTea, something I've been doing for months now. I have added all of the teas from a number of tea companies, including Adagio, Rishi, Teavana, and a number of smaller companies. While I haven't checked to see whether or not these or other companies blend tulsi into their teas (I know Yogi does), I do know that these companies don't carry a pure tulsi blend.

How did I find out about this plant? I have been sampling many of Upton Tea Import's teas, and I ordered a sample of their green- and purple-leaf tulsi teas. I tried the purple-leaf variety first, and I fell in love with the first sip...this stuff is delicious. (My review of Upton's Purple-leaf Tulsi on RateTea)

Interestingly, it was the taste and overall experience of drinking the tea that motivated me to start researching the plant. I was surprised to find a huge amount of scientific literature on this plant, a plant which I had barely heard of and knew nothing about before seeing it in Upton's catalogue. Although a lot of the research is young and preliminary to a degree, there's a great diversity of research out there, and the evidence mostly points in the direction of this plant having numerous health benefits...I had to pick and choose a few studies that highlighted the various beneficial properties of this plant. This whole experience seems to reinforce my strange idea that taste can possibly be a guide to health...

View the results of my research: Tulsi / Holy Basil

Tea & Health: Beyond Chemistry?

A post on Vicki's Nutritonal and Wellness Blog draws attention to a study that found that positive emotions and positive attitude actually has more of an impact on health than nutrition. Negative attitude, stress, anger, and that whole complex of feelings and ways of being are associated with a myriad of negative impacts on health.

The health benefits of tea are frequently touted, and some of them (such as antioxidant activity) have become fairly well-established scientifically. But nearly all of the studies I've found about these benefits focus on the biochemical aspects of tea.

Could the health benefits of tea be partly due to how making and drinking tea slows you down?

It seems almost too common-sense to be true...a cup of hot tea...you can't chug it on the run...even if you're in a hurry you need to slow down to sip it, you need to wait to let it cool. And if you make it yourself, even from a hot water tap in an office, you need to take time out of your day to brew it. It slows you down, relaxes you, helps you let go some of that stress and get into a better place...

Maybe some of the health benefits of tea stem not from the chemistry of the drink itself, but from the process of making and drinking it, and the effect that process has on your mind and body. This would certainly not be any news to those versed in eastern philosophy or Chinese medicine...but to an overly-scientific western mind, it's an innovative idea...and it would certainly be worth it for the scientists to give it some consideration.

Just a thought!

Locally Grown Tea

There are a lot of issues relating to both sustainability and tea. My page on RateTea summarizes a few of them. A lot of them, including fair trade, organic certification, and composting, are topics that most people are familiar with and that a fair amount has already been written about. I'm starting to think about another issue, however.

People don't talk much about locally-grown tea in the U.S. and Western Europe. It's generally assumed that tea grows in warm, tropical climates and needs to be imported in these countries. But this is not true. The tea plant, Camellia sinensis, is a relatively hardy plant, and while it generally likes a subtropical climate, it can be grown farther north than many people realize. Many of the famous tea-growing regions, such as the Darjeeling district of India, or nearby Nepal, are located at a high altitude where the temperature can actually get fairly cold and sometimes drop below freezing in the winter.

It would make sense that the continental U.S. and western Europe would have a number of areas suitable for growing tea, especially in the more moderate areas. Some interesting commercial tea operations prove this:

• Pembrokeshire Tea Company's Tea Gardens - Located in Pemrokeshire, on the coast of Wales. - This claim has been since taken down, and I have received reports or allegations that this claim was fraudulent, and that no tea was ever commercially produced here.
• Sakuma Brothers Tea - Grown in the Skagit Valley of Washington State
• The Charleston Tea Plantation - Owned by Bigelow Tea and located near Charleston, SC.

Herbal teas:

Herbal teas, encompassing virtually any plant used in tea other than the tea plant, grow virtually everywhere that plants grow, from the tropics to the arctic. North America and Western Europe, in particular, are the origins of a countless variety of delicious herbal teas. Many of these can be easily grown in your own garden or backyard. Many plants used for tea, such as mint, are aggressive in certain climate zones, and can be grown in massive quantities with minimal effort. In addition to growing tea yourself, many herb teas are available locally--not just through small retailers but also from friends and neighbors who might have more gardening space (or expertise) than you do.

Why locally-grown tea (or locally-grown anything) is good:

Locally-grown anything, including tea, is important for promoting sustainability in that it:

• Reduces transportation costs
• Improves self-sufficiency - helps make your region (and you) less dependent on the outside world
• Promotes diversity, especially in tea - because the flavor of any plant source of food or drink depends on the conditions in which it is grown, and the climate and soil conditions vary from one region to the next, each area will produce tea (and other produce) with a unique flavor.
• Creates economic stability - droughts or disasters often happen only in one region of the world; as the total supply of a commodity becomes produced in more regions, the supply and price become more stable in the face of events that could catastrophically effect one source of the commodity.
  

Buying locally grown tea is something that only a few people in the U.S. and western Europe can do right now...but drinking locally grown (buying or growing your own) herb tea is something that almost anyone can do. But it's certainly something worth thinking about!

Article on Caffeine Content of Tea

Everyone is always asking me which teas contain the most or least caffeine...so I did some google scholar research and found a couple good articles, which I read, processed, and summarized in an article on caffeine content of various teas.

The basic gist of it...you can't make generalizations about types of tea like green tea, black tea, or white tea containing more caffeine or less caffeine. Rather, the caffeine content varies more from tea to tea. Tippy teas contain more caffeine, and roasted teas contain less, roughly in proportion to the amount of tips, and the amount of roasting.

So...don't believe those claims out there about how white or green tea is "lower in caffeine" than black tea. It's not! Teas of all types are quite diverse and span a broad range of caffeine contents.

Antioxidants: Is bitter tea better?

I've been reading a book lately, Tea: Bioactivity and Therapeutic Potential, which is a collection of rather dense, scientific article about different facets of tea's biological activity.

I quote from the first article, by Miao-Lan Chen:

The catechins that are water-soluble, colorless compound[s] contribute to astringency and bitterness in green tea.

Catechins are the well-known antioxidants present in all tea. Not all of them are water-soluble, colorless compounds. And the authors stops after this remark and does not draw any inferences. But if catechins are bitter, could it possibly be that bitter teas are perhaps better for you? Just a thought...I've noticed that over time, my taste for bitter food and drink has developed considerably. The thought behind this had crossed my mind before, which is what was behind my rather far-out and speculative article on tea tasting for health.

Either way, I like bitter tea...so I'm going to keep drinking it just for taste!