Thursday February 11, 2010 | 7 comments
After three consecutive months of having fun with tea and sweet indulgences, for this month I’d promised a post on tea as an aid in weight loss. Quite timely…I’m sure I’m not the only one out there looking to wipe off a few holiday-acquired pounds.
The Tea Spot’s expert on tea and metabolism, is, coincidentally enough, our skinniest colleague, Jessica Burtenshaw. This post comes to you thanks to help from Jessica. I appreciate not only her aptitude for all things analytical, but her “voice”. Hope you agree!
If reducing that abdominal paunch is one of your goals for this upcoming bikini season, you might seriously consider adding white tea to your diet. Concern over increases in obesity-related diseases has prompted research into the effects of white tea extract on the human body. The findings, published last year in Nutrition & Metabolism, found that white tea extract effectively inhibits adipogenesis (the production of fat) AND stimulates lipolysis (the destruction of fats). Even Dr. Oz, Oprah’s wellness guru, recommended recently that “you should drink about four cups of green or white tea a day”, which propelled “white tea” to the highest-searched tea term on the Internet overnight! Ahh, the power of Oprah… All this twitter around white tea and weight loss has prompted us to do some more digging to bring you a summary of the facts.
TRUTH or MYTH:
* Simply adding white tea to your diet will help you lose weight – MYTH
* White tea will assist your body in inhibiting the production of fat cells – TRUTH
* White tea provides a boost to exercise-induced weight loss, further stimulating the destruction of fat through exercise – TRUTH
* The caffeine in white tea helps you burn fat by speeding up your metabolism – MYTH
* White tea often contains the least amount of caffeine of all teas. It’s the polyphenol antioxidant EGCG that helps inhibit fat cell production – TRUTH
* White tea is a natural appetite suppressant. And of course, “the weight loss will be even better if the tea is unsweetened and if it’s replacing caloric beverages such as soda,” suggests Shawn Talbott, author and producer of Killer at Large, a documentary exploring the causes of and the solutions to the American obesity epidemic – TRUTH
So go ahead and make white tea your new BFF!
IMAGES: D SHARON PRUITT
Good article. I have one question and one challenge.
First, while I agree that it’s unsafe to tell someone that adding white tea to their diet alone will cause weight loss, it seems to me that this statement stands at odds with the other assertions. Namely, that white tea will inhibit the production of fat cells, stimulate the destruction of fat cells and suppress appetite. IF these last three are true, wouldn’t the addition of white tea cause weight loss if all other factors are held stable? Or are the impacts so small as to have no measurable impact on actual weight?
Second, I would challenge the statement that white tea contains the least amount of caffeine. This is a widely repeated myth that I have yet to see scientific basis for. In fact, the science I have seen suggest that if you brew the average white, green oolong and black tea using the same temperature water for the same time the white tea is likely to have MORE caffeine than any other varietal! (see citation 1 below) The relative caffeine content so often quoted has more to do with brewing temperature and time than content in the leaf (citation 2). If you brew a white tea with cool water for 2 minutes it will have a lot less caffeine than a black tea brewed with boiling water for 5 minutes.
Allow me to come at this from another direction. The claims that white tea has higher antioxidant content IN THE LEAF are true. This is because the newer leaves are the most recent and heaviest recipients of the essential nutrients that the Camellia Sinensis plant uses to grow leaves (citation 3). Caffeine is one of those. Increase levels of antioxidants come with increased levels of caffeine.
In short, those claiming high antioxidant content are talking about leaf content, and those claiming low caffeine content are referring to what gets transferred to the cup!
Citations:
1) 2001 Study by Yang Weili in China
2) Yang DJ, Hwang LS, and Lin JT. 2007. Effects of different steeping methods and storage on caffeine, catechins and gallic acid in bag tea infusions. Journal Of Chromatography. 1156:312-20.
3) Food Research International, Vol 29, 325-330
Charles,
Your point is well taken – in fact, when we refer to caffeine content in a tea, we’re referring to what does get released into the infusion, and not, as you state, what starts out in the fresh leaf.
The caffeine content in a leaf of tea is dependent upon the varietal, the season, soil conditions, and fertilizers used in its cultivation, amongst other things. At the point of being plucked off the plant, fresh tea leaves are chemically alike, and contain about 3% caffeine molecules of total leaf weight. It is also correct that in the literature (ref “Tea: the Plant and its Manufacture; Chemistry and Consumption of the beverage” by Balentine, Harbowy and Graham) it is stated that oxidation increases the ease with which caffeine becomes water soluble. However, they also state that “The increase in caffeine level during the withering process can exceed 20%”. We have seen this general pattern to be true in our own teas that we’ve had tested. Our best-selling white tea yields less caffeine per serving than our best-selling green tea, and our best-selling black tea yields about 4.5 times as much caffeine per serving than the white. (These tests were run by a local food lab, and measures caffeine infused after 3 minutes of steeping time.)
With respect to stating that adding white tea to one’s diet will cause weight loss with all other factors being stable… if someone’s in calorie-overload, and gaining weight, just adding white tea to their diet will probably not cause them to lose weight. And yes, the points we make re appetite suppression and adipoogenesis have been researched and published. We’re delighted to be actively following new findings and sharing information from published scientific studies, with the hope of inspiring our readers into further investigation on the topic.
Maria, I am hugely impressed that you’ve had your teas tested at a local lab. That instantly vaults you into the stratosphere in terms of conscientious tea companies in the US. I’ll definitely be learning everything I can about your company over the next week. There are very few people doing more than repeating what they’ve read. Conducting your own real research….. bravo!
In your test of your best selling teas, you said that you used 3 minutes of steeping time for each… what was the water temperature? And was it the same for each type of tea?
I concur that there are a lot of variables to caffeine content. One significant variable is which leaf is used. The 2001 Chinese Study by Yang Weili found Silver Needles to have 6.1% caffeine by weight and Shoumei only 3.8%. I’m curious, when you say your best white tea, which style was this? Because withering does change caffeine content, and some white teas undergo significant withering and others almost none, any blanket statements become questionable.
As for the weight loss findings, my information and research matches yours, I’m just personally bothered by the inconsistency (which has nothing to do with you). For example, The USDA said it this way: “…until we do a really comprehensive study in which we have humans drink tea and see whether they lose weight, we can’t actually say that green tea makes people lose weight. What we can say is that it raises metabolic rates and increases fat oxidation rates. Those are two things that are predictive of weight loss.” I’m ready for someone to do this study and get it over with! :) You would think that for as much money as there is in weight loss and as long as we’ve been discussing this someone would have a better answer.
Love the discussion. Thanks.
Thank you Charles – and yes, we too would be quite excited to see a quantified metabolic rate boost parameter associated with a measurable compound in tea. I’m sure you’ve witnessed the teas that have made a market for themselves based purely on weight-loss claims…
Even more anxiously, I’m looking forward to the day when there are recommended minimum daily requirements for polyphenol antioxidants established by the FDA. Wrt testing and nutritional claims in teas today, however, it can be quite misleading – every number/test I’ve seen thus far measures the tea leaf to extraction. But that’s not what’s actually in the beverage in bottle you’re buying, or how most companies recommend their product be steeped. But none of us actually recommend the tea leaf be consumed when preparing the infusion, (except in the case of Matcha?) so those numbers don’t really pertain to the end product… I’m hopeful we’ll all see the day soon when nutritional claims and guidelines for tea are standardized.
Maria and Charles, thank you for the informative and stimulating discussion. I wrote 2 posts related to this topic in the past year or so. You can read the first one on green teas effects on weight loss and the second one which related to new research on white tea and weight loss. I have only a few comments to add.
1. Charles, asking your question why shouldn’t we expect a decrease in weight if all other factors remained constant and just white tea was added to a person’s diet is a good one. I think there are 2 issues that need to be considered here. Firstly, I don’t know if the effects that are being seen are that significant to have a real life impact on weight loss in and of themselves. It obviously would also be impacted by the amount of white tea that was being drunk. Secondly, and probably most importantly, is that most, if not all, of these studies were done in-vitro. We can certainly extrapolate to a certain extent what effects we would expect, but when it actually comes down to looking at the effects that substances have within the complexities of the human body, the reality can be an entirely different thing.
2. I have to agree with Charles about the issue of caffeine content in the dry leaf. Everything that I have read indicates that the new buds, because of the chemical processes created by the plant to protect the new buds and leafs from destruction from pests, contain the highest concentrations of polyphenols and caffeine. I don’t know why those compounds would be infused any less from white tea than any other type. In addition, I would want some clarification as to whether we are talking about the amount that is infused in the first cup of brewed tea, or the total from subsequent steeps as well. From what I have read, and from our own research that we conducted with a chemist from the Univ. of North Carolina, EGCG extracted fairly evenly, percentage wise, with each steeping. Caffeine, interestingly, was extracted in higher amounts in the 2nd and 3rd steepings than in the first, probably due to the longer steeping times. So, Maria, if you are talking about people just doing one steeping of white tea, than you assertion would fit. If, on the other hand, we are talking about total steepings, then I don’t believe that would be the case. Just as a caveat, however, the water temperature used in our study was much lower than normal for green tea. I’m sure with hotter temperatures the percentages would change to a certain degree, but I don’t think it would change the fact that the majority of both compounds still remains after the first steeping to be extracted in subsequent ones.
3. Both of you mentioned that white tea acts as an appetite suppressant. I would very much like to know the references on that. The only possible association I came across when I was writing my articles was the effect that white tea has on Leptin (the substance in the body that suppresses appetite), but it was related to Leptin’s role in angiogenesis and the impact that has on fat cells. If you could provide references I would appreciate it.
4. Maria – be careful what you wish for. Your desire to someday see tea standardized can be a double edged sword. This has been a long standing controversy in the herbal medicine community for a very long time. One potential problem with standardization is that you get researchers and manufacturers determining what they believe should be the most important compound to use as a marker for standardization. In the case of tea, my guess is that it will be EGCG based on all the research being done on it. As a result, you will start seeing tea farmers and scientist concentrating their efforts to develop strains/clones of tea that will meet those standards. What often occurs under these circumstances, is that although you get the standardized levels of EGCG showing up in the teas when tested, you don’t necessarily know what levels you are getting with any of the myriad other compounds contained in tea. And as has been the case over and over again throughout the years, we continue to learn that none of us are smart enough to trump mother nature. Tea, as any botanical with physiologically active compounds, is made up of countless other physiologically active constituents working synergistically to create the healthy effects we enjoy. When you start manipulating that for standardization or any other reason, you often change the end result. I remember many years back when St. John’s Wort became the new darling for the natural treatment of depression. All the manufacturers were leaping onto the bandwagon to show that their products were standardized to a certain percentage of Hypericin which was determined to be the active compound in SJW. This was the standard for years. It turned out later that they decided Hypercin, in fact, wasn’t the most active compound. Now it was Hyperforin that was identified to be the active compound and now they weren’t even sure how active Hypericin was. Then there was a mad rush for manufacturers to standardize to Hyperforin which was the marker for years. Since then, most manufacturers now standardize to both, just to be on the safe side.
All the science and in-vitro studies aside, in the 12 years I have been introducing white & green teas to my clients, the one consistent thread that I get as feedback on is that after a few months of drinking 2-3 cups of white or green tea a day, the average person will loose 1-1.5 pounds of weight a month. This has been relayed to me by more then a dozen people over the last decade. I usually inquire as to what else they are doing to achieve this weight loss, and most say nothing has changed in their lifestyle accept the addition of the above mentioned beverage.
So, the very first point in the article challenges me, because I have witnessed (from my tea sipping converts) the opposite.
As a result of this, I am fine with telling people that just by drinking 2-3 cups of green tea a day, you could potentially loose up to 1.5 pounds of weight per month.
The science behind this is something you guys can debate for eternity.
Great discussion though folks!
Not to make this any longer than it needs to go, but comes the continued dialogue…
Re white tea/weight loss: Indeed, the research we reference on white tea/weight loss was based on in-vitro lab studies. (Ref: Research & Development, Research Special Skincare, Beiersdorf AG, Unnastrasse 48, 20245 Hamburg, Germany “White Tea extract induces lipolytic activity and inhibits adipogenesis in human subcutaneous (pre)-adipocytes”). And Sandy, reference on white tea/appetite suppression recall may be in the nutritional study by Shari Lieberman in Alternative and Complementary Therapies, December 2003, “Natural Methods for Accelerating Weight Loss: The Low Glycemic Index Diet, Green Tea, Chromium, and 5-Hydroxytryptophan”
And wrt caffeine – yes, my generalizations are all based on only ONE (first) steeping quantity of caffeine measured in the infusion, NOT in the dry leaf.
Good point, Sandy, re standardization and having and arbitrary choice of which polyphenol(s) is most important to call out… as we know, all teas have different types of benefits. My point was more one of wishing to see some standardization on how the product claims are arrived at – for example, are the values stated for taking the food product to full extraction, or infusing as per the directions.