Would someone be able to compare the benefits of Rooibos Tea versus Green Tea?
Are they basically the same?
My primary areas of concern are the effects fo teas on cholestoerol levels.
Suggestions or comments?
Thanks,
Tmuld.
Would someone be able to compare the benefits of Rooibos Tea versus Green Tea?
Are they basically the same?
My primary areas of concern are the effects fo teas on cholestoerol levels.
Suggestions or comments?
Thanks,
Tmuld.
Green tea has been more extensively studied. There are epidemiological studies of green tea consumption correlating with protection against cancer.
Rooibos contains many polyphenols that are thought to be antioxidants and MAY prevent disease, but as of yet I have read of no epidemiological studies.
I have no idea.
Warning against taking "studies" too seriously.
I always shrug a bit every time I hear the word "studies". I also believe that public in general has very little idea what does that word actually mean, mean to mean, suppose to mean, etc. And the level of trust to such 'studies" is mind-boggling. Actually when my daughter many years ago asked my why formal scientific and math education was so important I said - first to maintain a healthy body of educated voters to protect the country against tyranny and second - to be able to evaluate the avalanche of marketing garbage that is sold to the public under the shield of the word "study".
Sadly, almost any attempt to ask a question combined with an answer can be called a study. A survey not unlike the one that we had here about tea can be called a study too. Every time a serious person say 'study" he or she must at least give the reference of it. A study then can be evaluated on its merits, or by the reputation of the journal that published it or a University that allowed to attach its name to it or an individual scientist that was a leading person or government body that regulated it. Spensors of the study must also be revealed.
A phrase " studies of green tea consumption correlating with protection against cancer" is misleading at best. First the word "protection" is a very strong word. It means that the study actually involved deliberate infection (or inducing) of the human subject with cancer (if it does not say animal study it implies human). I do not think so. Green tea consumption may correlate with reduced cancer incidence, but "protection"? Sorry. Second, such claims, unless it is narrowed to a certain type of cancer or a type of tumor is way too broad to be anything but just a statistical :"study". I am a firm believer of healthy benefits of tea and I do believe that tea in general and probably green tea more that others can be a factor of reducing the suseptability to matlignant tumor development. But to claim "protection", especially against a condition such as cancer.... one has to do a lottle more than "epidemiological studies"
Sasha.
Um, Sasha...epidemiological studies are how many human disease studies are DONE. Following groups of people and trying to see if there are connections that may have caused or contributed to a disease or freedom from a disease are one of the main ways research is done in these areas. It is not laboratory scientifically exact (you're a chemist aren't you? ;) ) but it is useful to a large degree..for instance, thalidimide victims. I agree that some scientists, if they cherry pick their subjects, can skew results to fit what they may want. But one shouldn't just toss the whole method if it has in fact been useful and life saving in the past.
I think they've done animal studies where they have induced cancer and then used green tea to fight it and see the results. Had to do with skin cancer though.
For your further researching enjoyment, here is a list of articles having to do with green tea and cancer (and a couple about cholesterol) that it took all of 20 minutes to look up via my local library, online. Libraries are wonderful places ya know. It would be better for the person looking for info about green tea and cholesterol to do some real reasearch instead of just asking all and sundry on a newsgroup...one can sift one's information and especially its sources much better that way. Google is OK as long as a person actually discriminates about where their info is coming from, or where it appears to come from.
1) Cancer Weekly, August 26, 2003 p47 Green tea's cancer-fighting allure becomes more potent. 2003 AUG 26 - (NewsRx.com & NewsRx.net) -- Green tea's ability to fight cancer is even more potent and varied than scientists suspected, say researchers who have discovered that chemicals in green tea shut down one of the key molecules that tobacco relies upon to cause cancer. It's a find that could help explain why people who drink green tea are less likely to develop cancer. 2) Alternative Medicine Review, Oct 2002 v7 i5 p429(1) Green tea inhibits vascular endothelial growth factor (VEGF) induction in human breast cancer cells. (Abstracts). (Brief Article) MR Sartippour; ZM Shao; D Heber. Sartippour MR, Shao ZM, Heber D, et al. J Nutr 2002;132:2307-2311. Investigators have shown that green tea and its main catechin epigallocatechin-3 gallate (EGCG) may decrease the risk of cancer. 3) Alternative Medicine Review, Oct 2002 v7 i5 p431(1) Suppression of human pancreatic carcinoma cell growth and invasion by epigallocatechin-3-gallate. (Abstracts). (Brief Article) M Takada; Y Nakamura; T Koizumi. Takada M, Nakamura Y, Koizumi T, et al. Pancreas 2002;25:45-48. INTRODUCTION: The consumption of green tea is associated with a lower risk of several types of human carcinomas. 4) Alternative Medicine Review, Dec 2001 v6 i6 p619(1) Green tea constituent (-)-epigallocatechin-3-gallate inhibits topoisomerase I activity in human colon carcinoma cells. (Abstract) DNA topoisomerases I and II are essential for cell survival and play critical roles in DNA metabolism and structure. 5) Journal of the American Dietetic Association, Oct 2001 v101 i10 p1278 THE NEW ENGLAND JOURNAL OF MEDICINE. (Brief Article) Full Text: COPYRIGHT 2001 American Dietetic Association Vol 344, March 1, 2001OK, that's enough for now. Sure a lot of stuff on green tea though. Your library is your friend..;)
Clarification:
The thing about "Your library is your friend" wasn't directed at you by the way Alex...it was directed to those who for one reason or another are not wanting or able to use their local academic resources and get better info then they might just Googling it and trusting to all the Wow web sites that ARE trying to sell them stuff. It is very much buyer beware out there these days.
Melinda
I agree with you completely when the language like "prevention" is used. "Protection" is a completely different issue. Epidemiological studies are statistical studies, while protection studies are experimental ones. I'll give you an example. let us say certain percent of the general population wear Kevlar armor under their shirts all the time ( a lingerie fashion statement perhaps. We can find during the study the incidences of damage by gunfire among general population that Kevlar armor definitely has a role in diminishing such damage. But to claim protection we have to try to shoot through it using different guns, ammo , distances and angles. After that we can say that Kevlar armor of such and such manufacturer and model protect from such and such projectiles at such and such angles, etc.
My degree is in geology, geochemistry and petrology but for many years I do math genetics and pharmaceutical applications in immunology and virology. Sasha.
Unless you use the word "protection" in a way that it ordinarily isn't used.
Bullet-proof vests protect against being shot. That doesn't mean you still couldn't be killed wearing one, that the body armor couldn't be defeated in various ways.
You are right, though. There's a simple minded mentality that could easily twist around scientific tidbits like that, and draw the wrong conclusions from the headlines you often get in papers and magazines.
What's a "statistical study"? I think you mean "observational", Sasha. And the first thing the discipline of statistics would tell you is that an experiment (where you change something and see what happens) is generally more informative than mere observation. To me the most valid (probably the only valid) way to get information on tea and health is to do a randomized clinical experiment. By "clinical" I mean on people, not rats or cells in petri dishes.
Here's what medline has to say about "randomized" and "tea" (after screening out lab studies, trials of tooth whitening agents, reports of worm infestation in Bangladeshi tea pluckers, and investigations into applying tea bags to nursing mothers' sore nipples. It isn't complete, just a summary of some studies which appear valid from my reading of their abstracts:
Oolong tea seems to lower blood sugar in adult-onset diabetics.
Black tea lowered LDL cholesterol in a crossover (self-controlled) study.
Similar results using an enriched green tea extract (phoo - I want to drink it, not refine it).
"Mixed tea" (iced tea from a mix?) did not appear to keep oral lesions from becoming malignant.
Oolong tea increased men's metabolic rate (but caffeinated water worked better).
Black tea helped open partially blocked arteries, while caffeinated water had no such effect.
Black tea did not help keep platelets from clumping in at-risk patients.
Black tea softened stool, but didn't do much else.
Green and black tea didn't change blood lipid levels.
(I would like to see a study on periodontal disease. My dentist now thinks I floss.)
Best,
Rick.
------------------------------------------------------------------------------- Rick Chappell, Ph.D. Professor, Dept. of Statistics and of Biostatistics & Medical Informatics, University of Wisconsin Medical School
600 Highland Avenue, K6/430 Madison, WI 53792 USA snipped-for-privacy@stat.wisc.edu Work (608) 263-5572 FAX 263-1059 Home 233-3664You should e-read my post again - that is why I said - protection could be claimed in that example only for certain angles, ammo, distances, etc. What you said does not contradict that at all.
Sasha.
Statistical study and observational study are not the same, but have similarities. Both work with "given" circumstances - nobody is being subjected to the disease or virus, etc. for the purpose of the study. People already had diabetes, tumors, etc. In observational study these people are studied individually, their level of sugar is measured, etc. In statistical study they may not be even contacted - the incidence of say, certain type of cancer will be checked against tea consumption statistics. Both studies can claim (with different degrees of precision and level of detail) the positive result, even to a certain degree - prevention. None can claim protection.
Again - to claim protection a healthy subject has to be infected or induced. The typical study would be a vaccine study, when a healthy subject will be inoculated with a vaccine and later infected with the virus. The level of protection will be determined by the dosage of vaccine, boosters (if any) and the dose of virus against which the subject would be protected. protection can also be full and partial (say a subject had a mild case of a disease instead of say, lethal, if he should not be inoculated). A certain vaccine may NOT be protective, but still useful, as it avoid lethal or disastrous result.
Another type of study with vaccines can be done on subjects that are already sick. Then, a vaccine may show THERAPEUTIC effect. That means that it will help heal or cure an existing disease, but may or may not protect against it. Same way a protective vaccine may not be therapeutic.
If anyone claims that the study yielded the PROTECTION against CANCER, (not prevention, not beneficial influence, not therapeutical effect) than a healthy subject that was treated with a protective agent has to subjected to a procedure that would make him normally a cancer patient. if no such attempt was made, no protection claims can be made.
Sasha.
There have been more clinical trials of tea than just the ones you mention... in fact too many to mention, along with epidemiological studies.
My point is... I've seen alot of health claims about Rooibos (usually people peddling it on the net, or in product packaging), but I haven't seen any clinical trial or epidemiological study abstracts. It does have compounds thought to be antioxidants, but epidemiological studies and clinical trials are the only good evidence.
Case in point- wine. Wine has antioxidants in it. You think you would see reduced cancer among wine drinkers, but when you look at epidemiological studies, you find the exact opposite- where there is heavy wine and alcohol consumption, there is also increase in cancer mortality (when adjusted for other confounding factors, such as fruit consumption), particularly cancers of the head, neck, and breast (note, wine does decrease heart disease risk... but increases cancer risk, most people are more likely to die of a heart attack, though, than cancer). This is because alcohol, in itself, is thought to promote cancer (and thus tea is a far safer way to get anti-oxidants, generally speaking). Not to mention that drunk drivers kill several thousand people a year.
Check out this link.
Rooibos has about half the total polyphenols (antioxidants) of tea (Camelia sinensis). Nevertheless, some of the antioxidants might be more powerful than the ones in tea. In a test involving injecting rats with a tumor promoter to measure the cancer protecting qualities, green tea and rooibos had similar levels of protection (but note, this is just an animal experiment and has limitations).
As this particular paper concludes, more research is needed. On the positive side, rooibos has no caffeine, which means it won't interfere with sleep or cause jitteriness (in fact it is apparrently a folk remedy for insomnia, though I doubt it causes drowsiness, in my experience- more likely it's just a coffee/tea alternative). Also, unlike green tea, it has very little tannins, so you can steep it as long as you want, whereas typically green tea is only steeped 1-3 minutes before it becomes overwhelmingly bitter.
I drink it often at night when I want to get some sleep and I don't want tea or coffee. It is also great to drink some first thing in the morning, because I find that tea on an empty stomach in the morning makes me a bit sick feeling. It has an interesting taste, though I wouldn't say it has much body to it, to me the aroma and flavor seem to be like pine needles. I usually drink it with a little sugar and honey- it's not bitter but the honey adds a little body to the flavor.
magnulus wrote in reply to my long post beginning:
RC> Here's what medline has to say about "randomized" and "tea"
M> There have been more clinical trials of tea than just the ones you M> mention... in fact too many to mention, along with epidemiological studies.
First, you're surely right that my list wasn't complete. But second, there may be fewer clinical trials than you may think. A lot of news stories and even journal articles speak of "trials" which then turn out to be epidemiologic (observational) studies. The problem with these is that green tea drinkers may be less likely to hang out on street corners smoking cigarettes, drinking cheap Wisconsin wine, and eating large numbers of pelmenis with sour cream. And then many of the trials which actually randomized people measured "antioxidant" levels in the blood stream or other similarly tenuous outcomes. The problem is that the country which has done the most research (Japan) is notorious for sloppy medical research methods.
(And Sasha, though I love many of your posts, I maintain that your definition of "statistical study" is gibberish.)
Best,
Rick.
Which is fine as long as you argue your point, you know, with ARGUMENTS.
Sasha.
Oh dear...that is a bummer since they'd be the ones most invested in finding out what good there is in tea healthwise. Didn't know that, thanks Rick. BTW, and not to be a pain, but how do you know Japan is sloppy? I.e. is there a statement or paper or something somewhere? Seems really weird that a country that's so technically savy would be sloppy in the lab...thanks again.
Melinda
Mel> Oh dear...that is a bummer since they'd be the ones most invested in
I should have been more specific and criticized their clinical research (on people), as opposed to medical research in general. And no, I don't know of any paper which says that Japan has rotten research methods, it is just based on personal experience based on the quality of their papers and the qualifications of people who have jobs which in the West would be filled by experienced statisticians.
Best,
Rick.
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