Talk:Health effects of tea/Archive 1

Article origin

The original text of this article was cut out of the green tea article. For history of the original text see the green tea history. --Oska 01:21, Jul 12, 2004 (UTC)

Source

The source for my recent addition regarding metabolism is Scienceagogo.com 1999

Sam [Spade] 19:44, 7 Aug 2004 (UTC)

Sources change a reference

The reference 37 on the Tripod server is not available anymore (BBC News | Health | Cuppa a day is a lifesaver). I did a research since it comes from BBC News and found the page directly from the source: http://news.bbc.co.uk/2/hi/health/208097.stm —Preceding unsigned comment added by 74.59.225.35 (talk) 08:35, 8 December 2010 (UTC)

Detailed Greentealovers reference

• greentealovers.com/greenteahealthcatechin.htm The Ingredients In Green Tea.
• greentealovers.com/greenteahealthcancer.htm Effects of green tea on cancer and the studies on Green Tea and their effect on various cancers.]
• greentealovers.com/greenteahealthotherconditions.htm Research on the effects of green tea on a variety of health issues: heart, pancrease, brain, kidney, circulation, strokes, anti-oxidant/inflammatory/bacterial/viral properties of green tea.]
• greentealovers.com/greenteahealthwhitetea.htm Research on the effects of white tea on a variety of health issues: Colon, Skin and its Antiviral/Antibacterial properties.
• greentealovers.com/greenteahealthdietweightloss.htm Studies on green tea's effects on weight loss, cholesterol, body weight, increases in metabolism.]
• greentealovers.com/greenteahealthantioxidants.htm The Antioxidant properties of Green Tea.

I think it is better if direct references to the original authors work are put rather than to Green Tea Lovers, because journal references do not move with time. It would be better if someone with knowledge on the subject did this to select the best that suit the article? --Iateasquirrel 17:30, 5 March 2006 (UTC)

I think the links to Greentealovers should be removed. How is a tea dealer's website an acceptable reference source about the health benefits of tea? Even if they accurately summarized some scientific studies, how do we know aren't cherry picking them? The links in the article look suspiciously more like search engine optimization than references at the moment. And a glance at a non-commercial site, which also cites scientific studies, paints a considerably more ambiguous picture about the health benefits of tea. —Veyklevar 09:19, 14 April 2006 (UTC)

Health Effects Tilted Towards Drawbacks

The fluoride and caffeine entries in the "Potential Health Drawbacks" could also be placed in the potential health benefits category, since both of these compounds have both positive and negative effects. It might be best to just combine both the benefits and the drawbacks sections into one, detailing each category and its positive and negative effects for a total view of the health effects. 72.219.189.102 (talk) 22:54, 10 February 2013 (UTC)

I agree with that. It seem like an inapt bias. Fluoride is deemed so important for teeth and bone health that some countries like the US even introduced it into their public water supply. Green tea may be an important and beneficial source of fluoride especially in those countries who don't have fluoridated water. 92.229.176.79 (talk) 09:30, 14 May 2013 (UTC)

Plaguarism?

I copied and pasted a few paragraphs from this article into google, and it seems that large portion of this article is pretty much an exact copy of an article from the June 1999 Life Extension magazine, which was reprinted here Is this okay? --Cabazon 05:04, 5 January 2006 (UTC)

No, that's not okay. We need to revert the article to before the point where the copyrighted material was inserted, if anybody can figure out where that is. —Veyklevar 06:28, 13 April 2006 (UTC)

As far as I can tell we would have to revert it to about this version to avoid copyright problems. Would anyone like to double-check me on that before I make such a major change? I don't think it's such a big loss since large portions of this article as it stands now read like advertisements. —Veyklevar 08:56, 14 April 2006 (UTC)

Complete silence. Well either everyone agrees with me, or I'm the only person who reads this article. I'm going to proceed with reversion. —Veyklevar 01:00, 21 April 2006 (UTC)

I agree. I've kind of given up with the article, until Wikipedia has some strong "stable version" feature. It's such a magnet for spam and misinformation. Thanks for the revert. --Wikimol 08:38, 21 April 2006 (UTC)

Does anyone find the vandalism here?

Sugar?

Since there's a section on the effect of milk on tea, shouldn't there be one on the effect of sugar on tea? or have there not been any studies done on that?--69.120.63.248 03:37, 15 January 2007 (UTC)

Milk was mentioned because it is a very complex substance that has been found to interact with components of tea due to certain chemicals such as casein which are present. Sugar has not been shown to chemically alter the contents of tea, as it does not engage in a significant chemical reaction with tea in the way that milk does. A small amount of milk added to regular tea exhibits visible coagulation and alteration of the physical appearance of the tea, whereas sugar does not. 24.65.42.159 (talk) 00:59, 4 July 2008 (UTC)

Like Excellent response. (Heroeswithmetaphors) talk 14:58, 9 November 2012 (UTC)

Milk

The milk section is filled with unverified claims, and desperately needs the attention of an expert. I personally thought that the casein was thought to bind with the tannins, and did not have an effect on the EGCG, but I do not have a source on hand. —Preceding unsigned comment added by 24.65.42.159 (talk) 01:01, 4 July 2008 (UTC)

Move page to "Potential health effects of tea"

Why I think the page should be moved: #1. Many effects are still being researched, evidence is not yet conclusive, so we should emphasis that the effects are not yet certain. Secondly, there seem to be a few drawbacks associated with drinking tea, such as a reduced iron intake (which can be quite harmful for people with an already low iron blood level. I think it isn't a good idea to create a separate page for these disadvantages. Sijo Ripa 14:44, 2 February 2007 (UTC)

• I agree Abtract 18:04, 2 February 2007 (UTC)
• Disagree The page is about health effects. Virtually everything humans consume have health effects and the effects are there, whether or not they're known. In the case of tea, some of the effects are relatively better-known (as with the effects of caffeine), whereas many are poorly-understood (as with many of the effects of tea on cancer risks and other potential benefits, or the very complex positive and negative effects of tannins and their interactions with other substances), or totally unknown (as with the effects of many of the more specialized compounds only occuring in certain types of tea, and many interactions of more basic substances, even caffeine). Calling it "Potential" seems to introduce POV (and I would say is outright wrong--because Tea obviously has effects on health, it's just that these effects are not fully understood). Some of the theorized effects of tea on health fall solidly into the "potential" realm...and I think it's better to use the word "potential" in these cases (i.e. when the use of the word is backed up by reliable sources. Cazort (talk) 21:02, 3 September 2009 (UTC)

Latest findings on theanine

I added info and link to Sept. '07 announcement regarding latest findings on theanine and its influence on alpha brain-waves. Balance2214 21:51, 20 September 2007 (UTC)

== Preventing HIV == This section could be seen as an overstatement. Oka6 (talk) 21:48, 17 March 2018 (UTC)OKA6

How do you prevent HIV through a strong immune system? I mean, if you have the virus, you've got it. The tea won't come and delete the virus. Does the sentence actually mean it can prevent Aids? Or how does it then prevent HIV? — Adriaan (T★C) 10:25, 6 December 2007 (UTC)

I'm sure you know that no cure for HIV exists. Once you have it, you'll die with it. But 'having HIV' is defined by having a certain count of the virus in your system (or more precisely, by T cell count, which is a proxy for virus count). 'Prevent' HIV infection is what the source claims, which by definition means stopping a healthy system from becoming infected, not making an HIV-positive(i.e. thoroughly infected) person healthy again. Our immune system is capable of destroying small amounts of the HIV virus, by the normal mechanism that it defeats e.g. the common cold. A stronger immune system will be able to fight off higher counts of the virus before being overwhelmed and infected. Not that I actually believe that tea is effective in preventing HIV, I'm just explaining why the section accurately describes the source's claim.-₪-Hemidemisemiquaver (talk) 11:22, 6 December 2007 (UTC)

I agree the statement is very poorly worded. It gives the reader the impression that tea can act to prevent HIV. Which is compeltely absurd.JHJPDJKDKHI! (talk) 04:01, 10 December 2007 (UTC)

Agree, but as long as the article is worded "A 2007 Study by X found that..." and the study isn't total crackpot, it describes reality.-₪-Hemidemisemiquaver (talk) 17:23, 10 December 2007 (UTC)

Statement seems abit false

"A recent study appearing in the Journal of Allergy and Clinical Immunology stated that epigallocatechin gallate (EGCG) found in Green Tea can help to boost one's immune system, therefore helping to prevent HIV"

Surely they're not suggesting tea can prevent HIV, but rather slow down progress toward AIDS.JHJPDJKDKHI! (talk) 04:00, 10 December 2007 (UTC)

see the thread above this. The study is cited (it was cited via a news article, going to add the cite to the actual study) and its claims are more or less accurately described, though the study is less about strengthening the immune system than protecting the immune system cells by competing for the same binding sites on cells that HIV uses. It may not be true, but it certainly meets WP:RS. 'Preventing HIV' is relative, and anything that reduces the likelihood of binding to T-cells will in theory both reduce the spread rate and increase the watershed virus count before full infection. Certainly it is possible for the immune system to completely defeat a very small number of HIV in your system. If, hypothetically, two identical people were going to be infected with two identical very small amounts of identical HIV virus which was marginally above the level that would infect that person, the paper conjectures that if one took megadoses of EGCG prior to infection, it's possible (according to the study) that he might not contract HIV while his counterpart would. Dicey claims, yes, but it's cited, and debates over plausibility are original research.-₪-Hemidemisemiquaver (talk) 17:52, 10 December 2007 (UTC)

This statement is not completely true

On the effects of tea and antiretrovirals on HIV, the article states ART (antiretroviral therapy) drugs cannot cross the blood-brain barrier. Many indeed cannot, but the non-nucleoside reverse transcriptase inhibitors (NNRTIs) do cross the blood-brain barrier. In fact, that's why Sustiva causes vivid dreams and psychological side effects — it readily penetrates brain and spinal fluid. So this statement needs to be qualified, e.g., "most antiretroviral drugs cannot cross the blood-brain barrier, except NNRTIs, which easily penetrate the barrier". Kinkyturnip (talk) 00:56, 13 June 2008 (UTC)

Green tea lowers testosterone

I'm raging right now, lol, on the article page I pressed Ctrl+F and tried searching the word "testosterone" and there's not a single mention of it. (Google test or whatever you call it gives 419 000 results for "green tea testosterone"). I'm determined to write about it but I remember that some time ago there was info in Wikipedia about testosterone-lowering effects of green tea, perhaps someone has just removed the info and it should just be recovered because quite frankly I'm not sure I could write anything by the standards of an article... Lysis rationale (talk) 15:31, 24 June 2008 (UTC)

I just did a search of the scholarly literature and was unable to find a single article backing up this claim that Green tea lowers testosterone. The only hits I find in google are on internet forums and even then, they seem to be discussing this as a myth or misconception. Cazort (talk) 00:53, 15 February 2009 (UTC)

There is this rat study: http://jn.nutrition.org/cgi/content/full/138/11/2156

84.39.105.143 (talk) 03:21, 10 September 2010 (UTC)

This article is not encyclopedic at all

It's a list of claims from some scientific and some not articles that are not accepted as valid in the scientific community. Most of these reports that are cited in here are inaccurate, unverified, or outright false. Very disappointing that people are amassing any trash they find on the web into wiki. So tea is great, it prevents cancer, reduces stress, oh my... —Preceding unsigned comment added by 128.12.172.11 (talk) 23:50, 6 September 2008 (UTC)

Get on google scholar. See this search: [1]. No need to rely on junk web reports or even popular science magazines or web articles...plenty of really good scientific research out there. Cazort (talk) 19:17, 17 August 2009 (UTC)

Negative effects on human health

One of non-English Wikipedia articles on tea states that aluminium and fluorine in tea may cause cancer. It also says that coffeine in tea dries the skin and makes it look older if consumed often. Could anyone competent refer to this? —Preceding unsigned comment added by 78.131.137.50 (talk) 17:30, 26 November 2008 (UTC)

The line "there is a substantial body of evidence that excessive aluminum intake may lead to Alzheimer's Disease" is wrong in the sense that there is just as much evidence that aluminum intake is unrelated to Alzheimers. The Alzheimer's Association website calls it a myth. A 2002 review of the evidence by Rondeau in the Review of Environmental Health said that the evidence was inconclusive. Aljo99 19:21, 5 January 2012 (UTC) — Preceding unsigned comment added by Aljo99 (talk • contribs)

Overall tone of article: POV?

It is my understanding from reading a pretty broad variety of articles on this topic that there's a scientific consensus that tea is generally beneficial. The debate in the scientific literature seems to center around which ways in which tea is beneficial--not whether it is beneficial. The way the text is written on this page is inherently misleading; the text currently reads: "The possible beneficial health effects of tea consumption have been suggested and supported by some studies, but others have found no beneficial effects". This is misleading--it is true that some studies have not found/confirmed any beneficial effects of tea...however, many other studies have. And, I haven't read a single study where the authors have strongly questioned whether tea has any beneficial properties. For example, this abstract: [2] reads "Experimental studies have demonstrated the significant antimutagenic and anticlastogenic effects of both green and black tea and its polyphenols in multiple mutational assays." This is a pretty strong and clear-cut statement. This abstract: [3] reads: "Among the health-promoting effects of tea and tea polyphenols, the cancer-chemopreventive effects in various animal model systems have been intensively investigated". Yes, there are plenty of studies that come back inconclusive, finding no strong evidence, or finding that it "may be beneficial". But I'm not finding anything strongly establishing that tea does not have beneficial properties. It seems to be pretty strongly established that it does--but that the exact extent of these properties is uncertain. Thoughts? Cazort (talk) 01:04, 15 February 2009 (UTC)

You don't read much then. Even in the telly the warn not to drink to much of tea, especially if you have high blood pressure. —Preceding unsigned comment added by 78.131.137.50 (talk) 03:45, 3 April 2009 (UTC)

Please back up your remarks with sources. I do read a lot, and I've found no scientific evidence that tea is bad to drink if you have high blood pressure. Don't believe everything you hear on television...we need to rely on high-quality scientific research here, preferably that published in reputable peer-reviewed journals. (See WP:RS) Some articles: [4] shows non-stastistically significant decrease in mortality related to heart disease, among tea drinkers (no increase in mortality!). This article: [5] finds some evidence that tea lowers blood pressure in older women. This study: [6] found that tea caused acute increases in blood pressure, but the results were not statistically significant, and also, they did not translate into any effects on ambulatory blood pressure, which is ultimately what matters most in the long run. Cazort (talk) 19:15, 17 August 2009 (UTC)ʔ

New page title

Instead of "Potential effects of tea on health," how about simply Tea and health just like Coffee and health? "Potential effects" makes it sound like we are making predictions, which we don't do on Wikipedia. 125.69.111.144 (talk) 08:36, 13 April 2009 (UTC)

Good point. Making the title NPOV is a good idea. -- BullRangifer (talk) 02:53, 14 April 2009 (UTC)

Yes, if the research on such a point is still so weak that any beneficial effects are seen as only potential, then Wikipedia shouldn't cite it. Martin Rundkvist (talk) 21:05, 3 September 2009 (UTC)

Does green tea have more or less fluoride?

I know fluoride levels vary according to soil, but, does green tea tend to have more or less fluoride?

The article says that fluoride varies inversely to EGCG, yet, it says that green tea has higher EGCG than white or black, which would suggest lower fluoride. But it says green and black tea have higher fluoride than white! And [7] website says green tea has the highest fluoride levels. Dranorter (talk) 03:40, 18 June 2009 (UTC)

Since Fluorine is an element, it seems unlikely that the processing differences for green, white, or black teas could result in changed fluoride levels. It will depend on the fluoride content of the original plant, which is largely determined by the soil in which it was grown.

EGCG and the blood-brain barrier

So, does EGCG (or other catechins) really cross the BBB? I found this paper, which says that the flavonol metabolites of green tea do not cross the BBB, so I added a "citation needed" sign next to the last sentence of point 1.6.

I also found two other papers, and if I understand them correctly, they say that EGCG inhibits the conversion of L-Dopa into Dopamin, among other things. So I imagine if EGCG would cross the BBB, it would have a rather depressing effect. Purposelessness (talk) 10:38, 12 January 2010 (UTC)

The stronger the brew, the more healthier it is

Although most tea drinkers want to ignore the evidence, (because they don't like bitter tea) the longer tea is brewed the more healthful properties it has. Numerous studies indicate this. For example: http://pubs.acs.org/doi/full/10.1021/jf070351y?cookieSet=1 Overbrewing tea makes it healthier. The bitterness is actually caused by increases in antioxidant capacity and total phenolic and catechin contents as well as caffeine. The so called tannins which some claim occur in overbrewed tea is in fact simply the concentrated tastes of these flavonoids. 201.230.1.89 (talk) 00:54, 16 February 2010 (UTC)

Few times a week optimal for brain

In 2010 researchers found that people who consumed tea had significantly less cognitive decline than non-tea drinkers. Study participants who drank tea 5-10 times/year, 1-3 times/month, 1-4 times/week, and 5+ times/week had average annual rates of decline 17%, 32%, 37%, and 26% lower, respectively, than non-tea drinkers. Coffee consumption did not show any effect except at the very highest level of consumption, where it was associated with significantly decreased decline of 20 percent. The study used data on more than 4,800 men and women aged 65 and older from the Cardiovascular Health Study to examine change in cognitive function over time. Study participants were followed for up to 14 years for naturally-occurring cognitive decline. (AAICAD 2010; Lenore Arab, PhD; UCLA[8])-71.174.187.200 (talk) 21:33, 12 July 2010 (UTC)

Diuretic and caffeine

I removed the section under Drawbacks Related To Caffeine about 300mg of caffeine being necessary for diuretic effects and that the British Dietetic Association endorses tea drinking for hydration, as this is all cited nearly verbatim from the British Tea Council and the Tea Advisory Council websites. I replaced from actual, much-less-definite claims from the BDA. I haven't found actual research studies on the diuretic effects of caffeine, however, and humbly request the aid of fellow editors who are not up past their bedtime. SamuelRiv (talk) 05:59, 3 August 2011 (UTC)

Health claims

Many of the individual tea articles have claims of beneficial health effects and sometimes contradictory; it would be great to centralize them here instead of riddled throughout the articles. icetea8 (talk) 14:40, 4 August 2011 (UTC)

Needs rewrite following MEDRS much closer

The article needs to be written from better sources than just individual studies, preferably systematic reviews and statements from relevant expert bodies. See WP:MEDRS for details. --Ronz (talk) 17:16, 24 November 2011 (UTC)

25 Liver Damage idiocy

To repeat what I said on the Tea discussion page:

The connection of Hydroxycut's reported side effects to the tea extract compound is irresponsible, and makes a claim that has no foundation or evidence: "liver damage, caused in part or completely by the presence of green tea extract in these supplements; the most notable cases include Hydroxycut[...]" Hydroxycut became popular first as a version of the bodybuilder's infamous trio: caffeine, ephedra, and Asprin: in this case guarana extract, ephedra extract, and white willow bark for the natural ASA. After ephedra was banned they switched to a blend of other popular ingredients: Garcinia cambogia, Gymnema sylvestre, chromium polynicotinate, caffeine, green tea- and Citrus Aurantium, which is inexplicably not mentioned in the Wikipedia article on Hydroxycut. The studies cited only attribute a causal association between liver failure and Hydroxycut as a whole: there is no reason to single out Camellia sinensis as the culprit- and given that tea is exponentially the most widely-used ingredient that happens to appear in that formula (excepting caffeine), the likelihood of the tea (a minor ingredient in the capsules)being the problem is almost nil. The Citrus Aurantium (Bitter Orange) peel, used as a source of synephrine to replace ephedrine, is the most likely culprit, coupled with excessive caffeine. Add in the new Hydroxycut Advanced, and you're talking about at least three different formulations of the product- and given the timeline, it's entirely possible that the liver failure cases were in customers who had NO tea in their capsules. Specifications per dose of Hydroxycut (2000mg):

  Guarana Extract....................910mg (containing caffeine)
  Citrus Aurantium....................300mg (containing synephrine)
  L-Carnitine.............................100mg (amino compound/quat)
  Salicin Complex.......................15mg (salicylate phytohormones)
  Chromium Picolinate..............300mg (niacin-bound chromium, a trace mineral).

In short, the Hydroxycut observations are misleading, have nothing to do with tea, and should be removed from the article. In fact, I'm doing it now, and until someone provides a shred of reputable evidence linking TEA (as a singular ingredient) with any cases of liver failure, it should stay out. 69.165.149.221 (talk) 12:24, 7 December 2011 (UTC)]

About the antioxidants

This article does mention that tea contains antioxidants - but aren't the antioxidants in tea known as "flavonoid antioxidants"? ACEOREVIVED (talk) 22:24, 9 February 2012 (UTC)

FDA statement in 2005

FDA finding is out of date and wrong, given these three studies that found consumption of green tea cuts the risk of getting ovarian and endometrial cancers, and advanced prostate cancer by 50%.

• "Coffee and Tea Consumption Are Associated With a Lower Incidence of Chronic Liver Disease in the United States". Retrieved 2012-03-11.
• "Green Tea Consumption and Prostate Cancer Risk in Japanese Men: A Prospective Study". Retrieved 2012-03-11.
• "Higher regular coffee and tea consumption is associated with reduced endometrial cancer risk - McCann - 2008 - International Journal of Cancer - Wiley Online Library". Retrieved 2012-03-11.

So I'm removing that paragraph.32cllou (talk) 02:21, 15 March 2012 (UTC)

Sorry, not according to WP:MEDRS. Primary studies do not trump "position statements from nationally or internationally recognised expert bodies." --Ronz (talk) 03:02, 15 March 2012 (UTC)

How about leaving the old FDA statement, but then qualifying it with the new research? Something like While the FDA in 2005 finds XYZ, these later rigorous (prospective double blind etc) studies found LMN. Did you read the research?, which looks like gold standard stuff. There's also a new study finds breast cancer recurrence is suppressed by green tea.32cllou (talk) 23:59, 15 March 2012 (UTC)

Qualifying the FDA statement with subsequent research would be WP:OR.

I skimmed the new research. Did I miss something, or are they all just primary studies? I didn't see anything more authoritative, nor did I see a definite conflict between the FDA statement and the research findings. --Ronz (talk) 01:10, 16 March 2012 (UTC)

They are all primary studies. I wouldn't qualify the 2005 FDA statement, though it's easy to question the FDA's focus. Health effects isn't the place for that dissertation.

I'm not qualified to do anything but reference. But isn't it good to write a paragraph after the FDA one simply noting that research in 2006 - 2012 finds this and that. There are many more than those three I provided, and for other cancers, but those are the three that seemed strongest and that I bought. Another really clean one (peer referred to as "gold standard") finding strong correlation between consumption of green tea and reduced breast cancer reoccurrence and metastasis. Random, prospective, high end institution stuff. Another editor showed me how to get research for free, so I'll pull together the paragraph unless you say it’s a waste of my time.32cllou (talk) 10:30, 16 March 2012 (UTC)

If we can't find anything but primary studies, we need to be careful. Eventually there will be reviews that will indicate any change in medical consensus, which we should then incorporate.

I'd like to see what you come up with. I don't think it would be waste of time even if it were later taken out completely. What I'd like to do is get some editors with more experience handling such situations - where the most current research findings suggest that medical consensus may change... --Ronz (talk) 18:34, 16 March 2012 (UTC)

I've reformatted 32cllou's references above so they appear as readable references, rather than footnote markers. Please revert if that's inappropriate. I can't support us synthesising the results of primary sources. Although some of those results look promising, we don't know how many other studies show a positive or non-existent correlation between tea consumption and cancer, and I for one don't have the skill required to properly assess the quality of the above studies. For these and other compelling reasons, and per WP:MEDRS, we should wait until an authoritative review contextualises all the recent research. --Anthonyhcole (talk) 01:51, 22 March 2012 (UTC)

I'll try to find overseas Authorities to use properly. Hopefully, they will cover a broad range of uses.32cllou (talk) 17:17, 22 March 2012 (UTC)

Green tea as medicine

Copied from my talk page.

I'll draw only from the NCI report (which cites some of the same primary studies) but conclude with "the evidence regarding the potential benefits of tea consumption in relation to cancer is inconclusive at present."32cllou (talk) 03:03, 22 March 2012 (UTC)

I can see no merit whatever in adding mentions of primary studies that contributed to that report's conclusions. And cherry-picking encouraging primary studies will only serve to undermine that report's main conclusion. --Anthonyhcole (talk) 03:41, 22 March 2012 (UTC)

End of copy from my talk page. --Anthonyhcole (talk) 03:41, 22 March 2012 (UTC)

I agree that using the NCI wouldn't work, mostly because they review so few studies. My original thought was to show both + and - research, then by citing peer reviews hint + is better. Too hard, and for most to understand. What's there now is sufficient.

Instead I'll draw from Asian FDA equivalent authorities. Most of the research finding medical uses for green tea come from abroad, especially Japan and China. I remember reading somewhere that green tea might work better than US prescription meds for type 2 diabetes ect from some Chinese authority. So far, I've found Europe only calling for papers. I'll search for an Authority overseas, and be back here with anything worthwhile.32cllou (talk) 17:10, 22 March 2012 (UTC)32cllou (talk) 17:11, 22 March 2012 (UTC)

what about Angiogenic Virtues?

as was demonstrated by Dr. William Li's research group- several types of tea have been highly effective in significantly reducing size of tumors. link to ted talk: http://www.ted.com/talks/william_li.html --Elads0 (talk) 13:13, 29 March 2012 (UTC)

Thank you for the link. Great content.

Some think primary research doesn't belong look above "I can't support us synthesising the results of primary sources. Although some of those results look promising, we don't know how many other studies show a positive or non-existent correlation between tea consumption and cancer, and I for one don't have the skill required to properly assess the quality of the above studies. For these and other compelling reasons, and per WP:MEDRS, we should wait until an authoritative review contextualises all the recent research. --Anthonyhcole (talk) 01:51, 22 March 2012 (UTC) He removed almost all of the health effects content and highlighted the FDA (saying NO VALUE) assuming they really studied the issues based on their title. The NIH or Medline http://www.nlm.nih.gov/medlineplus/druginfo/natural/960.html may meet his standards, but they mostly say "possibly" to such things except warts.32cllou (talk) 18:23, 30 March 2012 (UTC)

Yes. That is a great link. Thank you. Wow. I'm going to be living on cooked tomatoes, tea and aspirin from now on. (Actually I'm already on one aspirin a day.) Li reports the effect of tea on angiogenisis, not tumor growth, in a test tube.

The reason I stripped out the content based on primary sources was because, in simple terms, that's how Wikipedia works. The relevant guideline is WP:MEDRS. Basically, for health-related content we only report the findings and conclusions of expert reviews. That way we are most likely to be presenting the current expert opinion. When Wikipedia articles are based on a collection of primary sources (epidemiological studies, randomised control trials, in vitro studies, animal models, etc.) they are acting like a review, but a review written by anonymous authors, with no expert oversight, and quite likely no rigor. The down side of the guideline is we have to wait, sometimes quite a long time, before someone publishes an authoritative review. But it's the most responsible method anyone's come up with, so far, of ensuring we don't mislead. --Anthonyhcole (talk) 21:21, 30 March 2012 (UTC)

Blanking of sections

User:Anthonyhcole recently blanked a huge section of this article. Many of the sections blanked contained citations to peer-reviewed journal articles. In particular, I'm concerned that:

• In cases where specific individual studies are cited, rather than systematic reviews, I think it would be more constructive to actually locate and cite reviews and clean up the section, rather than just blanking the section.

• In cases where there is some specialized topic on which there are only a handful of studies, I think it would be more in keeping with Wikipedia's guidelines on WP:RS And WP:V to keep citation of these studies, but just take the limited nature of the evidence into account in the material we write in the article. Isolated studies cannot establish something as truth, but they can establish interesting facts like "A single study found X.", which I think enriches Wikipedia's articles on these topics, it helps it to be cutting edge without giving undue weight to these fringe results.

Cazort (talk) 16:32, 3 April 2012 (UTC)

I'm for simply following WP:MEDRS instead. Even without MEDRS, the selection of individual studies becomes a NPOV and SYN problem. --Ronz (talk) 19:09, 3 April 2012 (UTC)

The article seems empty and incomplete

The article barely has any mention of Tea's potential health effect. Tea has been associated with many health benefits, why aren't they mentioned in the article ? I'm sure there are plenty of reliable governmental or peer reviewed scientific sources that cover them, we just have to find them. As stated earlier you can find those easily on google scholar. See this search: [9]. I even wonder if the article should be considered as a Stub. --75.152.29.81 (talk) 01:13, 15 August 2012 (UTC)

See WP:MEDRS and the discussions above. The only expansion I can see possible is to try to find reliable, independent sources on the marketing and promotion of health claims, and carefully qualifying those claims against the actual medical consensus. --Ronz (talk) 17:00, 15 August 2012 (UTC)

Instead of just saying "see WP:MEDRS" every time someone attempts to add a citation regarding the potential health effects of tea, why don't you cite where in WP:MEDRS the editor needs to look. Moreover, as someone who is familiar with WP:MEDRS, I think you are reading it too literally, and it is impacting your ability to allow this article to be improved. Indeed, that is the intention of the editors here, and I do assume good faith. As such, I will continue to try to improve this article here. One issue that stands out: a statement by the FDA, which you claim is the only thing right now that is satisfactory about tea and cancer (which, as others have pointed out, considering the relaible resources available on this topic, is nonsense) from 2005 that mentions only two studies (primary studies) and includes a general note on research they have skimmed. Dated and general. But apparently that satisfies your criteria. Doesn't add much to the article or heading, though. Jimsteele9999 (talk) 12:06, 14 May 2013 (UTC)

Please WP:FOC.

As pointed out "Generally this means recent expert reviews in peer-reviewed scholarly journals, graduate-level text-books, national or international guidelines, etc."

At this point, I'm still concerned that the material is being added without regard to MEDRS. --Ronz (talk) 15:16, 14 May 2013 (UTC)

It seems we have an issue of NPOV here. I've tried to find some balance here but you appear, as it has been mentioned by others here, to want to list only the drawbacks and mention nothing about potential benefits re: cancer. There is no reason why my citations did not satisfy MEDRS. The citations under "anti-cancer effects" now are no different, besides being quite dated. And I say NPOV because this "However there is some positive evidence for risk reduction of breast, prostate, ovarian and endometrial cancers with green tea." seems to be missing from footnote 13, though apparently what you included is okay. Hmm.Jimsteele9999 (talk) 15:50, 14 May 2013 (UTC)

Redirect

I just gutted the section on green tea regarding health effects since the best MEDRS don't concretely support any benefits. I plan on, at some point, going through this article as well since it looks like there are still some primary source and original research issues lingering. However, the resulting page will probably be quite short, to the poin that it might be worth redirecting the page rather than leave a stub. The issue being there are two main types of tea. Possibly just redirec to tea? Which has its own, similar problems. WLU (t) (c) Wikipedia's rules:^simple/_complex 15:46, 15 November 2012 (UTC)

Potential benefits and Potential Drawbacks are mixed up

Fluoride should be listed as a Potential Benefit.Stubborn Myth (talk) 07:28, 13 February 2014 (UTC)

This comment hardly even qualifies as "talk." If you're going to assert something, you have to also provide a rationale. tripbeetle (talk) 13:49, 13 March 2014 (UTC)

Iron Absorption reduction by 65% ?

As per NYtimes article. Can some one verify and put it in the article ? — Preceding unsigned comment added by Vwalvekar (talk • contribs) 05:07, 19 June 2015 (UTC)

I have added the above section. Those who think it is poorly sourced, could you please explain ?... Source is a US govt website. — Preceding unsigned comment added by Vwalvekar (talk • contribs) 07:16, 19 June 2015 (UTC)

Please see WP:MEDRS. Sources for health information must be of the highest quality. Alexbrn (talk) 07:25, 19 June 2015 (UTC)

Is this claim of Iron Absorption reduction valid ? Can some one please provide a source that is acceptable ?... Apparently NIH source is not. — Preceding unsigned comment added by Vwalvekar (talk • contribs) 08:56, 19 June 2015 (UTC)

I have adding something using this source:

• Wierzejska R (2014). "Tea and health--a review of the current state of knowledge". Przegl Epidemiol (Review). 68 (3): 501–6, 595–9. PMID 25391016.

Alexbrn (talk) 09:21, 19 June 2015 (UTC)

I have reinstated the section since if reference is old does not mean wrong. If any one thinks if anything is wrong, please port your comment. — Preceding unsigned comment added by Vwalvekar (talk • contribs) 14:40, 2 July 2015 (UTC)

there is a review from 2014 in the article now. we don't use old primary sources when we have recent reviews. Jytdog (talk) 15:22, 2 July 2015 (UTC)

Conclusion on the relationship of tea and weight loss overstated

The current "Weight loss" section cites a single meta-analysis (Johnson, Bryant, Huntley) from 2012 and significantly alters its claim from acknowledging effects but characterizing them as "unlikely to have clinical significance" to a very strong, universal, positive claim of there being no meaningful role in "aiding weight loss". Alexbrn says "Plain is better", a notion I agree with, but not when it is plain to the point of being incorrect.

"Weight loss" is an ill-defined term for a very complex subject encompassing not only absolute loss of weight, but also fat oxidation, fat composition (white vs brown adipose tissue), total energy expenditure, modulation of energy expenditure or fat oxidation during exercise, etc. To state that tea has no meaningful effect on weight loss is to state tea has no impact on any of these on the scales humans would find relevant. Yet numerous other studies implicate tea (and tea extract) in exactly these, which along with being aligned with the effects acknowledged in Johnson, Bryant, Huntley (2012), brings it at odds with the current presentation.

While it may turn out that is it indeed hard to extract "meaningful" benefits from it, the issue is far from settled and it is fairly obvious that compounds in tea do have an active role on human metabolism. Moreover, the word "meaningful" is somewhat weaselish. It is also very likely there are numerous confounding and/or moderating factors which could explain the conflicting results attained in different studies. In this light, I do not see how cherrypicking one side of the argument is justified.

I am inclined to revert Alexbrn's revert since I feel strongly the current section grossly misrepresents the current research on this, but since I do not want to start an edit war, I request new opinions. From the edit history, I see that this exact issue already came up about a year ago, but it was similarly reverted without too much explanation. Even if my reverted edit is also deemed an inappropriate assessment, I think it would still be better to state nothing at all than to state a simplified falsehood.

Denis Kasak (talk) 14:26, 25 November 2016 (UTC)

References

According to our RS any effect is not clinically relevant (so in lay terms no meaningful). We reflect that RS. Alexbrn (talk) 14:32, 25 November 2016 (UTC)

In light of your recent edit, why does my previously cited article (which finds a dose-dependent effect of the caffeine-catechin combination on 24h energy expenditure and fat oxidation) or, for instance, this study (specifically dealing with weight loss and maintenance, finding a small but rather significant effect, P<0.001) not count as good evidence? Both studies are meta-analyses.

Regarding the adverse effects and hospitalization remark you added, I would like to point out that the resource you cited in support of it specifically state the following:

"In the eight studies that recorded adverse events, four reported adverse events that were mild to moderate, with the exception of two (green tea preparations group) that required hospitalisation (reported as not associated with the intervention)."

"Most adverse effects, such as nausea, constipation, abdominal discomfort and increased blood pressure, were judged to be mild to moderate and to be unrelated to the green tea or control intervention."

Denis Kasak (talk) 15:16, 25 November 2016 (UTC)

References

We draw on WP:MEDRS, not old papers like PMID 19597519 (very far from being MEDRS). With regard to adverse effects we should align with the Cochrane conclusion, rather than try to re-conclude in a different direction based on the evidence they considered. Alexbrn (talk) 15:21, 25 November 2016 (UTC)

PMID 19597519 is not a primary source, it is a meta-analysis. According to the resource you linked, meta-analyses are classified as secondary sources. In what way is the source not MEDRS? The article is also not that old. Though it is older than five years (a requirement which is not hard, according to the MEDRS guidelines), it examines different primary sources than other cited meta-analyses so it is not superseded by them.

Also, what about the other secondary source I mention that directly relates to weight loss and maintenance, and is not older than five years?

Regarding adverse effects, what I pasted is the conclusion. I pasted from both the authors' conclusion and the plain language summary.

Denis Kasak (talk) 15:32, 25 November 2016 (UTC)

It is more than five years old when we have a newer source (Cochrane), so is not really usable. You want to contradict a Cochrane systematic review with an older meta-analysis? Alexbrn (talk) 15:49, 25 November 2016 (UTC)

Contradict? No. I am trying to avoid overemphasizing a single review. Are you suggesting a Cochrane review defeats all other reviews, even when they are of similar age (such as this one), simply on the account of it being a Cochrane review? It should also be noted that with your latest edit, you are implying ramifications regarding weight maintenance in general, when the Cochrane review is specifically about overweight and obese people.

References

--Denis Kasak (talk) 16:10, 25 November 2016 (UTC)

In this instance the Cochrane systematic review is easily our best source. Alexbrn (talk) 16:16, 25 November 2016 (UTC)

Alexbrn, since you are simply reverting my edits under false pretenses, I am considering asking for a third opinion. There was no information loss; the only things deleted were unsupported attributions ("is commonly believed", WP:WEASEL), "no good evidence" (Why not just state plainly what the review concludes? You did previously say plain is better.) and the implication that the review talks about weight maintenance in general when it specifically looked at studies on overweight/obese people.

You also haven't responded to several of my points, specifically: 1) The source explicitly concludes that the mentioned adverse effects were not related to the intervention. 2) What is the reason for preferring only a single source among two similarly old secondary sources when one does not logically supersede the other? Insisting on a particular information which only adds coloured language but conveys the same information just makes this seem like an ulterior agenda.

I would like to ask one more time to discuss first instead of simply revert. Denis Kasak (talk) 17:45, 25 November 2016 (UTC)

To take the points in order

1. The Cochrane review says "Preparations of green tea are used as aids in weight loss and weight maintenance. Catechins and caffeine, both contained in green tea, are each believed to have a role in increasing energy metabolism, which may lead to weight loss". In other words, green tea is popularly used, and believed to be, a weight-loss aid. I'm open to re-wordings or our summary (though question the point), but this is information you deleted - it sets the scene nicely for this section.
2. "No good evidence" is a nice summary of the state of the evidence. We could go about it in a more long-winded way but the aim is to summarize in lay language.
3. You're not right about the adverse events. While Cochrane is equivocal about whether the AEs led to hospitalisation, there is no such equivocation over the milder AEs - so we now reflect that. The Cochrane review considers this aspect important enough for its conclusions, so we should too.
4. Cochrane is by far our best source. We should reflect it. Why would we want to do otherwise?
5. More generally, cut out the personalisation and WP:FOC. Maybe check by at WT:MED for a wider view, but this is an active article and I'm sure other editors will comment here if necessary. Alexbrn (talk) 18:22, 25 November 2016 (UTC)

@Alexbrn:, if you're going to remind others of WP:FOC, I'll remind you to adhere to the same. The idiom of the pot calling the kettle black comes to mind when I see such a remark. That's based on what seems like a pattern of a proneness to use unnecessarily inflammatory language in edit summaries when interacting with other Wikieditors (e.g., [10] "bad style", [11], [12] "silly", [13]). Everyone makes mistakes. I encourage you both to try to resolve your disagreement with community consensus and to refrain from using insulting or inflammatory language. TylerDurden8823 (talk) 20:15, 25 November 2016 (UTC)

"bad style" etc are comments focussed on content, of course. Alexbrn (talk) 20:18, 25 November 2016 (UTC)

1. The Cochrane summary is mainly talking about findings of previous studies which showed metabolic activity of various compounds in tea and serves as a motivation for the meta-analysis. The beginning of your sentence sounds primarily like it is setting the stage that the latter part of your sentence can contradict, yet the Cochrane review is narrower in scope (dealing mainly with studies with obese individuals) and cannot on its own serve to contradict the use of tea in weight loss in general. For this reason, it sounds weaselish and superfluous. Plainly stating that a review did not find a significant benefit for weight loss in obese individuals would be much more neutral and accurate. After all, the rest of the article is filled with plain claims such as "A review found [...]" and it is quite common on Wikipedia, so why is it a problem here?
2. Again, you are overstating what is claimed in the review. On a closer reading of the full review, several claims make this obvious. For instance, on page 23, the review discusses a subset of studies which attempted to intervene without caffeine and which found a statistically significant effect, stating the following: "Analysis of these ’caffeine-less’ studies showed small, statistically significant reductions in weight, BMI and waist circumference, indicating that the catechins in green tea and not caffeine were likely to be responsible for the modest effect on weight loss." Then, on page 24, in a section titled "Implications for practice", the following is stated: "Many of the trials included in this review had methodological deficiencies that should be taken into account when considering the results of this review." and "However, even though the changes may be small, any small loss combined with minimal adverse effects may have an overall positive impact on an individual attempting to lose weight." In light of this, the reduction of "small, but not statistically significant effects" to "no good evidence [for] ... any meaningful benefit" and seems even more wrong.
3. The plain language summary of the Cochrane article states "Most adverse effects, such as nausea, constipation, abdominal discomfort and increased blood pressure, were judged to be mild to moderate and to be unrelated to the green tea or control intervention." Furthermore, in the "Implications for practice" section, the review authors state "Adverse effects were minimal, with hypertension and constipation being most commonly reported.", clearly implying benignity, not risk, which makes the mention of risk in such a small section seem very out of place.
4. "Best" in what way? If there are multiple conflicting reviews and one does not obviously supersede the other (for instance, by taking into account new evidence), how is it decided which one is "best"? It seems obvious an unbiased report should take both sources into account.
5. I try very hard to avoid personalization, but it is very hard to focus on content when the points made are being ignored and misrepresented. You're right for reminding me, however, and I concede your point.

Denis Kasak (talk) 20:28, 25 November 2016 (UTC)

1. You present an ingenous reinterpretation of the source which is at odds with it. To quote the fuller background: "The promise of taking something 'natural' to help lose weight is appealing to consumers. For consumers who have tried many treatments, a natural alternative that they have not tried previously and one that is easily available offers new hope. Weight loss products made from natural sources, such as green tea, are being used by increasing numbers of overweight adults who hope that because the product is 'natural' it will be safer than prescription drugs and will be effective in helping them lose weight. " If anything we should be expanding on this consumber/SCAM aspect of green tea as a weight-loss aid.
2. We reflect what the Cochrane review concludes on effectiveness and (rare) AEs. We are not at liberty to dig around in the evidence considered to arrive at a different conclusion.
3. As above.
4. Cochrane is usually taken as the gold standard in EBM. We'd need a very strong source indeed to undermine it.
5. Sure - I think we're getting a better article despite what might appear to be a little local difficulty ;-) Alexbrn (talk) 20:45, 25 November 2016 (UTC)

1. I now understand better where you are coming from. I missed this position as green tea scams are not very widespread in my part of the world (so this may be a bit of a bias on both our parts). However, I respectfully disagree and maintain that Wikipedia should not specialize to become a consumer guide for scam prevention. The best way to counter scams is by informing about what is the case, not by oversimplifying to the point of misrepresentation.
2. It is not digging around to take a conclusion in context, by reading more than just the abstract of the article. In fact, WP:MEDRS recommends this in WP:NOABSTRACT, warning that "the abstract necessarily presents a stripped-down version of the conclusions and omits the background that can be crucial for understanding exactly what the source says.", which is exactly the case here. In any case, the second quote is from a subsection "Implications for practice" in a section titled "AUTHORS' CONCLUSIONS", so even if this objection was valid, it is not applicable.
3. As above. — Preceding unsigned comment added by Dkasak (talk • contribs) 11:37, 26 November 2016 (UTC)
4. It is not right to hide and/or cherry pick from conflicting, respectable contemporary sources, no matter how respectable, particularly in an area of fast-moving research. Even more so when the gold standard itself acknowledges a small positive effect and the possibility for its implications for practice, which is what created the conflict in the first place.
5. Fair enough.

Denis Kasak (talk) 21:15, 25 November 2016 (UTC)

What a negative page...

Why no single mention of, for example, the positive psychological effects of drinking tea? And for example theanine has been studied extensively for its relaxing and nootropic properties but it gets almost no mention at all. I feel like whoever wrote this page specifically wanted to make tea seem like a harmful beverage or at least with no health benefits at all. Cherry-picked all the studies that don't show any positive findings.

2001:14BB:40:72E9:59A6:61D:2DBF:A8EC (talk) 20:38, 16 April 2020 (UTC)

Any health claims need WP:MEDRS sourcing. What we have seems pretty good and so a fair representation of accepted knowledge on this topic. Tea's a nice drink but a medicine? ... nah. Alexbrn (talk) 06:26, 17 April 2020 (UTC)

Catechins and liver risks for green tea/green tea extract

I see it has been discussed on the talk page before, but I included a section on catechins and their association with idiosyncratic drug reactions which then cause drug induced liver injury. Green tea is included in livertox.gov and there are more papers that show this risk (moreso with the extract than the tea most likely). GTE is not solely in weight loss supplements and no matter where they are, they pose a risk to a small portion of the population. If people want more papers cited, I am happy to do a lit review. I am unfortunately very familiar with this as eight years ago, I almost died from exposure to green tea extract. I do not recommend liver failure, it's no fun. Most importantly, if you have had the reaction once, it should be treated like an anaphylaxis allergy, because it is known that with every exposure, the reaction will be worse.

Again, with GTE being added to so many products, it is important for people to be aware. I do not use or ingest anything that has green tea or GTE, because my initial liver failure was very severe, despite low exposure, and there are a shocking number of things that contain it, from foods, to gum, to candies, to mattresses to cosmetics. Sapphiremind (talk) —Preceding undated comment added 11:25, 26 July 2020 (UTC)