wmartin@brl-tgr.ARPA (Will Martin ) (11/20/85)
In the discussions of quitting smoking, and regarding addictive substances, people have often mentioned coffee. No one talking about this area ever seems to mention tea. Tea contains caffeine, of course, and I thought that it was this addictive substance that was being avoided by cutting out coffee. I'd like to see some discussion about tea. As a bit of personal history, I've never liked and so never drank coffee. I do like tea, and drink quite a bit of iced tea all year round, and some hot tea at times during the winter. However, I have gone for periods of some days up through some weeks without drinking any tea, and never noticed withdrawal symptoms (that I could define as such). I have heard that there are substances in tea that inhibit the body's ability to absorb or use vitamin C, so I avoid taking my usually-daily ration of vitamin pills, which includes a gram of C, within some hours of drinking tea. (I normally take the pills after lunch, and drink tea only in the evening.) I also notice no insomniac effect from tea, often drinking a glass while reading in bed before falling asleep. (I normally drink Tender Leaf for iced tea, and all sorts of various gift and bulk teas for hot tea. I drink tea straight, no sweetening, sometimes with lemon.) So, several questions: 1) Does ordinary American tea-bag tea contain so little caffeine that it doesn't have much effect? 2) Does iced tea impart much less caffeine to the body than hot tea will? (Assume the same brand tea, just temperature difference.) 3) Is there any truth to the idea of tea affecting vitamin potency or absorbtion? Which vitamins? What about affecting other food substances? Any other tea-related coments would be welcomed. Regards, Will Martin UUCP/USENET: seismo!brl-bmd!wmartin or ARPA/MILNET: wmartin@almsa-1.ARPA
sdyer@bbncc5.UUCP (Steve Dyer) (11/22/85)
> 1) Does ordinary American tea-bag tea contain so little caffeine that it > doesn't have much effect? I bought a rather fascinating book last week called, not surprisingly, "Caffeine", edited by Peter Dews, one of the first behavioral pharmacologists. One of the monographs in this collection defines the "standard caffeine content value" of tea as 40mg/5 oz. cup for fresh-brewed leaf or bag tea, and 30 mg/5 oz. cup for instant tea. This single value naturally can't accomodate the measured variability of tea's caffeine content in studies--it's best to think of it as a modal value. The actual values range from 30-48mg, 28-44mg and 8-91mg in three different studies. Compare these with the standard values for coffee: brewed, 85 mg./5oz., instant, 60 mg/5oz, and decaffeinated, 3 mg/5oz. So, roughly, tea contains half the caffeine of coffee. > 2) Does iced tea impart much less caffeine to the body than hot tea will? > (Assume the same brand tea, just temperature difference.) Note that instant tea contains 25% less caffeine than brewed tea. If your iced tea is made using instant tea, this might help explain your experience. Tea is usually brewed using boiling water, and then either served hot or cold. One would expect identically prepared teas to contain the same amounts of "biologically available" caffeine, regardless of their serving temperatures. I don't know about trying to brew tea using cooler water. > 3) Is there any truth to the idea of tea affecting vitamin potency or > absorbtion? Which vitamins? What about affecting other food substances? Teas contain tannins. I've heard anecdotally that they can cause constipation when consumed to excess (and we know from earlier articles how dangerous THAT is :-)). I know nothing about tea and vitamins. -- /Steve Dyer {harvard,seismo}!bbnccv!bbncc5!sdyer sdyer@bbncc5.ARPA
jcp@osiris.UUCP (Jody Patilla) (11/22/85)
> In the discussions of quitting smoking, and regarding addictive > substances, people have often mentioned coffee. No one talking about this > area ever seems to mention tea. Tea contains caffeine, of course, and I > thought that it was this addictive substance that was being avoided by > cutting out coffee. I'd like to see some discussion about tea. > A cup of tea contains about a third as much caffeine as the same amount of coffee. The other main substance in tea is tannic acid - the stronger you make the tea, the more tannin it contains (which is why it gets bitter). At a certain point, the increased tannin actually causes a decrease in the amount of caffeine. Both tannin and caffeine have a destructive effect on vitamins, so you should not take the two together - better to have the tea 20 minutes before or after when you take the vitamins. I just recently read that a person would have to drink more than 10 cups of tea a day to take in enough caffeine to be a problem. Cheap teas, by the way , (like Liptons, red Rose, etc) contain more tannin than better quality teas. SOme people feel that excessive tannic acid intake over time can cause irritations of the esophagous and stomach linings, and possibly cancer but I haven't seen proof of this. A friend once told me that the British have a much lower rate of throat cancer than the Chinese because the Brits put milk in their tea, but I haven't quit drinking my tea plain yet. -- jcpatilla Mountain View is paid a diplomatic visit by giant Lunar reptiles that want our hot tubs but can't find any so they leave.
swb@lasspvax.UUCP (Scott Brim) (11/24/85)
To me, the caffeine in tea is not nearly so significant as the tannins
(this is in "bush" teas and bark teas - not herbal teas). There is a
clear correlation between drinking bush tea and cancer of the
esophagus. It's probably the tannins. The only way to get away with
drinking a lot of tannin-containing tea is to put milk in it. The
natural function of tannins is to bind with protein, and the milk
proteins bind with the tannins and make them [much more??] harmless.
--
Scott Brim 607-256-8686
Arpanet: swb@devvax.tn.cornell.edu
Usenet: {decvax, ihnp4, cmcl2, vax135}!cornell!swb
Bitnet: swb@cornellawilde@apollo.uucp (Scott Wilde) (11/26/85)
I remember reading something about a year ago that said that drinking hot
tea increased your risk of cancer ( of the esophagus, I believe). The
article also said that adding milk or cream to the tea eliminated (reduced?)
this problem by binding to the tannin in the tea. Perhaps someone else
knows more about this.
(this isn't really surprising, since everything else causes cancer too :-))
--
Scott Wilde
...decvax!wanginst!apollo!wilderon@brl-sem.ARPA (Ron Natalie <ron>) (11/27/85)
> The only way to get away with > drinking a lot of tannin-containing tea is to put milk in it. The > natural function of tannins is to bind with protein, and the milk > proteins bind with the tannins and make them [much more??] harmless. Real useful. I've discovered (by accident in England where they insist on putting milk in their tea) that nothing destroys the flavor of tea more than puting milk in the tea. -Ron
sdyer@bbncc5.UUCP (Steve Dyer) (11/27/85)
> There is a > clear correlation between drinking bush tea and cancer of the > esophagus. It's probably the tannins. Sigh, references, please. Whatever the risk, it must be very small, for I have never seen any such a claim in the admittedly conventional literature that I habitually read. I am open to being convinced otherwise. Convince me, please. -- /Steve Dyer {harvard,seismo}!bbnccv!bbncc5!sdyer sdyer@bbncc5.ARPA
raghu@rlgvax.UUCP (Raghu Raghunathan) (11/27/85)
> > The only way to get away with > > drinking a lot of tannin-containing tea is to put milk in it. The > > natural function of tannins is to bind with protein, and the milk > > proteins bind with the tannins and make them [much more??] harmless. > > Real useful. I've discovered (by accident in England where they insist > on putting milk in their tea) that nothing destroys the flavor of tea > more than puting milk in the tea. > -Ron Not true at all! I know nothing about the caffein and tannin contents of tea; but can categorically state that a fair amount of milk and sugar are absolutely essential to bring out the full flavour of tea. The English know how to drink their tea; they probably learned it from the Indians! - Raghu.
john@ur-tut.UUCP (John Gurian) (12/03/85)
> > There is a > > clear correlation between drinking bush tea and cancer of the > > esophagus. It's probably the tannins. > > Sigh, references, please. Whatever the risk, it must be very small, > for I have never seen any such a claim in the admittedly conventional > literature that I habitually read. I am open to being convinced otherwise. > Convince me, please. There is not, to my knowledge, a clear correlation between tea and cancer of the esophagus. What there IS, rather, is a theory that drinking hot tea (or any other hot liquid, for that matter) may be a risk factor for esophageal cancer. It has been shown that drinking hot tea (liquids) can raise the intraesophageal temperature to dangerous levels, epithelially speaking. Damage to the epithelium would lead to increased cell division in the basal layer to make up for the cells being sloughed off; this is a good environment for a neoplasia to take root (that is, the high rates of cellular division & reproduction). I believe that this rationalization was reached after empirical observations that that some groups that drink lots of tea & coffee have higher than average incidences of esophageal cancer, which is not a common affliction to begin with. However, a study was done comparing two cultures (in Iran, of all places), one of whom had a high esoph CA incidence, the other a low incidence. Their diets were quite different, but both diets contained tea. This would tend to disprove an otherwise logical theory, although the study was not done with this question in mind. At any rate, there is still no clear etiology for esophageal cancer. REFERENCE: Robbins/Cotran/Kumar : Textbook of Pathology, 3rd Edition (Big Red) As ever, John Gurian University of Rochester School of Medicine seismo!rochester!ur-tut!john
hankb@teklds.UUCP (Hank Buurman) (12/06/85)
In article <3441@brl-tgr.ARPA> wmartin@brl-tgr.ARPA (Will Martin ) writes: >3) Is there any truth to the idea of tea affecting vitamin potency or >absorbtion? Which vitamins? What about affecting other food substances? Coffee and tea are diuretics (they make you piss) and vitamin C is a water soluable vitamin. Need I say more? (-: The B vitamins are also water soluable. -- Hank Buurman Tektronix Inc. ihnp4!tektronix!dadlac!hankb ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ "Firey, the angels fell. Deep thunder rolled 'round the shores, burning with the fires of Orc." -- Roy Baty, Nexus 6, Combat Model, N6MAA10816 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
sdyer@bbncc5.UUCP (Steve Dyer) (12/08/85)
> >3) Is there any truth to the idea of tea affecting vitamin potency or > >absorbtion? Which vitamins? What about affecting other food substances? > Coffee and tea are diuretics (they make you piss) and vitamin C is a > water soluable vitamin. Need I say more? (-: > > The B vitamins are also water soluable. Sorry, but this argument doesn't "hold water". (Yikes, a thousand lashes with a wet noodle for that one!) Diuretics haven't been shown to increase the need for water-soluble vitamins, and mild diuretics such as the caffeine or theobromine in tea and coffee certainly would not be expected to contribute to this. This is probably because the excretion of ions by the kidney into the urine is an active process which doesn't contribute greatly to the excretion of vitamins unless there is a surfeit (as would occur in high dosagepr.) You might as well argue that it's a bad idea to drink lots of water. -- /Steve Dyer {harvard,seismo}!bbnccv!bbncc5!sdyer sdyer@bbncc5.ARPA
ems@amdahl.UUCP (ems) (12/10/85)
> > There is a > > clear correlation between drinking bush tea and cancer of the > > esophagus. It's probably the tannins. > > Sigh, references, please. Whatever the risk, it must be very small, > for I have never seen any such a claim in the admittedly conventional > literature that I habitually read. I am open to being convinced otherwise. > Convince me, please. Sigh, another condecending request for references. The purpose seems to always be the same. To equate a lack of references with a lack of truth. While references are fine for academic works, and would even be nice for the net, they are not the be-all and end-all of information. I, too, remember reading *somewhere* of *some* study which showed a correlation of tannins with esophageal cancer. Milk was found to inhibit it. My references? My own memory of an article in *some* magazine. If you want references, go look them up in the library. The net is not a library nor is it an acdemic convention where finished papers are being presented. It is more like a cocktail party. What would you think of the average person who kept berating people for not having references at an *informal* party? (Please forgive and typos, and other misc. faults in the use of the language. Consider this to be a sample of coloquial use rather than literary use of the language... I hope also to be be forgiven for complaining about another persons opinion. It is just that the constant harping on references is getting very old and very boring...) -- E. Michael Smith ...!{hplabs,ihnp4,amd,nsc}!amdahl!ems This is the obligatory disclaimer of everything.
sdyer@bbncc5.UUCP (Steve Dyer) (12/10/85)
> > Sigh, references, please. Whatever the risk, it must be very small, > > for I have never seen any such a claim in the admittedly conventional > > literature that I habitually read. I am open to being convinced otherwise. > > Convince me, please. > > Sigh, another condecending request for references. The purpose seems > to always be the same. To equate a lack of references with a lack > of truth. While references are fine for academic works, and > would even be nice for the net, they are not the be-all and end-all > of information. I, too, remember reading *somewhere* of *some* > study which showed a correlation of tannins with esophageal cancer. > Milk was found to inhibit it. My references? My own memory of > an article in *some* magazine. If you want references, go look > them up in the library. The net is not a library nor is it > an acdemic convention where finished papers are being presented. > It is more like a cocktail party. What would you think of the > average person who kept berating people for not having references > at an *informal* party? > > [blather...] Sorry, but this is a moronic comment by any standard. FYI, this isn't net.politics, it's net.med, and to do my own harping once again, medicine is ultimately based on the application of the scientific method, and therefore it is only reasonable to ask for extraordinary claims to be backed up by some semblance of factual research. Have you ever noticed that the people who complain about such an approach are the ones who take an intellectually lazy approach toward evidence, and are usually the ones saying completely outrageous things? When I hear something being passed off as fact which isn't consistent with my own knowledge, I ask for references so I can better judge its reliability. But far from being an insult or attack, as E. Michael would prefer to see it, it's actually a gesture of respect, since it means that I am interested enough in the claim that I would bother with it at all. I am happy to give references if someone asks me, and I am also happy to hear the reply "I, too, remember reading *somewhere* of *some* study...", since that puts the comment in its proper place. To get back to particulars, there is nothing wrong with saying "I read somewhere that..." No one is his right mind would reply with "references please", since it's clear that this is anecdotal evidence. No one is saying anything about truth/falsehood, mind you, although you have to keep reminding the E. Michael's of this world of this fact again and again. But the original poster about tea, tannins and esophageal cancer made a very clear, unambiguous statement as if it was established fact. Here is the original: > > > There is a > > > clear correlation between drinking bush tea and cancer of the > > > esophagus. It's probably the tannins. Given that this "fact" isn't widely held, are we suddenly being "condescending" in asking for references? What's the point of this group, anyway, a rumor mill? I like to think that we always TRY to approach truth here, and we won't get anywhere near that goal if a statement like the one above isn't checked for reliability. -- /Steve Dyer {harvard,seismo}!bbnccv!bbncc5!sdyer sdyer@bbncc5.ARPA
hankb@teklds.UUCP (Hank Buurman) (12/12/85)
In article <307@bbncc5.UUCP> sdyer@bbncc5.UUCP (Steve Dyer) writes: >> >3) Is there any truth to the idea of tea affecting vitamin potency or >> >absorbtion? Which vitamins? What about affecting other food substances? >> Coffee and tea are diuretics (they make you piss) and vitamin C is a >> water soluable vitamin. Need I say more? (-: >> >> The B vitamins are also water soluable. > >Sorry, but this argument doesn't "hold water". (Yikes, a thousand >lashes with a wet noodle for that one!) Diuretics haven't been shown to >increase the need for water-soluble vitamins, and mild diuretics such >as the caffeine or theobromine in tea and coffee certainly would not >be expected to contribute to this. This is probably because the >excretion of ions by the kidney into the urine is an active process >which doesn't contribute greatly to the excretion of vitamins unless >there is a surfeit (as would occur in high dosagepr.) You might as >well argue that it's a bad idea to drink lots of water. Sorry I didn't make myself clear Steve. The point I was making was; these vitamins are water soluable, therefore the more H2O you excrete, the more vitamins B&C you excrete. Liquids with a mild diuretic will slightly increase this rate of excretion. However, the rate increases sharply if you are a heavy coffee or tea drinker, simply because you have to pee more and therefore deplete your bodys' stores of B&C sooner. -- Hank Buurman Tektronix Inc. ihnp4!tektronix!dadlac!hankb ======================================================================= "Any sufficiently advanced technology is indistinguishable from magic." =======================================================================
friesen@psivax.UUCP (Stanley Friesen) (12/13/85)
In article <2359@amdahl.UUCP> ems@amdahl.UUCP (ems) writes: >> >> Sigh, references, please. Whatever the risk, it must be very small, >> for I have never seen any such a claim in the admittedly conventional >> literature that I habitually read. I am open to being convinced otherwise. >> Convince me, please. > >Sigh, another condecending request for references. The purpose seems >to always be the same. To equate a lack of references with a lack >of truth. I would not say it was condecending. Nor do I equate lack of references with lack of truth - only with lack of *verifiability*. Without proper documentation I cannot properly evaluate any claims made. So I cannot make *any* judgement about the truth or falsity of the statements. In the absence of evaluable evidence I simply take the easiest course and retain my current opinions. So yes, convince me please! Give me usable evidence and I will at least consider it to see what its significance is. > While references are fine for academic works, and >would even be nice for the net, they are not the be-all and end-all >of information. I, too, remember reading *somewhere* of *some* >study which showed a correlation of tannins with esophageal cancer. >Milk was found to inhibit it. My references? My own memory of >an article in *some* magazine. In that case say so, do not present it as a *fact*, but rather as an idea you once heard. > If you want references, go look >them up in the library. The net is not a library nor is it >an acdemic convention where finished papers are being presented. >It is more like a cocktail party. Well, I think the *discussion* groups might be called a cocktail party, but this is *supposed* to be a technical information group, if I am going to be using the info I get I need to have *some* idea of its reliability. > -- Sarima (Stanley Friesen) UUCP: {ttidca|ihnp4|sdcrdcf|quad1|nrcvax|bellcore|logico}!psivax!friesen ARPA: ttidca!psivax!friesen@rand-unix.arpa