I love tea, especially black, and drink it pretty regularly–probably about 10 cups a week.
I have three reasons for doing so: taste, caffeine, and pretentious weenieness.
I don’t do it for health reasons. If I did, I’d feel obligated not only to drink tea when I didn’t really feel like it (“it’s good for me, so I ought to”), but also to do other healthy things, which I’ve been avoiding.
So, my question. Just how flimsy is the evidence out there that tea is good for you? And how especially flimsy is the evidence that black tea is good for you?
10 cups a week for a healthy adult is fine. Over consumption could be bad, this is not over consumption. 10 cups a day certainly could be.
Tea has some health benefits, Green tea scoring higher than black (same plant however). Antioxidants and all that.
*According to Mondal (2007, pp. 519–520):
Tea leaves contain more than 700 chemicals, among which the compounds closely related to human health are flavanoides, amino acids, vitamins (C, E and K), caffeine and polysaccharides. Moreover, tea drinking has recently proven to be associated with cell-mediated immune function of the human body. Tea plays an important role in improving beneficial intestinal microflora, as well as providing immunity against intestinal disorders and in protecting cell membranes from oxidative damage. Tea also prevents dental caries due to the presence of fluorine. The role of tea is well established in normalizing bloodpressure, lipid depressing activity, prevention of coronary heart diseases and diabetes by reducing the blood-glucose activity. Tea also possesses germicidal and germistatic activities against various gram-positive and gram negative human pathogenic bacteria. Both green and black tea infusions contain a number of antioxidants, mainly catechins that have anti-carcinogenic, anti-mutagenic and anti-tumor properties*.
Tea can inhibit iron absorbtion by the body, if you drink it within a few hours of a meal. So if you’re trying to keep your iron up, then don’t drink it with your iron-rich meals. If you’re trying to keep your iron down, then do drink it when you have an iron rich meal (I like beef too much to give it up entirely).
The concept that food can be “good for you” is a bit of a misconception. Most things we eat or drink contain some things we need or can use for normal metabolism. Essentially, FOOD is good for you. Otherwise, you starve to death. At the same time, some foods can be “bad for you,” (but not necessarily)particularly if they provide more of certain substances than you optimally need. For example, sugar is not bad for you or good for you, per se. We have to have a certain amount of sugar to provide energy for cells. So it’s good for you. If you took in NO sugar at all, you’d make some from the starch you eat, but that would be almost impossible, since virtually everything that contains starch contains some sugar. There is also such a thing as too much sugar - say for diabetics or people who are overweight, or for people who have a propensity toward tooth decay, for example. So it’s bad for you. But unless it’s poisonous, many things that are called bad for you are so-called because they contain more of some substance than most people need. For example, we make about 95% of the cholesterol in our blood. Taking in a small amount more is not a problem. Taking in a lot more *could *be a problem for some people. Not everyone. Salt is not good or bad for you - unless, for example, you happen to be the type of person whose high blood pressure is exacerbated by it. The term “good for you” or “bad for you” is essentially relative.
Is tea good for you? Bad for you? Unless you are dangerously short of certain nutrients, or unless you are dangerously over the safe limit of certain nutrients, the best way to answer the question is to think about it like this: Do you like it? Does it make you feel good to drink it? Does it make you feel bad? There ya go.
10 cups a week would be just about my bare minimum consumption I think. Mind you, I don’t take it with milk which has been shown to negate some of the health-promoting effects.
I prefer it with honey and lemon. Lovely stuff, and doesn’t stain the cups all brown either.
*Caffeine tolerance develops very quickly, especially among heavy coffee and energy drink consumers. Complete tolerance to sleep disruption effects of caffeine develops after consuming 400 mg of caffeine 3 times a day for 7 days. Complete tolerance to subjective effects of caffeine was observed to develop after consuming 300 mg 3 times per day for 18 days, and possibly even earlier.[68] In another experiment, complete tolerance of caffeine was observed when the subject consumed 750–1200 mg per day while incomplete tolerance to caffeine has been observed in those that consume more average doses of caffeine.[69]
Because adenosine, in part, serves to regulate blood pressure by causing vasodilation, the increased effects of adenosine due to caffeine withdrawal cause the blood vessels of the head to dilate, leading to an excess of blood in the head and causing a headache and nausea. Reduced catecholamine activity may cause feelings of fatigue and drowsiness. A reduction in serotonin levels when caffeine use is stopped can cause anxiety, irritability, inability to concentrate and diminished motivation to initiate or to complete daily tasks; in extreme cases it may cause mild depression. Together, these effects have come to be known as a “crash”.[70
Withdrawal symptoms—possibly including headache, irritability, an inability to concentrate, and stomach aches[71]—may appear within 12 to 24 hours after discontinuation of caffeine intake, peak at roughly 48 hours, and usually last from one to five days, representing the time required for the number of adenosine receptors in the brain to revert to “normal” levels, uninfluenced by caffeine consumption. Analgesics, such as aspirin, can relieve the pain symptoms, as can a small dose of caffeine.[72] Most effective is a combination of both an analgesic and a small amount of caffeine.
This is not the only case where caffeine increases the effectiveness of a drug. Caffeine makes pain relievers 40% more effective in relieving headaches and helps the body absorb headache medications more quickly, bringing faster relief.[73] For this reason, many over-the-counter headache drugs include caffeine in their formula. It is also used with ergotamine in the treatment of migraine and cluster headaches as well as to overcome the drowsiness caused by antihistamines.
[edit] Overuse
In large amounts, and especially over extended periods of time, caffeine can lead to a condition known as caffeinism.[74][75] Caffeinism usually combines caffeine dependency with a wide range of unpleasant physical and mental conditions including nervousness, irritability, anxiety, tremulousness, muscle twitching (hyperreflexia), insomnia, headaches, respiratory alkalosis[76] and heart palpitations.[77] Furthermore, because caffeine increases the production of stomach acid, high usage over time can lead to peptic ulcers, erosive esophagitis, and gastroesophageal reflux disease.[78]
There are four caffeine-induced psychiatric disorders recognized by the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition: caffeine intoxication, caffeine-induced anxiety disorder, caffeine-induced sleep disorder, and caffeine-related disorder not otherwise specified (NOS).
[edit] Caffeine intoxication
An acute overdose of caffeine, usually in excess of about 300 milligrams, dependent on body weight and level of caffeine tolerance, can result in a state of central nervous system over-stimulation called caffeine intoxication,[79] colloquially “caffeine jitters”. The symptoms of caffeine intoxication are not unlike overdoses of other stimulants. It may include restlessness, nervousness, excitement, insomnia, flushing of the face, increased urination, gastrointestinal disturbance, muscle twitching, a rambling flow of thought and speech, irritability, irregular or rapid heart beat, and psychomotor agitation.[77] In cases of much larger overdoses mania, depression, lapses in judgment, disorientation, disinhibition, delusions, hallucinations, psychosis, rhabdomyolysis, and death may occur.[80][81]*
10 cups of tea a day gets us to maybe 600mg. A healthy fit person could work up to that, but would have some minor associated problems- I’d certainly mention it during your regular physical. If you stopped suddenly youd be pretty miserable for a day.
I am not saying that healthy person could not consume well in excess of 10 cups a week, but that’s the example the OP gave us. I think 10 cups a day- especially large strong-brewed cops, is an amount where I’d consult my MD about it. It could be dangerous for a reasonable but small amount of dudes.
If you’re worried about insufficient iron uptake, putting lemon in your tea is a good idea.
I’m a slightly anemic tea addict. There’s a great write-up on tea and its effects on iron here.
Very valuable information at that link, thanks. I hadn’t realized that tea doesn’t affect heme iron absorbtion. So I guess there’s no point drinking tea specifically with beef, to reduce iron uptake (I’m actually trying to keep it low).
