Skip to comments.Uncovering the secrets of tea
Posted on 11/16/2012 12:17:17 AM PST by neverdem
Everyone knows that a cup of tea is good for you, but the exact reasons for this are not clear. To discover the fundamentals of teas health benefits, scientists in Germany have investigated the interactions of compounds from tea with cells on a molecular level.
Both green and black tea contain around 30,000 polyphenolic compounds, some of which have been shown to have numerous health benefits, including reducing cardiovascular disease, osteoporosis and inflammation. Despite their positive effects, which have been seen in epidemiological findings and clinical trials, their exact biochemical mechanism is still not clear. Polyphenols can act as antioxidants, and for a long time this was thought to be the reason for their health benefits. However, recent studies have shown that this only plays a small part in their effectiveness.
To uncover how tea polyphenols affect cells, Nikolai Kuhnert from Jacobs University Bremen, and colleagues, set out to investigate the interactions of tea polyphenols at a molecular level. Working from a previous report that showed that tea polyphenols accumulated in the nuclei of plant cells, they used mass spectrometry and circular dichroism spectroscopy to measure the interactions between individual polyphenol molecules and biomolecules from the nucleus histone proteins, double-stranded DNA and quadruplex DNA.
Flavanols from tea accumulate in the cell nucleus, which could help in understanding their beneficial health effects © Shutterstock
The scientists found that the polyphenols bound to the proteins and the DNA, but also that two major polyphenols showed selectivity for binding to quadruplex DNA over double-stranded DNA. Quadruplex DNA makes up the telomeres at the ends of chromosomes, which protect the chromosome from deterioration (for example, through ageing). One can speculate that any compound able to bind to the quadruplex stabilises it and prolongs the life-span of an organism, says Kuhnert. Additionally, the telomere plays an important role in cancer therapy.
Susanne Henning from the Centre for Human Nutrition, University of California Los Angeles, US, comments: It appears to be highly sophisticated chemistry. However, as the authors point out, this is only an in vitro study. There are limiting factors for the tea polyphenols being taken up and highly metabolised and excreted rapidly in the urine. Kuhnert agrees: For this work, it needs to be urgently established whether any phenolics accumulate in the cell nucleus of human cells under dietary settings.
The team hopes that this work will spark new avenues of research in tea polyphenols and are planning to continue their work on the characterisation of processed foods, identifying compounds with interesting biological activities. They are particularly interested in black tea, caramel and roasted coffee, and are just beginning to investigate cocoa, which is even more complex than tea.
G Mikutis et al, Food Funct., 2012, DOI: 10.1039/c2fo30159h
Be careful though, black tea is high in oxalates. Too much of a good thing can be a bad thing. Kidney stones are no fun.
Now they say oxalates in diet likely don’t affect kidney stones and if anything, tea may help keep them away:
Coffee is good for you too a couple cups a day.
Three years ago...I tossed away the sodas and stuck to unsweetened tea. In an average month...I might drink ten ounces of a soda...that’s it. I admit....I drink probably half-a-gallon of tea per day....but I think it’s a better substitute than soda.
Coffee, OTOH, is a different story. Unfortunately, I need to go decaf, so I suspect I lose much of the benefits of coffee as well.
Not at all. You take the tea. You dump it in the harbor. Easy! ~ Sirius Lee, Tea Party
Years ago I started drinking iced tea instead of soda. I was drinking about two quarts a day. Within a year I had an humongous stone. I now drink one to two cups a day and after a recent surgery the xray revealed no more stones. I was also eating a salad every day with spinach which is also high in oxalates. Not any more.
My urologist told me what he believes about oxalates and after my experience I believe what is said about them.
A single article that raises doubt based on no scientific evidence is not enough to get me thinking otherwise.
There are lots of ins and outs to teas. A big unknown is the effect of processing and oxidation on tea’s medicinal values.
One tea not mentioned is fairly new to US markets, as such, called “white tea”, it is processed differently from green and black tea, with the intent to minimize oxidation.
As far as some people getting problems with stones from drinking too much tea, there is likely a genetic component as well. There are at least three major ways stones form, and tea would likely affect only one of them.
The Chinese are currently very strong advocates of strong and frequent tea enemas as a means of fighting colon cancer.
This is why we have sugar! I was never a coffee or tea drinker until I started having joint pains. Amazing how tea eliminated them.
Even WITH sugar, I'm afraid. Sweet iced tea is one of the staple summer drinks in the South. Never could stand it.
I’ve been a green-tea drinker for many years, and, I have to admit, I have no other explanation for the increasing health I have noticed. Since I haven’t done much else or made many changes in my diet, I am hopefully choosing to credit the properties of the green tea. I drink about 6 cups a day, as my primary hydration, so it’s not a “1-cup-and-done” situation.
Try a good fresh quality tea. I personally like Stash Earl Grey strong as I can make it with no milk or sugar. I never liked tea until I had my first cup of loose lief Darjeeling but to each is own. I don’t like it sweetened, if you’ve never tried it plain maybe that would make a difference.
Years ago, probably in the’80’s, reading some health report, I read that a serious study had concluded that two cups a day of tea (any kind) was very beneficial in keeping strong bones.
The study said two cups of tea a day was the thing...not one and not more. (Sorry, I don’t have a link.)
If true, this is important, and I wonder if there were follow up studies.
Try HONEY in your drinks!
Black and especially green tea is full of toxic fluoride. Look it up.
White tea is supposed to be better.
Without these who cares about a long life?