Dear Nadine,
Does iced green tea have the same health benefits as freshly brewed green tea?
Sandra
Dear Sandra,
If you brew your green tea yourself and then ice it, it should have the same health benefits as freshly brewed hot green tea. But don't let the tea stand at room temperature for more than a few minutes before refrigerating it, as its catechin content can start to diminish.If your iced tea comes from bottled green tea, however, chances are you are getting far fewer catechins than you would if you drank freshly brewed green tea. The health-promoting catechins in green tea are sensitive to heat and oxygen, so they're easily destroyed during the processing, transporting and storing of bottled tea. Given that, it's not surprising that researchers at Oregon State University found that the polyphenols and antioxidant activity in some bottled tea products were 10 to 100 times lower than those found in brewed tea!
Dear Nadine,
I have been told that green tea is linked to kidney stones and possibly constipation. Is there any truth to this? I happen to drink a lot of it.
Thanks,Eve
Hi Eve,
Some people have trouble with stomach irritation or even diarrhea if they drink too much green tea, but I have never heard of any complaints about constipation. As for promoting kidney stones, green tea actually appears to do just the opposite. A study published in the Journal of Urology in 2005 found that green tea inhibited the formation of the most common kind of kidney stones (those made of calcium oxalate) in laboratory animals. The researchers believe that it interferes with the calcification process through its antioxidant effects.
Dear Nadine,
If a pot of freshly-brewed tea is left to stand from morning till night, what happens to the tea? Does it change chemically? If so, does it become more alkaline?
Greg
Dear Greg,
When tea is left to stand at room temperature, the health-promoting catechins begin to decrease. One study showed that the catechins decreased appreciably after the brewed tea was stored at 25 degrees Celsius (77 degrees Fahrenheit) for 36 hours. However, when it was refrigerated, (that is, stored at 4 degrees Celsius or 39 degrees Fahrenheit) for 36 hours, there were no changes in catechin levels. Green tea is alkaline, while black tea is on the low end of acidic. If anything, the tea would become more acidic overnight, since the catechins become oxidized and transformed into the theaflavins and thearubigens that are characteristic of black tea. In other words, the longer green tea sits out, the more it becomes like black tea. And that means it becomes less alkaline and more acidic.
Dear Nadine,
Can you tell me about the fluoride content of tea? I have used all types, the regular black/orange pekoe, green and white teas, and love them all.
Linda B.
Dear Linda,
Tea plants accumulate fluoride in their leaves over time, so the oldest leaves contain the most fluoride, while the youngest contain the least. Therefore, white tea (which is made from youngest leaves and buds) is your best bet if you’re super fluoride-conscious. Green tea that is made from older leaves, oolong tea and black tea has slightly more fluoride. The highest amount of fluoride is found in brick tea, a lower quality tea manufactured from the oldest tea leaves which is molded into the shape of a brick. Brick tea is the one to watch out for, as symptoms of fluorosis (permanent discoloration of the teeth) have been seen in Tibetan children and adults who drink large amounts of this kind of tea.
Dear Nadine:
My wife drank 2 cups of green tea and felt nausous. Yet she's had this tea before without getting these symptoms. Does green tea react with any medications?
D. Koz
Dear D:
In some people, green tea can contribute to heartburn, gastric irritation, nausea and reduction of appetite. If your wife has had the same kind of green tea (and, I’m assuming, the same amount) in the past without any symptoms, it seems likely that her nausea was caused by something else. Green tea does interact with some medications due to its caffeine content, but nausea is not typically a side effect of these interactions.
Dear Nadine,
How much caffeine is in a cup of green tea?
Jane
Jane,
An 8-oz. cup of green tea contains about 25-30 mg of caffeine. Black tea has about twice as much caffeine as green tea, weighing in at about 40 mg, while drip coffee has a nerve-jangling 100-120mg. Although some people who are caffeine-sensitive may find that drinking green tea (especially in large amounts) keeps them awake at night, most people don't have this problem. That may be because green tea also contains theanine, a natural tranquilizer that counteracts the stimulating effects of caffeine.
Dear Nadine,
Who first discovered tea?
Cindy
Dear Cindy,
Legend has it that tea was discovered some 5,000 years ago by the Chinese Emperor Shen-Nung, who was boiling water when some tea leaves blew through the window and settled into the pot. He drank the resulting brew and found it both comforting and delicious. In the Pen Ts'ao, a medical book that Shen-Nung wrote in 2737 B.C., he observed that tea "quenches thirst. It lessens the desire for sleep. It gladdens and cheers the heart." Tea drinking probably has its true origins in the rituals and practices of the early aboriginal tribes of Southeast Asia. As the tea bush grows wild in this area, the natives undoubtedly boiled the leaves in water to make a medicine -- and the practice of tea drinking has continued ever since.
Dear Nadine,
Does green tea really help you lose weight?
Thanks,
Ruth J.
Dear Ruth,
The results of some new studies are promising, indicating that green tea may be able to increase the body's rate of calorie burning, prevent excess weight gain and even reverse obesity. Although most tests have been preformed on laboratory animals, at least one study with humans showed that taking in the equivalent of 3 daily cups of green tea helped the body burn an additional 80 calories each day - without doing anything else!
Hi Nadine,
Besides green tea, I also drink rooibos tea, which originates in South Africa. I was wondering if you could compare the two. I know that both teas have health benefits and that rooibos tea doesn't contain caffeine.
Regards, Tasneem D.
Dear Tasneem:
Rooibos, which means "red bush," is a popular tea in South Africa used traditionally to treat fever, asthma, insomnia, colic in infants and skin disorders. Because it contains no caffeine, rooibos (also known as "red tea") can be given to babies and children and its low level of tannins helps prevent problems with iron absorption. Rooibos is not a member of the Camellia sinensis family, so it's considered an herbal tea, not a "true tea," and doesn't contain catechins. However rooibos is rich in polyphenols and has shown potent antioxidant and antimutagenic activities in "test tube" studies. These studies hint that rooibos might be helpful in preventing heart disease and liver injury and reducing cancer risk, and that it may also help fight the HIV virus. Still, the evidence is weak, and the lack of human studies make it impossible to make any medicinal claims for rooibos at this time. Green tea, a "true tea," is the major source of catechins, powerful disease fighters and potent antioxidants. Hundreds of scientific studies have found that green tea's catechins may help combat or prevent a variety of ailments ranging from heart disease to diabetes to cancer by protecting the body against free radical damage, boosting the immune system, regulating cholesterol levels, lowering high blood pressure, fighting the build-up of plaque in the arteries, interfering with the cancer process, fighting harmful bacteria and viruses, and assisting in weight loss.
Dear Nadine:
Has anyone ever eaten tea leaves? They are, after all, a vegetable!
Ely H.
Dear Ely:
Yes, tea leaves were considered a food long before they were ever used to create a beverage. In ancient times, the Siamese steamed tea leaves and ate them with pig fat, dried fish, oil, garlic and salt. The Burmese pickled their tea leaves and ate them as a salad. The Tibetans combined tea with goat’s milk butter, barley meal and salt, forming a thick paste that they ate for breakfast. I think we can all be glad that the world found a much more pleasant and palatable way to utilize the tea leaf!
Dear Nadine:
Does green tea contain estrogens?
Amy
Dear Amy:
No, there is no estrogen in green tea. In fact, there are numerous studies showing that green tea helps lower the levels of estrogen circulating in the blood, and may reduce a person’s risk of developing estrogen-dependent cancers such as breast and uterine cancer.
Dear Nadine:
Can you tell me the major benefits of drinking green tea? There is so much information in the news, but I wonder how much is really true.
Eileen G.
Decades of scientific research and thousands of laboratory, animal and human studies have found that green tea can help promote heart health, fight cancer, inhibit obesity, kill harmful bacteria and viruses, lessen free radical damage to the cells, and even slow the progression of age-related cognitive impairment and Alzheimer’s disease, among other things. No wonder it’s often referred to as “a steaming cup of medicine!"
Dear Nadine:
Does caffeine have any health benefits?
Alex M.
Dear Alex,
Caffeine affects the central nervous system, activating blood circulation, increasing mental alertness, counteracting sleepiness and helping you bounce back from fatigue. It improves athletic endurance by stimulating the breakdown and use of fat as an energy source, so the body doesn't deplete its glycogen stores. A natural diuretic, caffeine increases urination, which can help detoxify the body and lower the blood pressure. It's long been used as a remedy for hangovers because caffeine blocks absorption of alcohol and helps the body dispose of it at a faster rate.
Dear Nadine:
Does green tea interfere with the absorption of iron? When I tried to donate blood I was turned away because my iron was too low. They gave me a list of iron-rich foods, but also indicated that tea hinders the absorption of iron. I'm assuming they meant regular tea, not green tea. Thanks for your help,
Luanne
Hi Luanne,
Great question! It's black tea that interferes with the absorption of dietary iron and should be avoided by people who are iron deficient. However, green tea does appear to reduce absorption of the kind of iron found in plant foods (such as blackstrap molasses, whole grains, iron-fortified cereals and legumes). And, theoretically, green tea may reduce the absorption of iron supplements, although the effect isn't clinically significant in most people. To lessen the tea/iron interaction, you can try drinking your green tea between meals rather than with them. And avoid black tea entirely.
Dear Nadine:
I’ve been drinking green tea for about a week and have been surprised that it seems to have a calming effect on me. Just wondering if it really does have anti-stress properties or if it’s just my imagination.
Linda
Dear Linda,
The calming effect you've been experiencing after drinking green tea most likely comes from its theanine content. Theanine is an amino acid found primarily in green tea that has been shown to reduce mental and physical stress and promote feelings of relaxation. One human study found that after volunteers took 200 mg of theanine dissolved in water there was a significant increase in alpha wave activity in the brain, which is that "relaxed yet alert" state you seek in yoga class. So your new-found ability to relax is not just a figment of your imagination.
Dear Nadine:
I’ve read that green tea may be able to help clear up acne, but only if it’s decaffeinated. Is this true? Trammi T.
Dear Trammi,
I’m not aware of any studies that have found a relationship between drinking green tea and acne. But green tea does have antibacterial and anti-inflammatory properties, both of which should be of help with acne control.
As for whether or not you should drink decaffeinated green tea, many dermatologists advise limiting or excluding caffeine from the diet because it increases the release of stress hormones, which can make acne worse. Yet green tea is actually quite low in caffeine (only 25mg per 8 oz. cup, compared to 65 mg in black tea, and 185 mg in coffee). So you may want to try it and see how your skin reacts. If your complexion starts to look better, keep drinking! If not, try green tea that’s been decaffeinated using the carbon dioxide or "effervescent" method. (It should say so on the label.) You want tea that’s been decaffeinated this way since the standard method (involving ethyl acetate) destroys most of the catechins, which means that most of the health benefits are negated, as well.
Dear Nadine,
I read on the internet some time ago that the Japanese government conducted a survey of elderly people and found that those who drank 2 cups of green tea a day had much, much higher cognitive function than those who drank no green tea. Any truth to this?
Curtis P.
Dear Curtis,
The only somewhat similar study that I'm aware of is one published in the American Journal of Clinical Nutrition in 2006 involving 1,003 Japanese people age 70 or older. The researchers evaluated the volunteers’ cognitive function and measured the frequency of their green tea consumption. They concluded that drinking higher amounts of green tea was associated with a lower incidence of cognitive impairment.
Specifically, drinking 4-6 cups of green tea per week or 1 cup per day lowered the incidence of cognitive impairment by 38%. And drinking 2 or more cups of green tea per day lowered the incidence of cognitive impairment by 54%. It certainly sounds like an easy (and tasty) way to cut your risk of cognitive impairment in half!
Dear Nadine,
How is green tea extract made? Is it safe to take it?
Bethany
Dear Bethany,
To make green tea extract, the catechins (most often EGCg) are isolated and drawn out of the tea leaf using water or steam, then condensed before spray drying. The resulting powder can be put into tablet or capsule form or made into a liquid. Green tea extract may contain many times more catechins than could be found in a cup of green tea. However using green tea extract may be risky: there have been some reports of liver damage after taking the extract in large amounts.
Hi Nadine,
I’ve been reading a book in which the author says that it’s important to avoid things like alcohol, carbonated drinks, coffee and tea in order to maintain the proper ph balance in our blood. I have been enjoying a couple of cups of green tea per day for a while now and am concerned about the added acidity. Should I be concerned, or is this level of intake too small to be significant?
Darrell
Dear Darrell,
Green tea is actually alkaline, while black tea is on the low end of acidic. However, if green tea is exposed to oxygen (either before or after brewing), it becomes more like black tea, and therefore more acidic. You can tell if green tea has become oxidized just by looking at its color. If it's greenish, the catechins are present. If it's brownish, the catechins have been transformed into the compounds that give black tea its characteristic flavor and color, making it more acidic.
But none of this really matters much as the alkaline/acid levels of green tea are so close to neutral they shouldn’t interfere with the maintenance of the pH balance of the blood.
Dear Nadine,
My husband is a diabetic and on medication. Is green tea okay for him to drink?
Patricia
Dear Patricia:
In general, green tea appears to be helpful for diabetics. One human study found that green tea reduces the risk of developing Type II diabetes, while animal studies have shown that it lowers blood sugar, enhances glucose tolerance and protects against damage to insulin-producing cells. It may even be able to improve the release of insulin from the beta cells of the pancreas!
But for those taking medication for their diabetes, drinking green tea (especially a lot of it) may not be a good idea. That's because the caffeine in green tea can make blood sugar control more difficult in some people. This shouldn't be a problem if the green tea is decaffeinated. However, be sure to buy green tea that's been decaffeinated through the effervescent or carbon dioxide process, which perserves the catechins. And, as always, consult your physician before drinking green tea, especially when taking any medications.
Dear Nadine,
I've heard that there is aluminum in green tea. Is this dangerous?
Deanna
Dear Deanna,
Like potatoes, spinach and foods processed with aluminum additives, tea plants contain greater amounts of aluminum than most other foods. However, most experts believe that our exposure to the levels of aluminum naturally present in our food, water and aluminum pots and pans is generally not harmful. Medications like antacids or buffered aspirin, however, are a much larger (and more worrisome) source of aluminum. While the daily intake of aluminum from food is estimated to be about 5-20mg., it can be as high as 5 grams if you take aluminum-containing medications on a daily basis!
But if you're still concerned about the aluminum content of your tea, be aware that it's significantly higher in brick tea, a lower quality tea manufactured from the oldest tea leaves, which is molded into the shape of a brick. To limit your aluminum intake, avoid brick tea and consider making your tea with non-flouridated water. That's because when aluminum is combined with flouride, it forms a compound that is absorbed by the body. (Aluminum itself is not readily absorbed by the body.) Since tea is already a natural source of fluoride (especially brick tea), brewing it with fluoridated water may serve to increase aluminum's absorbability.
Finally, remember that moderation is the key. Most likely, drinking a couple of cups of green tea every day won't increase your aluminum intake too drastically. However, if you consistently drink 10 daily cups of brick tea, it could be another story!
By the way, Salada teas are imported and blended in the United States. The tea is carefully purchased from select tea gardens all over the world and "brick tea" would NOT be considered as a suitable component to the great Salada blends.
Chris Recchia, Manager of Quality and Innovation
Salada Tea
I've heard that green tea help ease arthritis and joint pain. How does that work?
Jason
Green tea appers to ease joint pain through its anti - inflammatory properites. In a 2007 study, cells were taken from the joints of people with rhumeatiod arthritis and then inflammed. Then green tea extract was added. The green tea extract blocked a chemical chain reaction that promotes inflammation and leads to joint damage. So in effect, the green tea extract broke the inflammation chain.
My husband has pneumia. Is it a good idea to give him green tea?
Elyse
Green tea has its own antibacterial and antiviral capabilities, put there by Mother Nature to defend against invading insects, bacteria, fungi, and viruses. And its effects against invading pathogens are surprisingly powerful! Studies have shown that green tea catechins can fight or even destroy the bacteria that cause pneumonia, cholera, abcessess, botulism, dysentery, and food posioning, not to mention those that cause cavities and bad breathe. As for viruses, the catechins can inhibit the action of the flu virus, herpes simplex, polio, and HIV, just to name a few.
Just by drinking green tea, your husband may be able to "borrow" some of the incredible disease-fighting prowess of the tea leaf - and it doesn't take a gallon of tea to do this! One study found that the amount of catechins in just one cup of tea was 2-3 times greater that needed to kill the kind of bacteria that cause cholera. However, as always, before drinking green tea be sure that you husband consults with his physician.
Is it true that green tea thins the blood?
Emma
Yes, green tea has blood thinning characteristics. It inhibits platelet aggregation and the formation of clots, reducing blood coagulation and platelet clumping, and may even help break down clots that already formed. One way that it works is by inhibiting the action of thromboxane, the substance responsible for both clot formation and blood vessel constriction. Because of this many doctors recommend that you limit your green tea intake if you're taking blood thinning medications, as it may increase the risk of bleeding or bruising. However this only seems to be a problem when green tea is taken in large amounts, say 1/2 to one gallon per day.