and has a hostof health benefits relating to dental health, blood sugar levels, cholesterol, and weight loss. But researchers have found, whilst examining the active constituent of green tea, the epigallocatechins, or EGCG for short, that it may affect the way the body uses folate. Folate is important for pregnant women as it prevents neural tube birth defects in babies. The good news on caffeine drank during pregnancy, from coffee and tea, is that a moderate amount is fine. Two studies, one by Danish scientists who interviewed more than 88,000 pregnant women, and the other by the Yale University School of Medicine, had similar findings on caffeine during pregnancy.

As with most negative side effects attributed to green tea their are balancing positive effects. According to one study, drinking one or more cups of tea can almost halve the risk of heart attack (Sesso et al. 1999). Green tea contains a much higher concentration of theanine than other teas. Theanine has been proven to lower blood pressure (Abe et al. 1995; Yokogoshi et al. 1995; Yokogoshi et al. 1998a). It works through its GABA enhancing effects. Along with its calming effect on the brain, GABA also lowers blood pressure.

quarters of kidney stones are composed of calcium combined with phosphate or oxalic acid.Tea is a concern because it is rich in oxalic acid. To put it in perspective, there are other foods rich in oxalic acids, such as beet greens, chocolate, rhubarb, spinach, and sorrel. If you do eat these foods, avoid paring them with another food high in calcium, such as spinach and cheese or chocolate and milk. A 1998 American study published in the April edition of the Annals of Internal Medicine found that drinking tea reduces kidney stones risk in women. Green tea contains catechins. They act as powerful antioxidants, wiping out free radicals that can form urinary stones. A 2005 study conducted by Nagoya City University Graduate School of Medical Sciences found that laboratory rats drinking green tea were less likely to develop stones in the urinary tract. This study was confirmed by a separate 2006 study conducted by Seoul National University. In both green tea and kidney stones studies, the scientists believed that green tea antioxidants inhibit the formation of urinary stones. The probability of tea causing kidney stones can be dramatically reduced by ingesting some form of calcium along with the tea in order to form the calcium oxalate in the digestive tract (where it cannot be absorbed and will pass through), rather than in the bloodstream or the kidney.

If you have Kidney Disease avoid drinking teas with too much caffeine, such as darjeeling, assam and other types of black tea. White and green tea are typically lower in caffeine and also have corresponding beneficial effects. You don't need to put any sugar in these types of teas because they are not very astringent.

Japan have discovered that theanine is a caffeine antagonist, meaning that it offsets the "hyper" effect of caffeine (Kakuda et al. 2000). That is why many people will have a "soothing" cup of tea and not a soothing cup of coffee. Theanine does not cause drowsiness like kava kava, nor does it interfere with the ability to think clearly like prescription tranquilizers.There is evidence that tea exerts far more than just a psychological effect. According to one study, drinking one or more cups of tea can almost halve the risk of heart attack (Sesso et al. 1999). Green tea contains a much higher concentration of theanine than other teas. Theanine has been proven to lower blood pressure (Abe et al. 1995; Yokogoshi et al. 1995; Yokogoshi et al. 1998a). It works through its GABA enhancing effects. Along with its calming effect on the brain, GABA also lowers blood pressure.

1.8 mg of fluoride. Among populations habitually consuming black tea, water fluoridation is not only unnecessary but also possibly harmful...The target organs of chronic fluoride intoxication are not only the teeth and skeleton, but also the liver, kidney, nervous and reproductive systems. A March 2008 tea and fluoride study published in Food and Chemical Toxicology found up to 4.5, 1.8, and 0.5 mg/L fluoride in black, green and white teas, respectively, when brewed for 5 minutes. 61 teas were included in the sample. According to 1997 ADA data, 3 and 4 milligrams daily are adequate for women and men, respectively, to prevent fluoride's adverse effects. It is much lower for children. In 2006, the National Research Council reported the basis for those levels should be reduced. Fluoride content is measured in parts per million (ppm). 1 ppm is equivalent to 1 milligram of fluoride in 1 litre of water. In the United States, drinking water can contain up to a maximum of 4 parts per million (ppm). Choose green tea over black tea. Brewed black tea has 3.7 ppm, whereas green tea has only 1.2 ppm. Avoid highly processed tea. Instant tea powder with lemon and sugar has 5.8 ppm. Decaffeinated green tea has 2.7 ppm.

should consult a physician about drinking green tea since it does contain vitamin K. Vitamin K can make warfarin ineffective. Dried green tea leaves have a very high concentration of vitamin K, but a cup of brewed green tea provides only a small amount, 0.03 mcg per 3.5 fluid ounces (roughly half a cup). Research published in the Journal of the American Dietetic Association in 1995 showed that tea is not a significant dietary source of vitamin K. Exercise caution mixing green tea and aspirin because they both prevent platelets from clotting. Using the two together may increase your risk of bleeding.