Is green tea good for your health?

Posted Jun 4, 2007 by Bart B. Van Bockstaele

Many people drink green tea because they have heard fantastic health claims in the media, but how healthful is green tea really?
The last few years, the media have literally bombarded us with health claims regarding green tea. It seems indeed that green tea is used for treating an impressive list of ailments, including adenocarcinoma (cancer starting in the epithelial lining of gland-like organs), alcohol intoxication, atherosclerosis (deposition of atheromas (fatty deposits) on arterial walls), autoimmune encephalomyelitis (inflammation of the spinal cord and the brain, caused by a malfunction of the immune system), bladder cancer, bleeding of gums or tooth sockets, cataracts (clouding of the eye lens), coronary heart disease, Crohn's disease (type of inflammatory bowel disease), dementia, diarrhea, fibrosarcoma, flatulence, fungal infections, gastritis, gingivitis, gum swelling, headache, heart disease, Helicobacter pylori infection, HIV/AIDS, joint pain, liver cancer, lung cancer, lymphocytic leukemia, oral leukoplakia (white patches on mucous membranes), ovarian cancer, Parkinson's disease, stomach disorders, tired eyes, vascular tumors and vomiting.
Besides that, green tea is also used for bone density improvement, cognitive performance enhancement, detoxification from alcohol or toxins, digestion improvement, improving exercise performance, blood flow improvement, improving resistance to disease, improving urine flow, inhibition of platelet aggregation, ischemia-reperfusion injury protection, kidney stone prevention, longevity improvement, neuroprotection, prevention of Parkinson's disease, protection against asbestos lung injury, regulation of body temperature and stroke prevention.
Green tea is also recommended as an antioxidant, astringent, diuretic (increasing urine) and stimulant.
Impressive, but what does science tell us? Well, it tells us that a fairly large number of studies have been done regarding the use of green tea for treating, preventing or improving several conditions, namely anxiety, arthritis, asthma, cancer prevention, dental cavity prevention, diabetes, fertility, heart attack prevention, high cholesterol or triglycerides, memory enhancement, menopausal symptoms, mental performance and alertness, prostate cancer, sun protection and skin damage, weight loss and weight loss maintenance.
These studies have lead to a very impressive number of results. How many results? One. All other studies were either of such low quality that they are not reliable or the simply did not lead to any clear results.
Now, that one result must be a good one, right? Well, that is a matter of opinion. The study has lead to the conclusion that there is fair scientific evidence that green tea should not be used in the treatment of anxiety.
Besides these studies, there are a number of contraindications for drinking green tea:
*Green tea contains caffeine and tannins. Some people are allergic or hypersensitive to caffeine and tannins and they should avoid it.
*The tannins and polyphenols in green tea can cause iron deficiencies.
*The vitamin K in green tea can reduce the effectiveness of the anticoagulant Warfarin.
*People with severe liver deficiencies or diabetes should be careful drinking green tea and other caffeine containing beverages.
These contraindications should however not be taken too strictly. They are only important for people with fairly severe issues and then only when drinking fairly large amounts of tea. Most side-effects can be offset by adjusting the diet. Iron absorption can be improved by increasing vitamin C consumption. The effectiveness of Warfarin can be adjusted by increasing the dosage. A small cup or two of green tea a day has not been proven to harm anyone.
What does this all mean? It means that we should not confuse use in treatment with results. It is not because the media and all types of alternologists and even doctors recommend green tea that it has any demonstrated benefits.
What is the conclusion? People who drink green tea for their health are misguided. The only valid reason to date to drink green tea is that you like it. Most people who drink it don't like it. However, it is certainly possible to like green tea, as long as it is well prepared. Recommendations for how to properly prepare green tea can be found here.
A last word: I realize that many people will not be happy with what I wrote and that this will shock many. As someone who loves Japanese green tea, and who drinks it daily, I would have preferred bringing another message. But the truth is the truth. The claimed benefits of green tea are totally unproven. I have been collecting data on and of for several years on this subject. This article is the result. It is also the viewpoint of the National Centre for Complementary and Alternative Medicine, a division of the National Institutes of Health, a very official organization. Their conclusion can be found when clicking on the link below.