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Studies on tea and health

December 5, 2021

Wei Sheng Yan Jiu. 2011 Nov;40(6):802-5.

ABSTRACT

Many studies, both national and international, have shown that tea has protective effects on many chronic diseases and their risk factors. In cancer prevention, our studies indicated that tea drinking could inhibit the carcinogenicity of various chemical carcinogens, including oral tumors induced by 7,12-dimethylbenz[a]anthracene (DMBA) in Golden hamsters, esophageal tumors in rats by blocking in vivo synthesis of N-Nitroso-methylbenzylamine (NMBzA), esophageal cancer induced by NMBzA in rats, precancerous liver lesions (r-GT and GST-P) induced by diethylnitrosamine (DENA) in rats, intestinal preneoplastic lesion (ACF) and intestinal tumors induced by 1,2-dimethyl-hydrazine (DMH) in rats, lung carcinoma induced by nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone(NNK) in A/J mice. Our studies have also shown that the protective effects of tea against cancer is a combined effects of various tea ingredients, among which the major ones are polyphenols and tea pigments. Based on animal studies, antioxidant properties, protection against DNA damage and modulation of immune functions were found to be the main mechanisms of anticancer effects of tea. In human trials, tea drinking showed protective effects against oxidative damage and DNA damage caused by cigarette smoking. Mixed tea drinking significantly blocked lesion progress in patients with oral mucosa leukoplakia, therefore, demonstrated its protective effects on oral cancer. Our studies have also shown effects of tea on prevention of cardiovascular diseases (CVD). For example, tea pigments was found to significantly inhibit LDL oxidation induced by Cu2+, Fe2+ in in vitro studies. In vivo studies showed that tea could prevent blood coagulation, facilitate fibrinogen dissolution, inhibit platelet aggregation, lower endothelin levels, enhance GSH-Px activities, protect against oxidated LDL-induced damage in endothelium cells, and prevent atherosclerosis of coronary arteries. The mechanisms of these protective effects of tea are possibly related to its antioxidant properties or its inhibition of lipid oxidation. Green tea and pigments was also found to inhibit cardiac hypertrophy induced by renal hypertension in rat models, whose mechanisms might, at least partly, involve its modulation on nitric oxide, angiotensin II and endothelin-1. Clinical intervention trials have indicated that tea and tea extracts decreased blood lipid, improved blood flow of coronary artery, and played an important role in atherosis inhibition and prevention. Our studies also showed that tea drinking has protective effects on diabetes. White tea drinking could significantly relieve symptoms including polyuria, polydipsia, polyphagia and weight loss in diabetic mice, decrease fasting plasma glucose level and improve glucose tolerance. In human trial, continuous white tea drinking could significantly improve symptoms of diabetic patients, such as relieve polydipsia, decrease plasma glucose levels, both fasting and 2 hours after meal, and increase insulin secretion. The effective rate for glucose lowering is 48% in clinical study.

PMID:22279681

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Patrick Blanchard MD

Meet Dr. Blanchard Dr. Blanchard’s medical practice is an embodiment of Integrative health which brings conventional and complementary approaches together in a coordinated way. Conveniently located in sunny Florida and over the internet with ValiseMD’s secure HIPPA compliant telXmed servers. Since 1994, patients with a wide range of challenging medical problems have achieved optimum health using the best of natural medicine, judiciously combined with high-tech innovations. Breakthroughs are often achieved even after patients have consulted mainstream specialists and holistic practitioners. Dr. Blanchard is founder and CEO of ValiseMD, Inc. He is board certified in Family Medicine since 1994 and awarded Fellow of the American Academy of Family Physicians in 2001. He received the ‘Teacher of the Year’ award from the University of Kansas School of Medicine at completion of his residency in Family Medicine. He completed a fellowship at Wake Forest University in the field of vascular neurosonology. He holds a medical patent in the field of Gastroenterology. He holds an unrestricted license to practice medicine and surgery in Florida. He started his medical career as a Emergency Medical Technician, then as a Paramedic and later a Medical Doctor.