An estimated 785,000 Americans had their first heart attack in 2009 and 470,000 of them are likely to have a recurrent heart attack. High cholesterol, high blood pressure, obesity, diabetes, tobacco use, and secondhand smoke are all risk factors for heart disease.
We are fortunate because enjoying between 1 and 4 cups of green tea each day is heart-healthy and has no harmful side effects for most people. Researchers estimate 3 cups of green tea each day leads to an 11% decrease in the rate of heart attack. Another study found drinking 4 cups of tea per day significantly reduced the risk of death following a heart attack.
Kenneth J. Mukamal, of the Division of General Medicine and Primary Care at Beth Israel Deaconess Medical Center and his colleagues conducted a study on the effects of tea consumption on heart attacks.2 The “Onset Study” was conducted in 45 community hospitals and tertiary care medical centers in the United States. From August 1989 to September 1994, there were 1935 patients (601 women and 1334 men) interviewed approximately 4 days after having a heart attack. It is important to note that the tea drinking level was self-reported by patients and based on their tea drinking during the past year.
Researchers found that when heart attack survivors were heavy-tea drinkers they had a 44% reduced risk of dying during the 3.5 years after their heart attacks. The reduction was based on comparison of the death rates of non-tea drinkers in the study. Moderate tea drinkers realized a 28% reduction in the risk of dying as compared to those who do not drink tea. Dr. Mukamal found the highest response to tea-drinking came from patients already living with heart disease.
Cholesterol
Green tea will help lower low density lipoprotein (LDL) cholesterol and blood pressure and control obesity and diabetes. These are all risk factors for developing heart disease. Green tea, in combination with a low fat and low cholesterol diet may reduce LDL levels by 10%. Drinking green tea will also raise high density lipoproteins (HDLs), the “good” cholesterol, in the blood and lower total cholesterol.3
Quercetin is an antioxidant in the flavonol class of molecules present in green tea. Its properties contribute to its ability to oxidize LDLs. This is significant because oxidized LDLs are critical molecules in the process that makes plaque.4 Plaque is the build-up of calcium, fats and atheromas in the arteries. This condition is commonly called “hardening of the arteries” which narrows or completely blocks the flow of blood through hardened arteries. Drinking 4 cups of tea per day improves cell quality in the lining of the heart and blood vessels and strengthens the cardiovascular system.
Inflammation
Catechins, a class of flavonols found in green tea, have been studied for their beneficial effects in the prevention of autoimmune disorders and cancer, among other maladies. Recently, catechins were found to prevent inflammation as well. Inflammation in the cardiovascular system has been identified as a contributor to heart disease. Catechins help prevent or limit cardiovascular disease by stopping processes which make molecules that act as green lights for the inflammatory process to begin.
Some scientists have concluded “catechins are potent agents for the treatment and prevention of inflammation-related cardiovascular diseases because they are critically involved in the suppression of pro-inflammatory signaling pathways.”5
1Heart Disease and Stroke Statistics—2009 Update. A Report from the American Heart Association Statistics Committee and Stroke Statistics Subcommittee. Lloyd-Jones D, Adams R, Carnethon M, et al. Circulation. 2009.119:e21-e181.
2Tea Consumption and Mortality After Acute Myocardial Infarction. Kenneth J. Mukamal, MD, MPH, MA; Malcolm Maclure, ScD; James E. Muller, MD; Jane B. Sherwood, RN; Murray A. Mittleman, MD, Dr PH. Circulation. 2002.105:2476.
3 Heat-epimerized tea catechins rich in gallocatechin gallate and catechin gallate are more effective to inhibit cholesterol absorption than tea catechins rich in epigallocatechin gallate and epicatechin gallate. Ikeda I, Kobayashi M, Hamada T, Tsuda K, Goto H, Imaizumi K, Nozawa A, Sugimoto A, Kakuda T. 2003. J Agric Food Chem 51(25):7303–7.
4Bioavailability and health effects of dietary flavonols in man. PC Hollman and Katan, MB. Arch Toxicol Suppl. 1998. 20:237-48.
5Tea polyphenols regulate key mediators on inflammatory cardiovascular diseases.
Suzuki J, Isobe M, Morishita R, Nagai R. Mediators Inflamm. 2009:494928. Epub 2009 Jul 19.
