TEA AND THE HEART

A US study has shown that drinking at least one cup of tea a day can reduce the risk of heart attack by 44%. The health benefits are thought to be derived from ingredients known as flavanoids, a type of antioxidant found in all types of tea. Flavanoids are thought to neutralise the effect of free radicals, a highly reactive molecule which travels around the body causing chemical reactions which can damage cells, including those in the heart tissues.

A previous Dutch investigation of more than 800 men between 65 and 84 showed that drinking even more tea - between three and four cups a day - decreased risk of death from coronary heart disease by 58%. Another study has shown that drinkers of one or more cups of black tea a day are 40% less likely to suffer a heart attack than non-drinkers, whilst coffee seems to have no significant effect on heart attack risk (American Journal of Epidemiology 1999;149:162-167). Numerous studies have proved the cardiovascular benefits of green tea. But black tea also has benefits for the heart say researchers from the University of Arizona. A study of 3,430 adults in Saudi Arabia found that those who drank more than 6 cups per day of black tea had a more than 50% lower risk of coronary heart disease compared to tea abstainers, even after adjusting for other factors such as smoking, diet and obesity.

Antioxidants called flavonoids, found in both green and black teas, are thought to help reduce blood pressure, hardening of the arteries and the amount of LDL or ‘bad’ cholesterol in the blood stream. (Preventive Medicine 2002;36:64-70).

The British Medical Journal has published a Japanese study on the benefits of green tea consumption in preventing cardiovascular disease, liver disorders and possibly cancer. The study, begun in 1986, concerned 1371 men over the age of 40. Tea consumption was classified as less than 3 cups, between 4 and 9 cups, and over 10 cups per day. It was found that consumption of green tea was significantly associated with lower serum concentrations of lipids and lipoproteins. "An increase in consumption substantially decreased serum total cholesterol and triglyceride concentrations, and this strong association remained almost unaltered even after age, cigarette smoking, alcohol consumption and relative body weight were controlled for". Interestingly it was found that those who drank the most green tea (more than 10 cups) were also the heaviest smokers, but that whilst levels of lipid peroxides were generally higher among smokers than non-smokers, those smokers who drank more than 10 cups had lipid peroxide levels similar to non-smokers. The study also showed that consumption of green tea reduced liver cell damage and resulted in slightly lower (but not abnormal) haemoglobin concentration. The study also suggests that green tea has protective effects on the development of cancer.