For those of you that love your tea or coffee, some encouraging news on the link between tea/coffee consumption and heart disease.
Between three and six cups of tea a day may reduce the risk of death from heart disease by about 45 per cent, says a new study from The Netherlands.
And drinking coffee, may offer similar benefits, with between two and four cups of day associated with a 20 per cent reduction in risk, according to findings published in the journal Arteriosclerosis, Thrombosis, and Vascular Biology.
The researchers proposed that the benefits of the beverages may be due to their antioxidant content, with the flavonoids in tea, in particular, thought to contribute to reduced risk. They note, however, that the underlying mechanism is still not known.
The benefits of bean and leaf
Interest in both tea and coffee is increasing, with the number of scientific papers reporting potential benefits growing. In a recent paper in Physiology & Behavior(doi: 10.1016/j.physbeh.2010.01.035), Mario Ferruzzi from Purdue University stated:
A better understanding of how the beverage composition impacts phenolic profiles and their bioavailability is critical to development of beverage products designed to deliver specific health benefits.
The new study does not deepen our understanding of the beverages’ compositions, but it does appear to strengthen the potential heart health benefits of coffee and tea.
Scientists led by Professor Yvonne van der Schouw used a questionnaire to quantify the consumption of tea and coffee in 37,514 participants of the Dutch cohort of the European Prospective Investigation into Cancer and Nutrition (EPIC).
During the 13 years of study, 1,881 cases of cardiovascular events were documented, with 563 strokes and 1,387 cases of coronary heart disease. Seventy deaths from stroke were documented and 123 from CHD, added the researchers.
After crunching the numbers, van der Schouw and her co-workers calculated that between three and six cups of tea a day may reduce the risk of death from heart disease by 45 per cent, while more than six cups was associated with a 36 per cent lower risk, compared with people who frank one cup or less per day. Black tea was the most common form of tea consumed in the Dutch cohort.
Between two and four cups of coffee a day were associated with a 20 per cent lower risk, compared to those who drank less than two or more than four cups per day, said the researchers.
All true tea plants (black, green, oolong) belong to the same species called Camellia sinensis. The quality of teas and their health benefits differ based on local growing conditions (altitude, climate, and soil) and the way the leaves are processed.
Green tea is the least processed and thus provides the most antioxidant polyphenols, including a catechin called epigallocatechin-3-gallate (EGCG), which is believed to be responsible for most of the health benefits linked to green tea. Hundreds of studies have evaluated the benefits of green tea for heart health, cancer prevention, bone health, diabetes, gum disease, brain health, weight loss, and much more.
Certain types of green tea contain higher levels of nutrients, and they are also much more expensive than regular green tea. For example, Matcha green tea is made from the finest, youngest leaves of the first harvesting days in Japan.
Most of the research on the health benefits of green tea is based on the amount of green tea typically consumed in Asian countries—about 3 cups per day.
In 2007 the USDA compared nearly 400 kinds for their flavonoid content, which is mainly responsible for green tea’s health benefits. They found that a cup of hot, regular (not decaffeinated or flavoured) green tea provided 127 milligrams of catechins, which is
- 2 times more than a decaffeinated green tea.
- 3 times more than a flavored green tea.
- 10 times more than an instant or bottled green tea!
Allow the tea to steep for three to five minutes to extract its catechins, most notably epigallocatechin-3-gallate.
Green tea is generally regarded as safe, however green tea extracts (supplement forms) are not recommended for those with liver failure. There are several case reports in which use of a concentrated green tea extract was associated with liver inflammation. In most cases, liver problems disappeared after the extract was discontinued. But, in two cases, permanent liver failure occurred. While it is not absolutely certain that the green tea extract caused the liver problems, nor how it might do so, these reports have raised concerns about use of green tea extracts, especially by those with liver disease.
Source: Arteriosclerosis, Thrombosis, and Vascular Biology
Published online ahead of print, doi: 10.1161/ATVBAHA.109.201939
“Tea and Coffee Consumption and Cardiovascular Morbidity and Mortality”
Authors: J.M. de Koning Gans, C.S.P.M. Uiterwaal, Y.T. van der Schouw, J.M.A. Boer, D.E. Grobbee, W.M.M. Verschuren, J.W.J. Beulens
Image courtesy of jkoldas