Study Shows 3 to 6 Cups of Tea Daily Linked Reduced Risk of Death From Heart Disease
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Reviewed By Laura J. Martin, MD
June 18, 2010 -- People who drink a lot of tea or drink coffee in moderation are less likely to die of heart disease than coffee and tea abstainers, new research suggests.
The finding adds to the growing body of evidence suggesting that coffee and tea help protect against heart disease, but not stroke.
Researchers followed more than 37,000 people in The Netherlands for 13 years in one of the largest and longest studies ever to examine the impact of coffee and tea drinking on heart health.
They found that:
- People who drank three to six cups of tea per day had a 45% lower risk of death from heart disease than people who drank less than one cup of tea a day.
- Drinking more than six cups of tea a day was associated with a 36% lower risk of heart disease, compared to drinking less than one cup.
- People who drank more than two, but no more than four, cups of coffee a day had about a 20% lower risk of heart disease than people who drank more or less coffee or no coffee at all.
- Moderate coffee consumption was associated with a slight, but not statistically significant, reduction in death from heart disease, but neither coffee nor tea affected stroke risk.
Benefits of Black Tea
The study did not include people with known heart disease, so it is not clear if drinking coffee or tea is beneficial for them, study researcher Yvonne T. van der Schouw, PhD, tells WebMD.
"But for healthy people, it appears that drinking coffee and tea is not harmful and it may even offer some benefits," she says.
Several earlier studies have also found that drinking coffee or tea lowers the risk for heart disease.
In one, reported in 2008, women who drank four to five cups of coffee a day had a 34% lower risk of dying from heart disease while men who drank more than five cups had a 44% lower risk.
In another study published the same year, drinking green tea was associated with improved blood vessel function and lower heart disease risk.
But most of the people in The Netherlands study drank black tea, which is also consumed more than green tea in America.
The study appears in the latest issue of the American Heart Association journal Arteriosclerosis, Thrombosis and Vascular Biology.
"The perception has been that green tea is the 'healthy' tea, but this study suggests black tea may be just a good for the heart," University of Vermont professor of nutrition Rachel K. Johnson, PhD, tells WebMD. "That will be good news to people like me who are not big green-tea lovers."
Flavonoids in Tea, Coffee May Protect Heart
While six cups of tea may sound like a lot, Johnson points out that a large glass of iced tea may contain two to three cups of liquid.
"Iced tea is very popular in some parts of the country, especially in the summer," says Johnson, who is also a spokeswoman for the American Heart Association. "Just make sure to go easy on the sugar. I would hate for people to get the message that they should be drinking more sugar-sweetened beverages."
The researchers suggest that powerful antioxidants called flavonoids found in black and green tea and coffee may explain the protective effect seen in the study.
Other foods that contain flavonoids include red wine, red grapes, dark chocolate, blueberries, and red beans.
SOURCES: de Koning Gans, J. Arteriosclerosis, Thrombosis, and Vascular Biology: Journal of the American Heart Association, August, 2010; online edition.
Yvonne T. van der Schouw, PhD, professor of chronic disease epidemiology, Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, The Netherlands.
Rachel K. Johnson, PhD, professor of nutrition, University of Vermont; spokeswoman, American Heart Association.
News release, American Heart Association.
Annals of Internal Medicine, June 16, 2008; vol 148; p 913.
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