Tea for Healthier Heart and Stronger Bones
Medical journals have recently reported some good news for the billions of tea drinkers around the world: reduced risk of both heart attack and osteoporosis (thin bones) may result from drinking the beverage consumed more than any drink but water worldwide.
The first study examined the relationship between drinking black tea and the incidence of heart attacks in 4,800 men and women over the age of 55.1 Using questionnaires to determine the amount and duration of tea consumption over the course of almost six years, researchers found that people who drank more than 375 ml per day of black tea (approximately 12 ounces or 3 cups) had a 43% reduction in risk of heart attacks compared with non-tea drinkers.
The authors suggest the heart-healthy benefits of tea may be due to the fact that tea is a rich source of a group of substances called flavonols, which may improve heart function. However, more research is needed to clarify this issue. As an interesting side note, the researchers also found that tea drinkers with the highest intakes were thinner, smoked fewer cigarettes, were more educated, and had healthier diets. It is possible that these healthy lifestyle choices contributed to tea’s heart-protective effects; however, tea still had a protective effect after controlling for all of these other factors.
Another study evaluated whether compounds found in tea affected bone mineral density (BMD).2 More than 1,000 Chinese men and women were questioned about consumption of green, black, or oolong tea, in addition to other lifestyle characteristics. Measurements of bone mineral density of the total body, low back, and hip were also recorded. Those who consumed any kind of tea for 10 or more years had significantly higher total body, low back, and hip BMDs than did non-habitual tea drinkers. Drinking tea for 6 to 10 years increased low back BMD, compared with the BMD in those who drank tea for less than 5 years or not at all.
Although the average person drank 3.5 cups of tea per day, the authors found that the duration of tea consumption was more important in increasing BMD than the amount of daily tea intake. No significant differences were found between green, black, or oolong teas. The protective effect of tea against bone loss is surprising, considering that other studies have shown that caffeine consumption is associated with increased bone loss.3 Evidently, any negative effect of the caffeine is more than overcome by other components of tea.
All non-herbal teas come from the same plant (Camellia sinensis), but varies depending on how the plant is processed. Green tea is unfermented, while oolong tea is partially fermented and black tea is fully fermented, which ultimately affects taste. One should be aware that tea naturally contains caffeine, although the amount in tea is approximately one-quarter of the amount found in regular coffee. The caffeine content of black tea is slightly higher than that of green tea, due to the way the tea is processed.
1. Geleijnse JM, Launer LJ, van der Kuip DA, et al. Inverse association of tea and flavonoid intakes with incident myocardial infarction: the Rotterdam Study. Am J Clin Nutr 2002;75:880–6.
2. Wu C, Yang Y, Yao W, et al. Epidemiological evidence of increased bone mineral density in habitual tea drinkers. Arch Intern Med 2002;162:1001–6.
3. Rapuri PB, Gallagher JC, Kinyamu HK, Ryschon KL. Caffeine intake increases the rate of bone loss in elderly women and interacts with vitamin D receptor genotypes. Am J Clin Nutr 2001;74:694–700.
Darin Ingels, ND, MT (ASCP), received his bachelor’s degree from Purdue University and his Doctorate of Naturopathic Medicine from Bastyr University in Kenmore, WA. Dr. Ingels is the author of Garlic and Cholesterol: Everything You Need to Know (Prima, 1999) and Natural Treatments for High Cholesterol (Prima, 2000). He currently is in private practice in Southport, CT, where he specializes in environmental medicine and allergies. Dr. Ingels is a regular contributor to Healthnotes and Healthnotes Newswire.
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