A study has revealed that drinking tea no less than 3 times per week is associated with a healthier and longer life. Habitual tea consumption is linked to reduced cardiovascular disease risk as well as risks of all-cause death. These positive health effects are the strongest for drinkers of green tea and also for long-term habitual drinkers of tea.
The study involved 100,902 individuals without any history of stroke, cancer or heart attack who had participated in the China-PAR project2. Individuals were grouped into 2 types: tea drinkers who drank tea habitually 3 or more times per week, and those who never or seldom drank tea drinking under 3 times per week, with an average of 7.3 years follow-up. Habitual tea consumption was linked to a longer life expectancy and more healthy years of life.
For instance, it was estimated that habitual tea drinkers who were 50 years old would live 1.26 years longer and develop stroke and coronary heart disease 1.41 years later compared to individuals who seldom or never consumed tea. In comparison to individuals who never or seldom drank tea, habitual drinkers of tea had a 20% reduced risk of stroke and incident heart disease, a 22% reduced risk of stroke and fatal heart disease, and a 15% reduced risk of all-cause death.
The data from a subset of 14,081 individuals was analyzed with assessments at two different points in time to determine the potential influence of different tea drinking behaviors. The average length of time between the 2 surveys was 8.2 years, and the average follow-up after the 2nd survey was 5.3 years. There was a 39% reduced risk of stroke and incident heart disease in habitual tea drinkers maintaining their habit in both assessments, as well as a 56% reduced risk of stroke and fatal heart disease, and a 29% reduced risk of all-cause death when compared to those who consistently never or seldom drank tea.
The tea’s protective effects were most evident among the consistently habitual tea drinkers. Research has indicated that polyphenols, the main bioactive compounds in tea, aren’t stored long-term in the body. So drinking tea frequently over an extended period could be necessary to experience the cardioprotective effect. Green tea consumption was associated with an approximately 25% reduced risk of stroke and incident heart disease, stroke and fatal heart disease, and all-cause death. No significant associations were however observed for black tea consumption.
For the study, green tea was consumed the most frequently by 49% of the habitual tea drinkers, with only 8% of the habitual tea drinkers consuming black tea. The small percentage of drinkers of black tea could have made it harder for observation of strong associations, but the results hint at a degree of difference between the effects of the types of tea. There are 2 factors that could be at play: Firstly, green tea is an excellent source of polyphenols that are protective against cardiovascular disease and cardiovascular disease risk factors which includes dyslipidaemia and hypertension. The black tea fermentation process oxidizes polyphenols into pigments which could result in them losing their antioxidant effects. Secondly, prior research has revealed that the milk, which is usually served with black tea, could counteract the favorable health effects of tea on vascular function.
It was also revealed that the protective effects of consuming tea habitually were strongly evident for men, but only modestly so for women. There are two factors which made it more likely to find results for men that were statistically significant. It could be that 48% of men drank tea habitually in comparison to only 20% of women. It could also be that there is a much lower occurrence of, and mortality from heart disease and stroke in women.