New research published in the European Journal of Preventive Cardiology shows that drinking tea at least three times a week is associated with have a longer and healthier life – so the claim is made. It appears that habitual tea drinking of this hot beverage is associated with reducing the risk of cardiovascular disease. Whilst it appears the benefits are more prominent with green tea drinkers rather than black tea drinkers there are benefits with this type of tea also.
The study conducted in China looked at 100,902 subjects taking part in the China-PAR project2, who had no record of disease conditions like stroke, cancer or a heart attack. Two groups were assessed – one group called habitual tea drinkers who were consumers of tea at least three times every week, and a group called non-habitual drinkers who drank tea less than three times every week. Both groups were followed for just over 7 years.
After that time period the researchers found that a middle aged tea drinker (lets say aged 50) would have a cardiovascular event such as heart disease or stroke on average 1.41 years later and lived 1.26 years longer than someone who had never or rarely drunk any tea.
The habitual tea drinkers also had a 20 per cent lower risk of heart disease and stroke, and more interestingly a 22 per cent lower risk of a fatal heart attack or other coronary event. These tea drinkers also had a 15 per cent reduced risk of any type of death (termed all-cause). The potential influence of changes in tea drinking behavior were analyzed in a subset of 14,081 participants with assessments at two time points. The average duration between the two surveys was 8.2 years, and the median follow-up after the second survey was 5.3 years.
The leading author Dr Xinyan Wang at the Chinese Academy of Medical Science in Beijing is quoted:-
“The favourable health effects are the most robust for green tea and for long-term habitual tea drinkers.”
We know that green and black tea contains good sources of polyphenols which are noted for their free-radical mopping up ability. They are also known to protect against various types of cardiovascular disease as well as certain types of cancer too. It seems however that there were no significant observations made for black tea which contradicts other research which highlights the benefits of this particular beverage. The study did reveal that green tea is by far the most popular of the tea beverages and the black tea drinkers were only 8 per cent of the total so their impact on the study would not be so statistically significant.
Black tea incidentally is fully fermented and during this process polyphenols are oxidized into pigments and bound up with tannins. This may reduce their antioxidant effects significantly. Also, black tea is often served with milk, which previous research has shown may counteract the favorable health effects of tea on vascular function.
There is a also a gender element to this study. A gender-specific analyses showed that the protective effects of habitual tea consumption were pronounced and robust across different outcomes for men. The effect for women was much more modest but there were still benefits to be noted.
Dr. Wang stated:
“One reason might be that 48% of men were habitual tea consumers compared to just 20% of women. Secondly, women had much lower incidence of, and mortality from, heart disease and stroke. These differences made it more likely to find statistically significant results among men..”
A note of caution though beware of medical confounding ! This was a study in a Chinese population and there may be issues in relating such evidence to other types of population.