Healthcare (Commonwealth Union) – The health benefits of tea have long been established over many decades. Green tea has been the main focus for health benefits, however black tea also has many benefits against certain types of cancer, its ability to lower blood sugar levels and its impact on cardiological health have been well established. The key difference between black tea and green tea is its processing method.
A recent study had found that individuals who drink tea have a lower chance of having heart disease and disease of the blood vessels than individuals who rare occasions or never consume tea. These were the findings of a large study that appeared this month in the Journal of Internal Medicine. The researchers however made a cautionary note pointing out that the work demonstrates a statistical link not a demonstrated advantage.
Researchers at Peking Union Medical College, led by Dr Zichen Ye, tracked nearly 486,000 adults in China (485,934) over a mean follow-up of roughly nine years. By the end, 14,863 of them had been diagnosed with vascular disease, a wide-ranging category covering coronary heart disease, cerebrovascular conditions such as stroke, pulmonary heart disease, and peripheral artery disease.
People consumed tea on a frequent basis had a 11% lower likelihood than those who did not consume tea on a frequent basis to get one of these conditions. The figure is relative. That tells us how the two groups did against each other, not how many individual cases would be prevented.
The researchers also looked at how tea compared to other habits. Together, tea consumption, smoking status and physical activity were associated with vascular risk. The lowest risk was seen in people who drank tea, didn’t smoke and were physically active. Tea alone could not explain the pattern.
Researchers not involved in the study welcomed the large sample but stressed its limits.
The main problem is one that besets most research on food and drink. Observational studies simply track what people are already doing rather than assigning them to a habit. People who drink tea every day may also differ in what they eat, how much money they have, how they socialise, how much they exercise and how closely they look after their health. Statistical adjustment can narrow those differences but rarely eliminates them altogether.
The results are also linked to data from China, where the kinds of tea, brewing techniques and drinking habits may vary compared to other nations. That means the results may not translate neatly to people in other places.
The message from the experts was consistent. The study usefully adds to the evidence but there is no reason to start drinking large amounts of tea hoping to protect the heart. The six to eight cups figure should not be taken as advice.
For tea drinkers, the research offers small comfort that the habit is unlikely to do any harm and can happily sit within a heart-healthy lifestyle. The suggestion that drinking very hot tea may be an added risk is early, but it is reasonable to let a drink cool a little before sipping. To prove if tea itself protects the heart, different evidence, such as trials that assign people to different intakes over time, would be needed.
