Drinking tea could lower your risk of stroke, but only if it’s not too hot

Regular tea drinking is linked to a lower risk of vascular diseases such as stroke, coronary heart disease and heart attack, according to a new study. ADVERTISEMENT ADVERTISEMENT Tea is made by steeping the processed leaves of Camellia sinensis, an evergreen shrub native to East Asia. All varieties —including white, green, oolong, black and pu-erh— come from this single plant, with their distinct flavours determined by how much they oxidise. The beverage is a regular part of the diet in many cultures. From the English breakfast to Chinese tea ceremonies, it is present in the daily lives of millions of people worldwide. Tea’s bioactive compounds, including polyphenols and flavonoids, have antioxidant, anti-inflammatory and endothelial-protective properties that preserve the inner lining of blood vessels and maintain healthy circulation, all of which can help prevent vascular diseases, according to a study published in the Journal of Internal Medicine. Researchers followed nearly 500,000 Chinese people for an average of nine years, recording their tea consumption and any diseases that developed during that period. They found that those who drink tea regularly three or more times a week showed 11.2% lower overall risk of vascular disease. The strongest association was for ischaemic stroke with a 36.6% reduction, followed by cerebrovascular disease at 19.1%. The protective associations varied substantially depending on how the tea was prepared and consumed, the researchers found. Among participants, the median intake was between two and three cups a day; however, the lowest associated risk was in those who consumed six to eight cups daily. Black tea showed the strongest and most consistent association with vascular diseases, followed by green tea. Researchers attribute this to the fermentation-derived compounds, such as theaflavins, which have anti-inflammatory and lipid-regulating properties. The temperature and strength of the brew also made a difference. Researchers found that the best combination was moderately strong and non-scalding tea. Surprisingly, burning hot tea was linked to the opposite effect: a 16% increase in vascular disease risk. Very hot drinks have previously also been associated with a greater likelihood of oesophageal cancer. Tea is not a silver bullet The protective association of habitual tea consumption was consistent across most demographic subgroups but was significantly stronger in individuals with obesity, the researchers noted. Despite these results, the authors warn that drinking tea alone does not protect against cardiovascular disease and that it should form part of a broader healthy lifestyle and complement established prevention strategies. “This was an observational study and other differences in people’s diets and lifestyles could help explain the findings,” said Dell Stanford, senior dietitian at the British Heart Foundation who did not participate in the study, adding that the results don’t prove “that a daily cuppa protects your heart.” Cardiovascular disease remains the leading cause of illness and mortality in the European Union, accounting for one in three of all deaths and affecting an estimated 62 million people.