Can consuming tea regularly reduce the risk of type-2 diabetes? A meta-analysis of 19 studies with over 10 lakh participants has shown that drinking four cups of tea a day can lower the risk of diabetes by 17 per cent. Drinking one to three cups of tea was associated with a four per cent lower risk of diabetes.
The researchers, who presented the finding at a conference recently, said that the finding held regardless of the type of tea consumed, gender of the person and geography. Only the amount of tea consumed was the significant determinant of diabetes risk.
This and several other such studies, however, do not give doctors the confidence to actually “prescribe tea” so to say. India, which is a nation of tea drinkers, then should logically have a lower diabetes burden which it does not. Despite several studies over the years on consumption of tea and coffee, the evidence is not conclusive, said Dr SV Madhu, professor of endocrinology at Guru Teg Bahadur Hospital. “There have been several studies over the years that have shown positive associations of tea and coffee with lower risk of diabetes – in fact, coffee more so than tea. But the studies have shown only association, there is no conclusive evidence that consuming tea and coffee is what leads to lowering of diabetes risk,” said Dr Madhu.
He added, “What this means for us practitioners is that we won’t prescribe it to someone who is healthy or pre-diabetic to keep diabetes at bay, but if someone is consuming tea and coffee, we will say that they may continue to do so.”
Without a randomised control trial – the gold standard of clinical trials – there is no way of proving that one thing causes the other. In cohort studies, or the meta-analysis of such studies, experts say can be affected by several variables – for example, the coffee or tea drinkers might be the ones who exercise regularly which will also reduce risk for diabetes.
Even though tea consumption has been found to be beneficial, what kind of tea you consume will have an impact. The meta-analysis here looked at different types of teas such as black and oolong, but when it comes to India tea is very different. “We have to look at what tea the studies have considered. In most studies when they mean tea, it is the leaves seeped in water. In India, however, tea means a concoction with milk and sugar. Drinking a sugary tea, four times a day, will defeat the whole purpose and lead to an increase in sugar levels of diabetics,” Dr Madhu said.
Instead, he added, people should focus on already proven lifestyle interventions.
“The most important thing is to have a healthy diet – no processed foods, or foods with too much salt, sugar, and fats – exercise every week, and a good sleep,” said Dr Madhu, adding everyone should take up some activities to lower stress levels as well.
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