Drink black coffee daily? You can live longer with it, says study

Indian Express

19-06-2025

A cup of black coffee every morning may just be adding years to your life. A large-scale study by Tufts University, US, claims that drinking one to three cups of coffee daily can reduce all-cause mortality, particularly from cardiovascular causes. However, there's a catch: the benefits hold only when you are not adding sugar, flavourings or cream.
The study, which tracked subjects 1999 onwards, found that black coffee and coffee with very low levels of added sugar and saturated fat were associated with a 14 per cent lower risk of all-cause mortality as compared to zero coffee consumption. The same link was not observed for coffee with high amounts of added sugar and saturated fat. Drinking one cup per day was associated with a 16% lower risk of all-cause mortality. At 2-3 cups per day, the risk lowered by 17%.
Consumption beyond three cups per day was not associated with additional reductions. In fact, the link between coffee and a lower risk of death from cardiovascular disease weakened in those who drank more than three cups per day.
Why is the study significant?
Research on the benefits of caffeine, such as improved attention, appetite suppression, alertness and physical performance have been many. But this is the first which specifies the type of coffee — black — to be had and by how much. Since a typical cup of coffee (240 ml) provides approximately 100 mg caffeine, drinking up to two cups are safe.
This is also in line with an earlier study which found that individuals who drink coffee and sit for over six hours daily have lower mortality rates than non-coffee drinkers who sit for similar periods.
What's the big problem with coffee studies?
Dr V Mohan, Chairman, Dr Mohan's Diabetes Specialities Centre, Chennai, feels the problem with studies on coffee drinking is that none tell you that the results depend on several variables, like the kind of coffee taken, its amount and how it is consumed. 'For example, in the West, they have their coffee black but in India, it is made with milk and sugar. The role of artificial sweeteners is still not ascertained. A few human studies suggest they are safe but animal studies have linked them to obesity, an increased risk of Type 2 diabetes and changes in gut microbiota of mice,' he says.
Then there are many kinds of coffee, dilute, concentrated, Arabic, decaffeinated, caffeinated, all of which have different effects. 'In India, we also have coffee with different foods. In such a scenario, how do you tease out the effects of coffee?' he asks.
Is black coffee good for diabetes?
Only in moderation. One or two cups a day usually don't cause problems. 'But having five or six cups can backfire, especially when you're not sleeping enough. High caffeine intake increases adrenaline and cortisol levels, just like lack of sleep does. Together, they create a double impact on your glucose control. So, caffeine indirectly raises your blood sugar, too. Plus, excessive caffeine can lead to poor sleep quality — even if you do manage to get to bed on time. It becomes a cycle: less sleep, more coffee, more stress hormones, and higher blood sugar,' says Dr Mohan.
The ideal combination
Try reducing your caffeine to two cups a day — preferably before 2 pm. 'Then monitor your blood sugar. You'll likely see improvement within a week or two,' says Dr Mohan.