The health benefits of green tea and coffee have been widely discussed for years. And now, a new study has found drinking green tea and coffee may help people with type 2 diabetes live longer.

The study published in the online journal BMJ Open Diabetes Research & Care on Wednesday found that drinking four or more daily cups of green tea plus two or more cups of coffee was associated with a 63 per cent lower risk of death over a period of five years. People with type 2 diabetes are more prone to circulatory diseases, dementia, cancer and bone fractures.

For the study, the researchers tracked the health of 4,923 Japanese people (2,790 men, 2,133 women) with type 2 diabetes for an average of just over five years. They each filled in a food and drink questionnaire, which included questions on how much green tea and coffee they drank every day.

During the monitoring period, 309 people died. The main causes of death were cancer and cardiovascular disease. The researchers found those who drank either green tea or coffee had lower odds of dying from any cause, with the lowest odds associated with drinking higher quantities of both green tea and coffee.

Drinking up to one cup of green tea everyday was associated with 15 per cent lower odds of death while drinking two to three cups was associated with 27 per cent lower odds. Getting through four or more daily cups was associated with 40 per cent lower odds.

Among coffee drinkers, up to one daily cup was associated with 12 per cent lower odds, while one cup a day was associated with 19 per cent lower odds, and two or more cups was associated with 41 per cent lower odds.

The risk of death was even lower for those who drank both green tea and coffee every day: 51 per cent lower for two to three cups of green tea plus two or more of coffee, 58 per cent lower for four or more cups of green tea plus one cup of coffee every day and 63 per cent lower for a combination of four or more cups of green tea and two or more cups of coffee every day.

While the results seem promising, the researchers highlighted that this is only an observational study, adding it also relied on people assessing their own tea and coffee consumption through a questionnaire, which can be unreliable.

“This prospective cohort study demonstrated that greater consumption of green tea and coffee was significantly associated with reduced all-cause mortality: the effects may be additive,” the researchers concluded.