Green tea, coffee reduce diabetes death risk: Study

Green tea

Green tea is known to prevent cardiovascular disease, contains healthy bioactive compounds and has antioxidants called polyphenols that may lower the risk of some cancers.

Photo credit: Fotosearch

What you need to know:

  • Survival rate was recorded highest among individuals who took four or more cups of green tea and two or more cups of coffee daily.
  • The world marked Diabetes Day on November 14.
  • Obesity is the leading risk factor for diabetes.



Cases of diabetes are rising at an alarming rate. The World Health Organization (WHO) estimated that 26 per cent of bed occupancy in Kenya is due to diabetes while half of all kidney patients have diabetes.

However, despite the alarm, there is hope for patients with type 2 diabetes. Two new studies released as the world marked this year’s Diabetes day have shown the risk of death from type 2 diabetes can be significantly reduced.

The first study, conducted by Japanese scientists from Kyushu University and Hakujyuji Hospital, showed that taking green tea and coffee significantly reduced the risk of death in people with diabetes type 2. 

During the study period, the participants provided details on their diet and how regularly they consumed green tea and coffee. Over the period, 309 participants died from type 2 diabetes.

“However, we found out that the individuals who took more than one cup of green tea or coffee per day had a lower risk of death in comparison to those who did not take any of these. Individuals who took both green tea and coffee daily had an even lower risk of death with a mortality risk reduction of nearly two-thirds,” said the researchers in their report published in the journal BMJ Open Diabetes Research and Care.

Some cancer

The survival rate was recorded highest among individuals who took four or more cups of green tea and two or more cups of coffee daily.

According to Dr Geoffrey Njau, a public health practitioner in Nakuru, the discovery of green tea as a factor reducing deaths adds to the multiple health benefits it currently offers. “Green tea is known to prevent type 2 diabetes. That it can now cut mortality risk is an added advantage. This product also prevents cardiovascular disease, contains healthy bioactive compounds and has antioxidants called polyphenols that may lower the risk of some cancers,” he says.

In the second study conducted by scientists from University of Wisconsin Madison, a new way to stimulate the production of insulin in cells was discovered. “On one hand, too much insulin can lower blood sugar to dangerous levels. On the other hand, too little insulin can lead to diabetes. Individuals with type 2 diabetes have the dysfunctional metabolism from producing inadequate insulin,” said Dr Matthew Merrins, a professor of medicine who led the study.

“We now have the capacity to rewire metabolism to more efficiently trigger insulin production while improving the function of other organs simultaneously.” The findings were published in the journal Cell Metabolism.

Control blood sugar

Dr Njau explained that type 2 diabetes was mainly distinguished from type 1 diabetes by the way the body behaves towards insulin – a hormone produced in the pancreas to help the body use glucose or sugar for energy.

In type 1 diabetes, patients no longer produce insulin and are required to inject it as a way of controlling blood sugar levels. In type 2 diabetes, fat, liver and muscle cells reject insulin.

Currently, obesity is the leading risk factor for diabetes, and is estimated to account for between 80 and 85 per cent of the risk of developing type 2. “Overweight and obesity increase the risk for raised blood glucose levels and high blood pressure,” he said.

In addition, data from the Ministry of Health shows that at least 27 per cent of Kenyans are either overweight or obese. A total of 38.5 per cent of these are women while 17.5 per cent are men.

In the same vein, the World Obesity Federation report on obesity in Kenya shows that 8.4 per cent of children aged five to nine or 670, 834 children are likely to be obese by 2030.