Giving caffeine to a small group of people with type-2 diabetes caused the glucose levels in their blood to rise through the day, especially after meals, said researchers at Duke University Medical Centre in North Carolina.

'Caffeine appears to disrupt glucose metabolism in a way that could be harmful to people with type-2 diabetes,' said Dr James Lane, a psychologist who led the study.

The new findings seem to run counter to previous research which said that people who drank coffee had a reduced risk of type-2 diabetes, and those who drank the most coffee had the lowest risk.

The researchers used a tiny glucose monitor embedded under the abdominal skin to monitor the glucose levels continuously in 10 people with an average age of 63.

Dr Lane said caffeine may interfere with the process that transports glucose from the blood into muscle and other cells in the body to be burned as fuel, he said.

He added that caffeine also triggers the release of the hormone adrenaline, which can elevate blood sugar levels.

REUTERS