Cutting down on caffeine could help people with type 2 diabetes control their blood sugar levels, according to a new study by scientists at Duke University Medical Center.

The researchers studied a small group of people with established type 2 diabetes who drank at least two cups of coffee everyday and who were trying to manage their disease through diet, exercise and oral medications, but no insulin. Scientists used new technology — a tiny glucose monitor embedded under their abdominal skin — to continuously monitor sugar levels over a 72-hour period.

Participants took capsules containing caffeine equal to about four cups of coffee on one day and then identical capsules that contained a placebo on another day.

The researchers found that when the participants consumed caffeine, their average daily sugar levels went up eight percent. Caffeine also exaggerated the rise in glucose after meals — increasing by nine percent after breakfast, 15 percent after lunch and 26 per cent after dinner.

"We’re not sure what it is about caffeine that drives glucose levels up, but we have a couple of theories," said lead author of the study Dr. James Lane from Duke University Medical School in a news release.

"It could be that caffeine interferes with the process that moves glucose from the blood and into muscle and other cells in the body where it is used for fuel. It may also be that caffeine triggers the release of adrenaline — the ‘fight or flight" hormone that we know can also boost sugar levels."

There are no current guidelines suggesting diabetics shouldn't’t drink coffee, but Lane said that day may soon come.

"Coffee is such a common drink in our society that we forget that it contains a very powerful drug — caffeine. Our study suggests that one way to lower blood sugar is to simply quit drinking coffee, or any other caffeinated beverages. It may not be easy, but it doesn't’t cost a dime, and there are no side effects," said Lane.

The findings appear in the February issue of Diabetes Care.