Cutting down on caffeine could help people with the most common form of diabetes better control their blood sugar levels, researchers said on Monday.

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

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

Caffeine is found in coffee, tea and many soft drinks. - See Caffeine ups blood sugar level in diabetics: study for the full report.