Human Biologist Studies Link Between Caffeine, Diabetes

By Lisa Caines
SPARK Program

Prof. Terry Graham is exploring the relationship between caffeine, found in drinks such as coffee and these boosting beverages, and type-2 diabetes.
PHOTO BY MARTIN SCHWALBE

Canadians resolving to cut their caffeine intake may reduce certain health risks as well, especially if obesity and lack of exercise play a role in diets that are high in caffeine.

Prof. Terry Graham, Human Biology and Nutritional Sciences, is part of a three-year tri-university effort researching the link between caffeine use and type-2 diabetes, the most common form of diabetes in Canada.

"The statistics in Canada and the western world are startling," says Graham. "Cases are becoming increasingly common and in younger age groups."

Type-2 diabetes is now common among people in their 40s, and increasing obesity in children suggests it will continue to affect younger age groups, he says.

Type-2 diabetes accounts for 90 per cent of diabetes in Canada. Those with the disease can still produce insulin - the body's blood glucose regulator - but Graham says they can't produce enough to "get the job done" and often have to take drugs to help manage blood sugar levels. He says the two biggest risk factors are inactivity and obesity.

"We're finding caffeine can have an unhealthy effect on insulin levels for people already at risk."

Graham's concern is based on his previous studies involving caffeine's impact on exercise metabolism using two groups of university-aged men - one group called "lean" and the other "obese." The subjects were tested using an oral glucose tolerance test, conducted with and without prior caffeine ingestion. This work was performed by graduate students Sara Chown, Heather Petrie and Laura Belfie.

"Ideally, you want to produce the least amount of insulin to get your body's glucose level down to normal," says Graham. "We found that obese individuals have a resistance to insulin, which means they require higher levels of insulin to adjust their glucose levels. When given caffeine, their insulin levels go through the roof."

This research focused on short-term effects of caffeine, but the new project will study some long-term effects surrounding caffeine and type-2 diabetes. It will involve obese and lean individuals between the ages of 40 and 60, with and without diabetes.

Among other long-term effects, the researchers will be looking for signs that the body adapts in habitual caffeine users.

"Caffeine is often thought of as a benign drug," says Graham, "and in many ways, it is. But from what we've seen so far, this research could lead to important potential treatment for diabetics."

Graham's research, in addition to involving a number of graduate students, involves research teams at two other Canadian universities (headed by Bob Ross and Bob Hudson at Queen's University and Arend Bonen at the University of Waterloo) and Mary Van Soeren, formerly of Guelph General Hospital.
This research is sponsored by the Natural Sciences and Engineering Research Council.