The team at Duke University Medical Center in North Carolina found a strong
correlation between caffeine intake at mealtime and increased glucose and
insulin levels among people with type 2 diabetes.
The American Diabetes Association says that at least 90 percent of the 17
million Americans diagnosed with diabetes have type 2, in which the body either
does not produce enough insulin or cells ignore the insulin, which the body
needs to convert food into energy.
The findings are significant enough that the researchers recommend people
with diabetes consider reducing or eliminating caffeine from their diets.
"In a healthy person, glucose is metabolized within an hour or so after
eating. Diabetics, however, do not metabolize glucose as efficiently," said
James Lane, a psychiatry professor who led the study.
"It appears that diabetics who consume caffeine are likely having a harder
time regulating their insulin and glucose levels than those who don't take
caffeine."
Writing in the journal Diabetes Care, Lane and colleagues said they studied
14 habitual coffee drinkers with type 2 diabetes.
The researchers put the volunteers on a controlled diet.
They took their medications, had their blood tested and then were given
caffeine capsules. More blood was taken then and after giving the volunteers a
liquid meal supplement.
Caffeine had little effect on glucose and insulin levels when the volunteers
fasted, the researchers found.
But after the liquid meal, those who were given caffeine had a 21 percent
increase in their glucose level and insulin rose 48 percent.
"The goal of clinical treatment for diabetes is to keep the person's blood
glucose down," Lane said in a statement.
"It seems that caffeine, by further impairing the metabolism of meals, is
something diabetics ought to consider avoiding. Some people already watch their
diet and exercise regularly. Avoiding caffeine might be another way to better
manage their disease. In fact, it's possible that staying away from caffeine
could provide bigger benefits altogether."
