Gabe Mirkin, M.D.
Two recent studies show that too much caffeine may cause problems for some people.
Researchers at Queens University in Kingston, Ontario report
that caffeine, in coffee, tea, chocolate, and most colas, raises
blood sugar levels in healthy people and diabetics, which cannot
be reversed by exercise or weight loss (1).
When you eat, your blood sugar level rises. If it rises too
high, sugar sticks to cells, and once stuck on cells, it is converted
to sorbitol which destroys the cell to increase risk for heart
attacks, strokes, blindness, deafness, kidney failure and other
effects of diabetes. Anything that increases blood sugar levels
increases risk for diabetes. So, most doctors recommend
restricting refined carbohydrates, in sugar and flour. Exercise
and weight loss do not prevent this rise in blood sugar. These
studies were done with caffeine pills. Coffee may contain
nutrients, such as antioxidants, potassium and magnesium, that
may prevent the high rise in blood sugar.
A second study, from the Netherlands shows that
drinking coffee can raise blood pressure (2). High blood pressure markedly
increases a person’s chances of suffering a heart attack, stroke
and sudden death. The new guidelines state that normal blood
pressure should be below 120 when the heart contracts and 80
when it relaxes. That means the almost 91 percent of all North
Americans will eventually become hypertensive and suffer
increased risk for premature death. The authors reviewed 16
studies on coffee drinking and high blood pressure and found
that for most people, drinking coffee does not raise blood
pressure, but for some, even one cup of coffee can raise blood
pressure. If you drink coffee or any other caffeinated beverage regularly, it may pay to check your
blood pressure twenty minutes after a drink. Your blood
pressure is too high if it is above 120 over 80.
1) Diabetes Care, March
2005
2)Journal of
Hypertension, May 2005
10/6/05