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 personís 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
2)Journal of Hypertension, May 2005