Don't delay your care at Mayo Clinic
Featured conditions Brain tumor, breast cancer, colon cancer, congenital heart disease, heart arrhythmia. See more conditions.
Featured conditions
Mayo Clinic offers appointments in Arizona, Florida and Minnesota and at Mayo Clinic Health System locations.
Subscribe to Housecall
Our general interest e-newsletter keeps you up to date on a wide variety of health topics.
The average U.S. adult drinks about two 8-ounce (240-milliliter) cups of coffee a day, which can contain around 280 milligrams of caffeine. For most young, healthy adults, caffeine doesn't appear to noticeably affect blood sugar (glucose) levels, and having up to 400 milligrams a day appears to be safe.
Some studies suggest that drinking coffee — whether caffeinated and decaffeinated — may actually reduce your risk of developing type 2 diabetes.
If you already have diabetes, however, the impact of caffeine on insulin action may be associated with higher or lower blood sugar levels. For some people with diabetes, about 200 milligrams of caffeine — or the equivalent of one to two 8-ounce (240-milliliter) cups of plain, brewed coffee — may cause this effect.
Caffeine affects every person differently. If you have diabetes or you're struggling to control your blood sugar levels, limiting the amount of caffeine in your diet may provide a benefit.
With
M. Regina Castro, M.D.
Mayo Clinic does not endorse companies or products. Advertising revenue supports our not-for-profit mission.
Check out these best-sellers and special offers on books and newsletters from Mayo Clinic.