
- With Mayo Clinic endocrinologist
Maria Collazo-Clavell, M.D.
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Maria Collazo-Clavell, M.D.
Maria Collazo-Clavell, M.D.
Dr. Maria Collazo-Clavell is board certified in internal medicine, endocrinology, diabetes and metabolism. She's a consultant in the Division of Endocrinology, Diabetes, Metabolism & Nutrition at Mayo Clinic and an associate professor at College of Medicine, Mayo Clinic.
The Aibonito, Puerto Rico, native has been with Mayo Clinic since 1994.
She's a member of the American Association of Clinical Endocrinologists, the American College of Endocrinology, the American Diabetes Association and The Endocrine Society.
Dr. Collazo-Clavell is medical editor of diabetes content on Mayo's health information website and for "Mayo Clinic The Essential Diabetes Book." Her clinical interests include management of type 1 and type 2 diabetes, obesity and nutritional disorders.
Risk factors (1)
- Diabetes: Does alcohol and tobacco use increase my risk?
Symptoms (1)
- The dawn phenomenon: What can you do?
Complications (1)
- Diabetes: How do I help protect my liver?
Treatments and drugs (4)
- Diabetes management: Does aspirin therapy prevent heart problems?
- Blood glucose monitors: What factors affect accuracy?
- Avandia and Actos safety concerns: What should I do?
- see all in Treatments and drugs
Lifestyle and home remedies (10)
- Caffeine: Does it affect blood sugar?
- Glucosamine: Does it affect blood sugar?
- Diabetes: Are electric blankets off-limits?
- see all in Lifestyle and home remedies
Alternative medicine (2)
- Diabetes treatment: Can cinnamon lower blood sugar?
- Does prickly pear cactus have health benefits?
Question
Caffeine: Does it affect blood sugar?
Does caffeine affect blood sugar?
Answer
from Maria Collazo-Clavell, M.D.
Caffeine impairs insulin action, but doesn't necessarily affect blood sugar (glucose) levels in young, healthy adults. However, if you have type 2 diabetes, the impact of caffeine on insulin action may be associated with a small, but detectable rise in blood sugar levels, particularly after meals. About 250 milligrams of caffeine — or the equivalent of 2 to 2 1/2 cups (473 to 591 milliliters) of plain, brewed coffee — a day may cause this effect.
If you have type 2 diabetes and you're struggling to control your blood sugar levels, limiting the amount of caffeine in your diet may provide a benefit.
Next questionGlucosamine: Does it affect blood sugar?
- MacKenzie T, et al. Metabolic and hormonal effects of caffeine: Randomized, double-blind, placebo-controlled crossover trial. Metabolism. 2007;56:1694.
- Lane JD, et al. Exaggeration of postprandial hyperglycemia in patients with type 2 diabetes by administration of caffeine in coffee. Endocrine Practice. 2007;13:239.
- Tunnicliffe JM, et al. Coffee, glucose homeostasis, and insulin resistance: Physiological mechanisms and mediators. Applied Physiology, Nutrition and Metabolism. 2008;33:1290.
- USDA National Nutrient Database for Standard Reference, Release 24. U.S. Department of Agriculture. http://ndb.nal.usda.gov/. Accessed Jan. 31, 2012.
- Moisey LL, et al. Caffeinated coffee consumption impairs blood glucose homeostasis in response to high and low glycemic index meals in healthy men. American Journal of Clinical Nutrition. 2008;87:1254
- Greenberg JA, et al. Decaffeinated coffee and glucose metabolism in young men. Diabetes Care. 2010;33:278


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