Coffee is such a normal part of daily life that people don't often stop to consider that it is a beverage that may have an impact on health. For a diabetic, food and drink become inextricably intertwined with the issue of health because a diabetic must manage his blood sugar carefully. It's important for diabetics to understand the effects of coffee --- and there are several --- on this chronic disease.
Diabetes Basics
Diabetes is essentially a disease of sugar metabolism. According to PubMed Health, type 2 diabetes is the most common form of the disease. Type 2 diabetes is also known as adult-onset diabetes because it is mostly likely to affect people over the age of 45. The basic metabolic problem in this disease is that fat, liver and muscle cells do not respond normally to insulin, and sugar, which is the fuel for metabolic processes, does not get into the body cells. As a result, the sugar builds up in the blood --- hyperglycemia --- and the high sugar levels can cause a number of complications, including heart disease and diabetic retinopathy, a problem with vision that can lead to blindness. Risk factors for diabetes include obesity, a family history of diabetes, increasing age, high blood pressure, elevated blood lipids and African-American, Native American or Hispanic genetic heritage.
Coffee and Caffeine
Coffee contains hundreds of compounds besides caffeine. This means that it can have both positive and negative effects on a disease as complicated as diabetes. If the effect is specific to caffeine, other beverages or foods that contain caffeine will have a similar effect. Tea, soft drinks, chocolate, cocoa and some over-the-counter medications contain caffeine.
Coffee's Protective Effects
Coffee, according to the Harvard Medical School Family Health Guide, has a protective effect against diabetes. Heavy coffee drinkers are about half as likely to get diabetes as those who imbibe lightly. Coffee also raises C-peptide levels, which are used as indicators of insulin secretion in diabetic patients. But decaf --- not regular coffee --- improves the blood lipids that protect diabetics from heart disease. This is significant because heart disease is one of the complications of diabetes.
Blood Sugar and Insulin Resistance
Caffeine has a negative effect on insulin action in young, healthy adults, says Dr. Maria Collazo-Clavell, an endocrinologist who writes for the Mayo Clinic's Expert Answers, but it does not necessarily affect blood sugar levels unless you have diabetes. If you do, your blood sugar is likely to go up a little after meals. It only takes about 250 mg of caffeine to cause this increase --- the equivalent of 2 to 2-½ cups of caffeinated coffee.
Blood Pressure
A report in the March 2002 "Archives of Internal Medicine", part of the Johns Hopkins Precursors Study, noted that drinking one cup of coffee a day slightly raised blood pressure and found that when compared with non-coffee drinkers at baseline, people who drank coffee had a higher incidence of high blood pressure. The researchers, led by Michael Klag, M.D., M.P.H., concluded that while coffee tends to raise blood pressure slightly over time, it has only a small role in hypertension.
Heart Disease
Diabetics are at higher risk for cardiovascular disease, and high blood lipids --- fatty substances such as cholesterol -- also increase risk. Both regular coffee and decaf, says Harvard's Family Health Guide, tend to increase cholesterol, due to two compounds -- kahweol and cafestol --- that can be removed with paper filters during the brewing process. Drinks such as lattes, which are unfiltered, will still contain these compounds. But data from the Framingham Study, a multi-year research project, show that overall, coffee has no impact on developing heart disease. This study did note, however, that coffee's effects on men and women were different. Coffee had negative effects on total cholesterol and low density lipoproteins, or LDLs in men; a negative effect on either increases the risk of heart disease. In women, on the other hand, coffee had a positive effect on LDLs. This data was reported by a research team led by Peter Wilson, M.D., in the 1989 "Annals of Internal Medicine."
Warning
If you're a diabetic, drinking coffee can affect your disease in many ways. Discuss the matter with a health-care professional who can review your personal health issues.
References
- PubMed Health; Type 2 Diabetes; Ari S. Eckman, M.D., David Zieve, M.D., M.H.A.; May 2010
- Harvard Medical School Family Health Guide: Coffee's Health Benefits
- Mayo Clinic: Type 2 Diabetes Expert Answers; Caffeine: Does It Affect Blood Sugar?; M. Collazo-Clavell, M.D.; February 2010
- "Archives of Internal Medicine"; Is Coffee Consumption a Contributor to Cardiovascular Disease? Insights From the Framingham Study; Peter W. F. Wilson, et al.; 1989
- "Archives of Internal Medicine"; Coffee Intake and Risk of Hypertension: The Johns Hopkins Precursors Study; Michael J. Klag, et al.; March 2002
