Understanding the glycemic index can help you choose foods that help stabilize rather than raise your blood sugar levels. Since blood sugar levels determine whether you have diabetes, keeping your numbers low helps you avoid the host of health problems that come with diabetes. The glycemic index measures the effects of certain foods on blood sugar. Carbohydrates cause a rise in blood sugar levels, while proteins and fats generally do not. Since butter is a fat, its glycemic index is zero.
Definition
The glycemic index assigns a numeric value to foods based on how quickly they raise your blood sugar levels after eating. Pure glucose is assigned a value of 100, with all other carbohydrates assigned numbers based on their breakdown compared to glucose. Foods with a glycemic index over 70 are considered to have a high glycemic index, while those with a GI under 55 are considered low GI. The lower the glycemic index, the slower the rise in blood sugar after eating. The amount of carbohydrate in a food does not always correlate with its glycemic index. Some fruits, for example, are pure carbohydrate but have a low GI. The glycemic index applies only to carbohydrates, not to proteins and fats like butter.
Mechanism
All carbohydrates must break down into glucose before they can be absorbed into cells as an energy source. Fats like butter do not break down into glucose, so they don't stimulate a rise in blood sugar. Bile salts break fat down into fatty acids and cholesterol.
Butter and Insulin
Butter and other fats may, in large amounts, cause insulin resistance, according to Jennie Brand-Miller, Ph.D., author of "The New Glucose Revolution." Although the reasons for the impaired insulin response is not yet well understood, animal studies such as a European study published in the February 2009 issue of "Diabetes/Metabolism Research and Reviews" show that different types of fats may cause different degrees of insulin resistance.
Insulin resistance develops when cells do not respond normally to insulin. The pancreas must produce increasing amounts of insulin to get cells to respond; eventually, insulin-producing cells "burn out" and the pancreas doesn't produce enough to remove glucose from the blood. Blood glucose levels rise, which can lead to Type 2 diabetes. Over time, high insulin levels can lead to development of the metabolic syndrome, a combination of excess weight around your waist, high cholesterol, high blood pressure and high blood sugars.
Butter's Effect on a High GI Meal
Eating butter with carbohydrates can reduce the glycemic index of a meal. Fats slow absorption, so eating fats with carbohydrates increases the amount of time it takes for a meal to break down and be absorbed, which lowers the glycemic index.
References
- "The New Glucose Revolution"; Jennie Brand-Miller; 2005
- Land O Lakes: Unsalted Butter
- Harvard School of Public Health: Carbohydrates: Good Carbs Guide the Way
- National Institute of Diabetes and Digestive and Kidney Diseases; Your Digestive System and How It Works; April 2008
- "Diabetes/Metabolism Research and Reviews"; Medium-Chain Fatty Acids Ameliorate Insulin Resistance Caused by High-Fat Diets in Rats; S. Wein, et al.; February 2009
