When we eat, the carbohydrates in our food become glucose in our blood; this period of time after we eat is known as postprandial. Blood glucose concentration following a meal is primarily determined by digestion and absorption of carbohydrates and its clearance from the circulation. Insulin secretion normally maintains blood glucose, but in individuals with diabetes, defects in insulin action or insulin secretion, impair regulation of postprandial glucose. Both the quantity and the source of carbohydrate influence postprandial glucose levels.Foods high in carbohydrates, like rice, potatoes and corn cause blood glucose levels to spike. People with diabetes have to manage their intake of carbohydrates to avoid these spikes. Controlling blood glucose to achieve normal or near-normal levels through food and nutrition interventions is the primary goal of diabetes management.Here are some common terms that should help you understand foods role in blood sugar control:Glycemic Index
The glycemic index of foods was developed to compare the postprandial blood sugar to constant amounts of different carbohydrate-containing foods. The glycemic index of a food is the increase above fasting in the blood glucose two hours after ingestion divided by the response to a reference food (usually glucose or white bread). The glycemic loads of foods, meals, and diets are calculated by multiplying the glycemic index of the foods by the amounts of carbohydrate in each food and then totaling the values for all foods.Low Carbohydrate Diet
It is recommended that people with diabetes have around 130 grams of carbohydrates per day. The focus of a low-carbohydrate diet is to restrict the total carbohydrate intake to less than the recommended amount. Low-carbohydrate diets might seem to be a logical approach to lowering postprandial glucose; however, foods that contain carbohydrate are important sources of energy, fiber, vitamins, and minerals as well. Therefore, a low carbohydrate diet is not recommended in the management of diabetes.
Foods with high levels of fiber, fructose, lactose, and fat tend to have a lower glycemic response; therefore people try to focus their meals around these foods. Solely focusing on these foods is not recommended for the management of diabetes as there have been noted potential methodological problems with the glycemic index.Sweeteners
Sugar alcohols are artificial sweeteners that contain half the calories of sucrose and have a lesser impact on blood sugar. Reduced calorie sweeteners approved by the FDA include sugar alcohols (polyols) such as erythritol, isomalt, lactitol, maltitol, mannitol, sorbitol, xylitol, tagatose, and hydrogenated starch hydrolysates. The use of sugar alcohols appears to be safe; however, they may cause gastric upset, especially in children.
The FDA has approved five nonnutritive sweeteners for use in the U.S. These are acesulfame potassium, aspartame, neotame, saccharin, and sucralose. Before being allowed on the market, all underwent rigorous scrutiny and were shown to be safe when consumed by the public, including people with diabetes and women during pregnancy.It's important to test your own reaction to any food containing sugar alcohols because blood sugar responses vary from person to person.Net CarbsThe term "net carb" refers to some types of carbohydrates that do not affect blood sugar and insulin the way other types do. Therefore, you can subtract these carbohydrates from a food's total carbohydrate count. For example, the carbohydrates in potatoes are converted almost instantly into glucose while foods that contain more fiber like whole grains are absorbed more slowly or may not be digested at all. When a food contains 5 grams or more of fiber, it is an accepted practice to subtract half the grams of fiber from a food's total carb count.Food claims
The FDA regulates claims about the sugar content in foods. "Sugar free" means the product contains less than .5 grams of sugar per serving. "Reduced" sugar means a serving has at least 25 percent less sugar than the regular version of that food. "No added sugar" means that the product may contain natural sugars, such as those found in fruit and milk, but any additional sweeteners are artificial.While carbohydrates are the main nutrient involved in blood glucose control, it is important to remember that carbohydrates are still a very necessary part of a healthy diet.
- Fruit: a natural carbohydrate source that provides vitamins, minerals, and fiber.
- Vegetables: a low carbohydrate food that also provides fiber, vitamins and minerals that are difficult to obtain from any other food source.
- Milk and Dairy: natural carbohydrates sources which also provide calcium
A dietary pattern that includes carbohydrate from fruits, vegetables, whole grains, legumes, and low-fat milk is encouraged for good health. A registered dietitian can help you determine how many carbohydrates to eat at each meal for a balanced diet.
Navalee Loriston, MS, RD, LDN