Glucose is a type of sugar and the most common carbohydrate found in many foods. Like all carbohydrates, with the exception of fiber, glucose can influence your glycemia, or blood sugar levels. The sugar that circulates in your blood is actually found in the form of glucose, which explains why the consumption of glucose can quickly elevate your glycemia.
Glucose in Foods
You can purchase pure glucose, which may be called dextrose, at your grocery store. It is a white powder, usually produced from corn. Glucose is also part of most sweeteners, combined with fructose. For example, table sugar, honey and maple syrup are 50 percent glucose; high-fructose corn syrup is 45 percent glucose. Fruits also contain varying proportions of glucose combined with fructose -- and starch actually corresponds to a large source of glucose in the American diet. Starch is made of a long chain of glucose units linked together and found in starchy vegetables, grains and legumes.
Glucose and Glycemia
If you consume pure glucose in the form of glucose powder, it doesn't have to undergo any digestion process and is ready to absorb as is. If you eat glucose in the form of sucrose, which is the same as table sugar, or in the form of starch, the enzymes produced in your gastrointestinal tract break down your food to obtain single molecules of glucose. The individual molecules of glucose go straight into your bloodstream where they increase the concentration of your blood glucose and create an elevation in your glycemia, or blood glucose levels.
Glucose and Glycemic Index
The glycemic index, or GI, measures the effects of different types of carbohydrates on your glycemia. Many foods rich in glucose tend to have a high glycemic index because they are quickly absorbed and cause a sharp rise in your blood glucose. The glycemic index ranks foods from 0 to 100 -- with pure glucose having the highest value of 100. The GI of other glucose-containing foods varies depending on the type of starch it contains, as well as the other combined nutrients and their degrees of processing.
Controlling Your Glycemia
To keep your glycemia in check, you will need to control your glucose intake. Many foods rich in glucose are not necessarily required for optimal health and you can eliminate them from your diet to keep your blood sugar levels in target. Stay away from sweets, candies, pastries, soft drinks, fruit punches and desserts. Because starches also provide a lot of glucose and can contribute significantly to elevating your glycemia, choose only starches that are minimally processed, rich in fiber and that have a low glycemic index value. For example, sweet potatoes, nonstarchy vegetables, fruits, quinoa, legumes, whole grain pasta and whole grain sourdough bread are better options to control your glycemia compared to white potatoes, bagels, white and whole wheat bread, buns, breakfast cereals and baked goods.
References
- Harvard School of Public Health; Carbohydrates: Good Carbs Guide the Way; 2011
- Cleveland Clinic; Carbohydrates and Blood Sugar Control for People with Diabetes; 2011
- USDA National Nutrient Database: Nutrient Data Laboratory
- "American Journal of Clinical Nutrition"; International Table of Glycemic Index and Glycemic Load Values; Kaye Foster-Powell, et al.; 2002
- Elmhurst College Chembook;Glucose; 2003
