Unit 5
The Carbohydrates: Sugar, Starch, and Fibre

Carbohydrates are the most abundant and readily available nutrient in foods. Some consumers attempt to restrict carbohydrate intakes because they believe carbohydrates are high in calories. Meanwhile, nutrition and health professionals consistently encourage higher carbohydrate intakes.

In this unit, we examine the classification of carbohydrates and give examples of food sources of each type. We review the processes of digestion and absorption of carbohydrates, and discuss the problem of lactose intolerance. We then discuss the functions of carbohydrates, the health effects of dietary fibre, and the regulation of blood glucose. Finally, we look at trends in carbohydrate consumption and the Canadian recommendations for carbohydrate intake.

Objectives

After completing this unit, you should be able to

1. discuss the classification systems for carbohydrate and fibre.
2. describe how carbohydrates are chemically digested.
3. explain what is meant by lactose intolerance and recommend suitable remedies for this health problem.
4. discuss the six functions of carbohydrates.
5. explain the roles of hormones that regulate blood glucose levels.
6. identify major dietary sources of different monosaccharides, disaccharides, and polysaccharides, including viscous and nonviscous dietary fibre.
7. describe the actions of fibre in the body and at least five health benefits of ingesting adequate dietary fibre.
8. explain how ingesting fibre helps to prevent constipation, diverticulosis, hemorrhoids, and appendicitis.
9. discuss the Canadian recommendations for carbohydrate and fibre intake, and identify the types of foods that will help Canadians achieve the recommendations.