Introduction
E ʻai i ka mea i loaʻa
What you have, eat
Learning Objectives
By the end of this chapter, you will be able to:
- Describe the different types of simple and complex carbohydrates
- Describe the process of carbohydrate digestion and absorption
- Describe the functions of carbohydrates in the body
- Describe the body’s carbohydrate needs and how personal choices can lead to health benefits or consequences
Throughout history, carbohydrates have and continue to be a major source of people’s diets worldwide. In ancient Hawai‘i the Hawaiians obtained the majority of their calories from carbohydrate rich plants like the ‘uala (sweet potato), ulu (breadfruit) and kalo (taro). For example, mashed kalo or poi was a staple to meals for Hawaiians. Research suggests that almost 78 percent of the diet was made up of these fiber rich carbohydrate foods.[1]
Carbohydrates are the perfect nutrient to meet your body’s nutritional needs. They nourish your brain and nervous system, provide energy to all of your cells when within proper caloric limits, and help keep your body fit and lean. Specifically, digestible carbohydrates provide bulk in foods, vitamins, and minerals, while indigestible carbohydrates provide a good amount of fiber with a host of other health benefits.
Plants synthesize the fast-releasing carbohydrate, glucose, from carbon dioxide in the air and water, and by harnessing the sun’s energy. Recall that plants convert the energy in sunlight to chemical energy in the molecule, glucose. Plants use glucose to make other larger, more slow-releasing carbohydrates. When we eat plants we harvest the energy of glucose to support life’s processes.
Figure 4.1 Carbohydrate Classification Scheme
Carbohydrates are a group of organic compounds containing a ratio of one carbon atom to two hydrogen atoms to one oxygen atom. Basically, they are hydrated carbons. The word “carbo” means carbon and “hydrate” means water. Glucose, the most abundant carbohydrate in the human body, has six carbon atoms, twelve hydrogen atoms, and six oxygen atoms. The chemical formula for glucose is written as C6H12O6. Synonymous with the term carbohydrate is the Greek word “saccharide,” which means sugar. The simplest unit of a carbohydrate is a monosaccharide. Carbohydrates are broadly classified into two subgroups, simple (“fast-releasing”) and complex (“slow-releasing”). Simple carbohydrates are further grouped into the monosaccharides and disaccharides. Complex carbohydrates are long chains of monosaccharides.
Simple/Fast-Releasing Carbohydrates
Simple carbohydrates are also known more simply as “sugars” and are grouped as either monosaccharides or disaccharides. Monosaccharides include glucose, fructose, and galactose, and the disaccharides include lactose, maltose, and sucrose.
Simple carbohydrates stimulate the sweetness taste sensation, which is the most sensitive of all taste sensations. Even extremely low concentrations of sugars in foods will stimulate the sweetness