Chapter 4: Carbohydrates Flashcards
What are carbohydrates? What is their primary purpose?
Carbohydrates are macronutrients.
Primary purpose is to provide energy for the body. They are considered to be the primary fuel source for activity.
We generally consume more of this macronutrient in grams than we do of any of the others.
What is the chemical composition of glucose?
Glucose is the main form of sugar that we like to use in the body.
It’s a simple sugar made up of 6 carbons, 12 hydrogens, and 6 oxygens. With 1 molecule of glucose, we can get 30 molecules of ADPT through glycolysis.
What are the two types of simple carbohydrates? Give some examples of the foods containing them.
monosaccharides and disaccharides
Monosaccharides consist of only one sugar unit. They are the simplest form of sugar and they are going to make up the more complex carbohydrates. Some examples of monosaccharides are glucose, galactose, mannos, and fructose.
Disaccharides consist of two sugar units. Some examples are sucrose, which is made up of one molecule each of glucose and fructose; maltose, made of two glucose molecules; and lactose, made of one molecule glucose and one molecule of galactose. The main monosaccharides in our foods are glucose and fructose.
What are complex carbs? What are the forms of complex carbs?
We have two main forms of complex carbohydrates. .
The first is the oligosaccharides, which are complex carbs with 3 – 10 subunits. Some common examples will be raffinose and stachyose.
The last form of carbohydrates are the polysaccharides. These are complex carbs with more than 10 monosaccharide subunits linked together. Starch is a main dietary complex carb, and this is made up of amylopectin and amylose.
What type of macronutrient is fiber? Know the two categories we put Fiber in.
fiber is a special complex carb. it can be digested or absorbed
Fiber is a special form of complex carb that does not actually get digested or get absorbed by the small intestine. It is still quite important to have in our diets. We also know Fiber as terms like roughage or non-starchy polysaccharides. Some common examples are with things like cellulose, hemicellulose, pectin, fructans, beta-glucans, and a variety of gums, mucilage, and algal polysaccharides.
Discuss Fiber and its various forms. What sources exist for these forms of Fiber?
There are two main forms of Fiber: Soluble and Insoluble.
Soluble Fiber dissolves in the stomach fluids and then form a gel-like substance. It is then later broken down by bacteria within the large intestine and then provides some very small form of energy for the body. Somewhere around 2 calories per gram are provided. Soluble Fiber may interfere with the digestion of dietary fat and cholesterol. This helps with the lowering of what we consider to be the bad cholesterol, LDLs.
Insoluble Fiber is a fiber that will not dissolve in water, and it basically passes through the entirety of the GI tract together and is no source of calories. This is used to provide bulk for the formation of stool and speed up the movement of foods and waste products through the digestive system.
What is the role of glycogen in the body?
Glycogen is seen as the main unit of storage for units of glucose in the body. We use these stores later as we break them down again from glycogen to the glucose molecules. It is made of just chains of glucose molecules, and the body has a limit to how much may be stored. This limit is usually around 1,800 – 2,600 calories. The body is constantly storing and releasing these molecules.
Where do we store glycogen in the body?
We store our glycogen in all of our cells in some small amount, but the main sources are going to be where they are needed the most: the liver and the muscle cells. The liver storage of glycogen is used to quickly change the blood sugar levels and it is the main source of energy for the brain. The muscle stores are for during times of activity.
Explain the steps in the process of digestion for carbohydrates.
Carbohydrate digestion is considered to be the quickest of the macronutrients. But this also depends on the form that the carbohydrates are coming in. The digestion begins within the mouth. Here we chew the food, and it breaks down the food mechanically. Along with this, the saliva lubricates the mass of chewed food and releasees the enzyme known as amylase, which works to easily break the bonds holding the carbs bigger than monosaccharides. This works to get more carbs in the more easily handled monosaccharides form. Around 5 percent of the starches in the mouth are actually broken down, the rest move on to other parts. From the mouth and stomach, we move to the small intestine, where the chyme enters, and the pancreas introduces pancreatic juice. This is used to chop the chains into smaller parts to more quickly deal with. Some enzymes come in like the lactase, maltase, and sucrase, and these works to break down specific carbohydrates to their simpler forms like glucose and fructose. The
carbohydrates are then absorbed into the bloodstream so that they may be used in the cells around the body for their actual purpose.
How can we use the glycemic index to rank our foods?
The Glycemic Index is a ranking system that goes on a scale of 0 – 100 and tells how much your blood sugar levels change after eating food. Proteins and fats are not scored here, since they are not the main source of blood glucose. Foods that are high in the glycemic index will be more quickly digested, absorbed, and metabolized by the body. A diet with many high GI foods may lead to problems in overconsumption and then eventually to gaining weight over time.
What factors affect the Glycemic Index of a food?
The Glycemic Index of a food will depend on several factors like:
a. The type of sugar in the food
b. The structure of the starch
c. How the food was processed
d. The way the food was prepared
e. The ripeness of a fruit
The biggest difference between types of carbs consumed is…
…in how they are digested and used. The more complex the bonds between the units of different sugar types, the slower the digestion and absorption.
What is lactose intolerance the result of?
Lactose intolerance results from insufficient lactase production. (Lactase is the breakdown of lactose into galactose and glucose).
Undigested lactose makes its way to the large intestine, where bacteria break it down. This process creates gas, diarrhea, bloating, and abdominal cramps.
Difference bw glycemic index and glycemic load
The GI of a food provides an estimate of how a food raises blood sugar levels but does not consider portions or quantity.
The glycemic load (GL) is a calculation that considers both GI value (carbohydrate quality) and portion size (carbohydrate quantity)
How do you calculate glycemic load?
(GI value of the food × the quantity of carbohydrates of the serving in grams) / 100
For example, for a food with a GI of 54 and an available 20 grams of carbohydrate per serving, the GL value is (54 × 20) / 100 = 10.8
