Chapter 7

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the primary role of dietary carbohydrates in the body?

To provide energy (correct)

To assist in digestion

To provide essential nutrients

To generate muscle mass

Which of the following examples specifically falls under complex carbohydrates?

Rice (correct)

Milk

Candy

Fruit

What is one reason carbohydrates may be incorrectly thought to contribute to weight gain?

They are the body's main fuel source

They are often consumed in large quantities (correct)

They are the only energy source available

They contain essential fatty acids

Which carbohydrate is considered the storage form of carbohydrates in the body?

Glycogen Signup and view all the answers

What should nutrition coaches understand about carbohydrates?

They optimize health and performance when consumed in specific quantities Signup and view all the answers

What are carbohydrates commonly referred to as?

Sugars and starches Signup and view all the answers

What is the role of dietary fiber classified as?

Digestive aid and health promoter Signup and view all the answers

Which of the following is NOT a function of carbohydrates?

Contributing to tissue repair Signup and view all the answers

Which type of carbohydrate consists of single sugar units?

Monosaccharides Signup and view all the answers

What are the three nutritionally important disaccharides for humans?

Sucrose, maltose, and lactose Signup and view all the answers

What distinguishes fructose from glucose and galactose at the molecular level?

Different orientation of elements Signup and view all the answers

Which type of carbohydrate contains chains of glucose longer than 10 units?

Polysaccharides Signup and view all the answers

Where is glycogen primarily stored in the human body?

Liver and muscle cells Signup and view all the answers

Which of the following foods typically contains added sugars?

Candy and sweetened beverages Signup and view all the answers

What is the primary difference between naturally occurring sugars and added sugars?

Naturally occurring sugars come with other nutrients Signup and view all the answers

What characterizes oligosaccharides in terms of sugar units?

3 to 10 sugar units Signup and view all the answers

How do monosaccharides and disaccharides differ from polysaccharides?

Polysaccharides consist of multiple sugar units Signup and view all the answers

Which of the following examples is a disaccharide?

Sucrose Signup and view all the answers

What is the main purpose of carbohydrates once they are absorbed into the body?

Serve as a source of fuel Signup and view all the answers

What defines a carbohydrate’s chemical composition?

Carbon, hydrogen, and oxygen Signup and view all the answers

Which of the following is an example of a polysaccharide?

Starch Signup and view all the answers

What is the primary form of sugar found in milk?

Lactose Signup and view all the answers

What is the main benefit of insoluble fiber for digestive health?

It adds bulk and draws water into the GI tract. Signup and view all the answers

What happens to nutrients in whole grains during refining processes?

Fiber and nutrients are largely lost. Signup and view all the answers

Which of the following is considered a health benefit of insoluble fiber?

Reduced risk of colon cancer Signup and view all the answers

What is functional fiber?

Fiber derived from isolated carbohydrates. Signup and view all the answers

What is the recommended daily intake of fiber for women in the U.S.?

25 grams Signup and view all the answers

Which of the following food sources is rich in soluble fiber?

Oatmeal Signup and view all the answers

What is the role of glycogen in the body?

It serves as the storage molecule of glucose in animals. Signup and view all the answers

Which process describes the formation of glycogen?

Glycogenesis Signup and view all the answers

What condition occurs when pockets of collected stool form in the walls of the digestive tract?

Diverticulosis Signup and view all the answers

Which nutrient is NOT part of the glycogen structure?

Fructose Signup and view all the answers

What is one potential health benefit of dietary fiber intake?

Improved bowel movement Signup and view all the answers

Which of the following fibers is typically recognized for promoting bowel regularity?

Insoluble fiber Signup and view all the answers

What is a significant consequence of inadequate fiber intake in the U.S. population?

Increased cardiovascular issues Signup and view all the answers

Why are whole grains considered healthier than refined grains?

They contain all parts of the kernel. Signup and view all the answers

What is the primary storage molecule of carbohydrates in animals?

Glycogen Signup and view all the answers

What process involves breaking down glycogen into glucose units?

Glycogenolysis Signup and view all the answers

Why can't muscle glycogen be released into circulation?

Muscle cells lack glucose 6-phosphatase Signup and view all the answers

How much glycogen can an average adult store?

2000 to 2500 kcal Signup and view all the answers

What role do carbohydrates primarily play in the body?

Providing energy Signup and view all the answers

What happens to excess carbohydrates after the body’s immediate energy needs are met?

Stored as glycogen Signup and view all the answers

Which organ is unique in its ability to release glucose into the bloodstream?

Liver Signup and view all the answers

What can the body do when carbohydrate intake is insufficient?

Produce ketones for energy Signup and view all the answers

What factor influences the amount of glycogen the body can store?

All of the above Signup and view all the answers

How many grams of glucose are present in a small adult's blood?

3 to 5 grams Signup and view all the answers

What compounds are triglycerides primarily composed of?

Glycerol and fatty acids Signup and view all the answers

What is a potential consequence of low carbohydrate availability in the body?

Fat metabolism shifts to ketone production Signup and view all the answers

What is the physiological outcome when adequate carbohydrates are consumed?

Spared muscle tissue from breakdown Signup and view all the answers

What initiates carbohydrate digestion in the mouth?

Salivary amylase Signup and view all the answers

What is the term for the mass of food that is swallowed after chewing?

Bolus Signup and view all the answers

Which section of the small intestine is primarily responsible for nutrient absorption?

Ileum Signup and view all the answers

What does the hepatic portal vein transport?

Nutrient-rich blood from the intestines Signup and view all the answers

What is the main function of the brush border in the small intestine?

To enhance digestion and absorption Signup and view all the answers

Which carbohydrate is mostly oxidized for energy after absorption?

Glucose Signup and view all the answers

What condition occurs when the small intestine reduces lactase production with age?

Lactase non-persistence Signup and view all the answers

What happens to lactose in individuals who are lactose intolerant?

It is digested by intestinal bacteria Signup and view all the answers

What role does sodium bicarbonate play in digestion?

It neutralizes stomach acid in the duodenum Signup and view all the answers

In which part of the small intestine does most carbohydrate digestion occur?

Jejunum Signup and view all the answers

What type of carbohydrates are broken down into monosaccharides during digestion?

Disaccharides and polysaccharides Signup and view all the answers

Which of the following correctly describes chyme?

It is a semi-fluid mass of partially digested food Signup and view all the answers

How do glucose and galactose differ from fructose during absorption?

They undergo a different absorption process Signup and view all the answers

Which type of amylase continues carbohydrate digestion after food leaves the stomach?

Pancreatic amylase Signup and view all the answers

What are oligosaccharides primarily produced by?

Intestinal bacteria from starches and sugars Signup and view all the answers

Which type of carbohydrate consists of long chains of glucose molecules?

Polysaccharides Signup and view all the answers

What is a significant benefit of soluble fiber?

Promotes feelings of fullness Signup and view all the answers

What effect does amylopectin have on blood sugar levels compared to amylose?

Causes a quicker and greater spike in blood sugar Signup and view all the answers

Which of the following is considered an insoluble fiber?

Cellulose Signup and view all the answers

Which carbohydrate is primarily responsible for producing energy in the body?

Sugars Signup and view all the answers

How does physical activity relate to insulin sensitivity?

It can enhance insulin receptor function Signup and view all the answers

Which carbohydrate type includes fructo-oligosaccharides (FOS)?

Oligosaccharides Signup and view all the answers

What is the primary role of soluble fibers in dietary contexts?

Bind to and eliminate cholesterol Signup and view all the answers

What type of sugar is derived from chicory root?

Inulin Signup and view all the answers

What happens to insulin receptors with elevated levels of insulin?

They can become desensitized Signup and view all the answers

Which of the following is a common source of galacto-oligosaccharides (GOS)?

Human breast milk Signup and view all the answers

Why can fiber not be digested by human digestive enzymes?

It has no open ends Signup and view all the answers

What percentage of digestible starches do amylopectin and amylose account for respectively?

80% and 20% Signup and view all the answers

Study Notes

Carbohydrate Structure & Function

Carbohydrates are the body’s primary fuel source and are categorized as sugars and starches, or simple and complex carbohydrates.
Monosaccharides: Single sugar units (glucose, fructose, galactose) that are the absorbable form of carbohydrates for the body.
Disaccharides: Pairs of sugar units (sucrose, maltose, lactose).
Polysaccharides: Long glucose chains (starches, fibers, glycogen).
Oligosaccharides: A small group of carbohydrates with 3 to 10 sugar units that are mostly indigestible.

Types of Carbohydrates

Natural sugars: Found in fruit and milk; are generally considered healthier options because foods containing them also include other nutrients.
Added sugars: Sugars that are not naturally occurring in food groups, such as syrups and caloric sweeteners found in candy and sweetened beverages.

Importance of Fiber

Soluble fiber: Dissolves in water to form a gel and aids in digestion, heart health, and glucose control.
Insoluble fiber: Does not dissolve in water and promotes regularity in the colon.
Functional fiber: Derived from isolated, indigestible carbohydrates and may provide some benefits of natural fiber; examples include polydextrose and inulin.

Polysaccharide Structures

Amylose: Straight-chain digestible form of starch containing glucose molecules.
Amylopectin: Branched-chain digestible form of starch containing glucose molecules.
Fiber: A block structure that is indigestible.

Glycogen: Glucose Storage

Glycogen: The storage molecule of glucose in animals. It has a highly branched structure that allows enzymes to break it down rapidly during glycogenolysis.

Glycemic Index & Insulin Sensitivity

Amylopectin digests faster than amylose, leading to a greater spike in blood sugar levels.
Insulin sensitivity is important for maintaining blood glucose levels and can be improved by managing sugar and carbohydrate intake and engaging in regular physical activity.### Glycogen and Its Functions
Glycogen is the storage form of carbohydrate in animals, primarily found in muscle and liver cells.
Glycogenolysis is the breakdown of glycogen into glucose units, providing energy.
Glycogenesis is the process of forming glycogen from glucose.
Muscle glycogen is not readily available for blood glucose maintenance due to the absence of glucose 6-phosphatase enzyme, unlike in liver cells.
Liver glycogen is essential for maintaining stable blood sugar levels.
Muscle glycogen primarily fuels muscular work.
Average muscle glycogen storage is around 15 grams per kilogram (6.8 g/lb) of muscle tissue.
Muscle mass contributes significantly to total glycogen stores, averaging between 250 to 600 grams (1,000 to 2,400 kcal) in adults.
Liver glycogen storage is approximately 50 grams per kilogram (22.7 g/lb.) of liver tissue, totaling about 75 to 125 grams (300 to 500 kcal) in adults.
Blood glucose stores are relatively small, ranging from 3 to 5 grams in smaller individuals to 10 to 15 grams in larger individuals.
An average adult stores around 2,000 to 2,500 kcal of glycogen, with endurance athletes potentially storing more than 3,000 kcal.

Carbohydrate Classifications

Carbohydrates are classified based on the number of sugar units they contain.
The body digests and absorbs carbohydrates as monosaccharides, the simplest form.
These monosaccharides are the building blocks for larger carbohydrate structures like starches and sugars.

Carbohydrate Roles In The Body

The primary role of dietary carbohydrates is to provide energy.
Excess carbohydrates are stored as glycogen in muscle and liver.
Liver glycogen helps regulate blood glucose and insulin metabolism, impacting diabetes and metabolic syndrome.
Further excess carbohydrates can be converted to triglycerides (fats).
Balanced glucose and insulin levels regulate other hormones like testosterone and thyroid hormones.
Carbohydrates are crucial for complete fat metabolism. Insufficient carbohydrates result in the production of ketones from incompletely metabolized fat fragments.
In low-carbohydrate states, the body can produce glucose from non-carbohydrate sources like amino acids through gluconeogenesis, primarily derived from muscle tissue.
Adequate carbohydrates spare muscle breakdown during energy demands.
Soluble and insoluble fibers offer numerous health benefits including weight loss, cholesterol reduction, improved digestion, and cancer prevention.

Carbohydrate Digestion and Absorption

Digestion begins in the mouth with salivary amylase, an enzyme from the salivary glands.
Chewing and saliva facilitate digestion by increasing surface area.
Bolus refers to the chewed food mass ready for swallowing.
In the stomach, food mixes with gastric juices and the high acidity continues digestion.
Chyme is the partially digested food mass passed from the stomach to the duodenum.
In the duodenum, sodium bicarbonate from the pancreas neutralizes the acidic chyme, allowing pancreatic amylase to continue digestion in the jejunum.
Further breakdown occurs in the jejunum, producing disaccharides and monosaccharides, which then move to the ileum for absorption.
Disaccharides are further broken down to monosaccharides within the brush border of the intestinal wall.
Villi and microvilli within the small intestine increase surface area for nutrient absorption.
Brush border cells release enzymes to digest disaccharides into monosaccharides.
Once absorbed, monosaccharides enter the hepatic portal vein for transport to the liver.
Glucose and galactose are absorbed faster than fructose.
Glucose is used directly for energy, while fructose is partially oxidized for energy (35-45%).
Lactose intolerance results from lactase deficiency or insufficiency, leading to undigested lactose, causing bloating, diarrhea, gas, nausea, and abdominal pain.
Lactose intolerance is often genetically inherited and can develop with age.
Individuals with lactose intolerance can avoid dairy, consume lactose-free products, or take lactase enzyme supplements.

Carbohydrate Fate After Absorption

After meeting immediate energy needs, surplus glucose and fructose replenish liver and muscle glycogen stores.
Glucose molecules form glycogen chains, while a portion of fructose is converted to glucose for glycogen synthesis.
Excess fructose is either oxidized or converted to lactate (30%) or triglycerides (fats).

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Test your knowledge on the various types of carbohydrates and their importance in nutrition. This quiz covers monosaccharides, disaccharides, polysaccharides, and recognizes the role of dietary fiber. Explore the differences between natural and added sugars and their impact on health.