EPE 155: Macronutrients - Carbohydrates

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Questions and Answers

What distinguishes whole-wheat flour from refined flours?

It is made from whole wheat kernels. (correct)

It undergoes a bleaching process.

It contains added sugars and preservatives.

It is lower in fiber content.

How does the body primarily utilize glucose after ingestion?

Glucose is excreted if not needed immediately.

Glucose is utilized directly for cellular energy through glycolysis. (correct)

Glucose is immediately converted to fat for storage.

Glucose must first be stored as fiber before use.

What is the primary role of glycogen in the body?

To maintain blood glucose levels and supply energy. (correct)

To act as a precursor for amino acids.

To serve as a primary source of dietary fiber.

To enhance the flavor of carbohydrates.

Which statement correctly describes the regulation of blood glucose levels?

The hypothalamus plays a role in monitoring blood glucose levels. Signup and view all the answers

What is one reason the body can manage glucose levels effectively?

The liver stores and releases glucose in response to hormonal signals. Signup and view all the answers

What is a primary characteristic that differentiates fibre from other carbohydrates?

Fibre cannot be digested by humans. Signup and view all the answers

Which of the following statements about soluble and insoluble fibre is correct?

Soluble fibre absorbs water and can help thicken food. Signup and view all the answers

Which type of carbohydrate is classified as a monosaccharide or disaccharide?

Simple carbohydrates Signup and view all the answers

Why do digestive microbes ferment fibre, and what is produced as a result?

To generate short-chain fatty acids. Signup and view all the answers

What role does fibre play in digestive health according to recommended daily intake guidelines?

It aids in modulating blood glucose concentrations. Signup and view all the answers

Which of the following is NOT a health benefit associated with dietary fibre?

Increased absorption of glucose. Signup and view all the answers

What distinguishes complex carbohydrates from simple carbohydrates?

Complex carbohydrates include polysaccharides such as starch and glycogen. Signup and view all the answers

What is the recommended daily intake of fibre for men aged 19-50?

38g Signup and view all the answers

What distinguishes fiber from other carbohydrates in terms of digestibility?

Fiber cannot be broken down by digestive enzymes. Signup and view all the answers

Which type of carbohydrate primarily serves as an energy source, unlike fiber?

Starch Signup and view all the answers

Which of these carbohydrates is classified as soluble fiber?

Inulin Signup and view all the answers

What is a primary health benefit of fiber that differs from other types of carbohydrates?

Aids in weight management and digestion. Signup and view all the answers

Which carbohydrate type is least likely to be fermented by gut bacteria?

Insoluble fiber Signup and view all the answers

Which type of carbohydrate has a lower glycemic index and is beneficial for blood sugar control?

Fiber Signup and view all the answers

Which of the following carbohydrates can lead to increased fat deposits when consumed in excess?

Starch Signup and view all the answers

What characteristic makes fiber a unique carbohydrate compared to sugars and starches?

Helps regulate cholesterol levels. Signup and view all the answers

In what way does soluble fiber differ from insoluble fiber in its effect on digestion?

Soluble fiber helps to lower blood sugar levels. Signup and view all the answers

What is a primary role of soluble fiber in digestive health?

Absorbs water and aids bowel movements Signup and view all the answers

Which component of whole grains is primarily removed in the refining process?

The bran and germ Signup and view all the answers

Which of the following statements correctly distinguishes fibers from other carbohydrates?

Fibers assist in regulating digestive health Signup and view all the answers

What is a potential negative effect of consuming excessive fiber?

Development of digestive discomfort Signup and view all the answers

How can the effects of anti-nutrients found in certain foods primarily be minimized?

Through proper cooking methods Signup and view all the answers

What function does the germ serve in a whole grain?

It can germinate into a new plant Signup and view all the answers

What can result from inadequate hydration when consuming soluble fiber?

Risk of constipation Signup and view all the answers

Which of the following describes the endosperm of a grain?

It consists mainly of starch and protein Signup and view all the answers

In terms of nutrient absorption, what is a significant role of anti-nutrients?

They bind to minerals, reducing their absorption Signup and view all the answers

Study Notes

Introduction to Nutrition: Concepts & Controversies - Macronutrients - Carbohydrate

Carbohydrate is a macronutrient.
The course is EPE 155, Introduction to Nutrition: Concepts & Controversies.
The presenter is Dr. Kimberly McQueen, BSc ND, from the University of Victoria, School of Exercise Science, Physical and Health Education.
Email: [email protected]
Learning goals include describing major carbohydrate types and food sources, roles of carbohydrates in the body, key differences between fiber and other carbohydrates, how carbohydrates are broken down and absorbed, and the body's management of glucose.

Learning Goals

Describe major carbohydrate types and identify foods that are sources.
Describe the role of carbohydrates in the body.
Identify key differences between fiber and other carbohydrates.
Explain carbohydrate breakdown and absorption.
Discuss the body's management of glucose.

Food Sources

Vegetables
Fruits
Whole Grains

Carbohydrate Types

Simple Carbohydrates
- 6 molecules in this group
- Chemical names end in -ose
- Classified as monosaccharides and disaccharides
Complex Carbohydrates
- Includes glycogen, starch, and fiber
- Classified as polysaccharides

Simple Carbohydrates (aka Simple Sugars)

Monosaccharides (e.g., fructose, glucose, galactose) join to form disaccharides (e.g., sucrose, maltose, lactose).
Sucrose (fructose-glucose) is table sugar.
Glucose is a major source of energy.
Milk is a major source of galactose.

Complex Carbohydrates (Polysaccharides)

How glucose molecules join to form polysaccharides, diagrams showing starch (unbranched and branched), glycogen, and cellulose (fiber).
Starch and glycogen are digestible.
Cellulose is fiber, not digestible by humans but fermented by gut microbes.

Key Differences Between Fiber and Other Carbohydrates

Human digestion cannot break down fiber's bonds; minimal energy.
However, gut microbes can ferment fiber, producing short-chain fatty acids (SCFA) like butyrate, propionate, and acetate that fuel digestive cells and contribute to digestive health.
Two main categories of fiber: soluble (absorbs water, thickens) and insoluble (does not absorb water, maintains shape)
Examples of soluble fiber: barley, oats, fruits, legumes etc.
Examples of insoluble fiber: brown rice, fruits, vegetables, and legumes etc.

Health Effects of Fibers

Viscous, soluble fibers reduce blood cholesterol and slow glucose absorption.
Nonviscous, insoluble fibers increase fecal weight and speed fecal passage.

Fibre Composition of Common Foods

Tables showing the fiber content of various foods (grains, fruit, legumes, vegetables).

Known Health Benefits of Fiber

Heart and metabolic health; reduces risk of heart disease, promotes normal cholesterol and blood glucose levels.
Digestive health, supports gut microbiota; promotes regular bowel movements, reduces constipation, diverticulosis, appendicitis, and colon cancer.
Weight management; enhances satiety, regulates appetite, prevents overeating.

Cautions About Fiber

Too much fiber can cause digestive issues like bloating, gas, cramping, or diarrhea.
Some fiber components (e.g., phytates, oxalates) in foods can reduce mineral absorption (e.g., calcium, iron). Proper food preparation techniques can minimize this effect.
Soluble fiber absorbs water, potential for dehydration risk if not properly hydrated.

One-Way Fiber in Food May Lower Cholesterol in the Blood

High-fiber diet; more cholesterol (in bile) is carried out of the body.
Low-fiber diet; more cholesterol (from bile) is reabsorbed into the bloodstream.

Whole Grains

Diagram shows a wheat kernel highlighting its parts (germ, endosperm, bran, husk).
Refining removes husk, bran, and germ, leaving endosperm.

Terms That Describe Grain Foods

Definitions for terms like bran, brown bread, endosperm, enriched, fortified, germ, husk, refined, stone ground, unbleached flour, wheat flour, white flour, whole grain, and whole-wheat flour are provided.

Blood Glucose Regulation

Hypothalamus monitors blood glucose levels and signals the pancreas to respond.
Pancreas response to increased blood glucose; secretes insulin to enable glucose uptake and glycogen storage in liver and muscles.
Pancreas response to decreased blood glucose; secretes glucagon to release glycogen and increase glucose.

Glucose Storage

Liver, Muscle, and Brain cells use incoming glucose to build glycogen.
Muscles conserve glycogen for their own use and often store most of the body's glycogen.
Liver is generous with its glycogen, releasing glucose as needed, triggered by glucagon release from the pancreas.
Liver stores enough glycogen for about 3-6 hours.
Brain stores a small amount of glycogen for about 1-2 hours.

Glucose

Best known for its role in providing energy to most cells.
Body handles glucose judiciously, maintaining an internal supply and tightly controlling blood glucose concentrations.

Digestion and Absorption of Carbohydrates

Steps in carbohydrate digestion and absorption, including in the mouth and small intestine.
Enzymes in the digestive system break down complex carbohydrates into monosaccharides (e.g., glucose, fructose) which are absorbed into the bloodstream.
The liver converts galactose and fructose into glucose.
Monosaccharides enter capillaries and are delivered to the liver via the portal vein.

Below Minimum Daily Intake of Carbohydrate to Maintain Health

Minimum daily carbohydrate intake is 130 grams digestible carbohydrate.
Below this minimum, the body converts to protein to make carbohydrate, conserving protein for its essential functions,
Changes fat metabolism (fat fragments combining create ketone bodies) and results in ketosis.

Once Muscle and Liver Glycogen Stores are Saturated

If there is still plenty of glucose available, the body prioritizes burning glucose over fat for energy.
Excess fat remains in circulation and is stored in adipose tissue.
Liver converts excess glucose into fat and sends it to fat cells for storage.
If glucose levels remain high, fat cells convert glucose into fat, requiring multiple energy-intensive enzymatic steps.

Glycemic Index and Glycemic Load

Glycemic Index (GI) measures how quickly a food raises blood sugar compared to glucose.
Glycemic Load (GL) factors in both GI and carbohydrate content to measure blood sugar impact.
Managing GI/GL can support diabetes control and reduce insulin needs.

Prevalence of Diabetes

Diabetes is one of the top 10 causes of death worldwide, a significant concern.
An estimated 2.4 million Canadians were living with diabetes as of 2016.
Types of diabetes: Type 1 (autoimmune, insulin-dependent); Type 2 (lifestyle-related, managed with diet/exercise); Gestational (pregnancy-related).
A proposed Type 3 diabetes link to insulin resistance and dementia.

Where Do We Find Carbohydrates?

Recommendations for whole-grain, low-fat, and low-sugar food choices that maximize nutrient density.
Examples of food sources and their carbohydrate content (vegetables, fruits, non-meat protein foods, milk, sugary drinks.)

Sugar

Definitions/descriptions for various types of sugars and terms like agave syrup, brown sugar, concentrated fruit juice, confectioner's sugar, corn syrup, dextrose, (HFCS) high-fructose corn syrup, evaporated cane juice, free sugars, fructose, glucose, granulated sugar, honey, invert sugar, lactose, levulose, maple sugar, molasses, raw sugar, sucrose, and turbinado sugar.
Understanding of the differences between naturally occurring and added sugars and their effects.

Carbohydrate Targets

Acceptable Macronutrient Distribution Range (AMDR) for carbohydrates, recommended intake range.
Dietary Reference Intake (DRI) minimum carbohydrate intake.
Recommended intake for women/men based on age with different DRIs.
World Health Organization recommendations for fiber and sugar intake.

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Description

This quiz explores the essential macronutrient carbohydrate, focusing on its types, food sources, and role in the body. You'll learn about the breakdown and absorption of carbohydrates, as well as the differences between fiber and other carbohydrates. Perfect for students in EPE 155: Introduction to Nutrition.