Simple and Complex CHO

Question 1

Simple CHO

Answer 1

Disaccharides = sucrose, maltose, lactose
-breaks down into monosaccharides at villi in small intestine to allow for absorption.
Monosaccharides = glucose, fructose, galactose

Question 2

Complex CHO

Answer 2

Known as polysaccharides.
Starch = chains of glucose; plant storage form of glucose.
-glucose chains in plants
-amylopectin and amylose
Glycogen = chains of glucose; human storage form of glucose
-glucose chains in animals
Fibres = soluble and insoluble
-humans can’t digest cellulose

Question 3

CHO on Food Labels

Answer 3

Lists simple sugars (mono and disaccharides) and complex CHO (fibre), but does not list polysaccharides.

Question 4

Fibre Terminology

Answer 4

Total fibre (non-digestible plant parts)
-soluble fibre and insoluble fibre
-functional fibre = fibre extracted/manufactured for health benefits
-cellulose, guar gum, pectin, psyllium, inulin

Question 5

Soluble Fibre

Answer 5

Dietary and functional fibres that absorb water.
Sources include fruit pectins, oatmeal, oatbran, legumes.
Actions = absorb water to form thick solutions in GI tract.
Benefits = traps glucose and slows down glucose absorption, and may reduce blood cholesterol.
Soluble fibre foods include citrus fruit, apples, berries, oats, legumes.

Question 6

Insoluble Fibre

Answer 6

Fibre with lower water-holding capacity.
Sources include vegetables, grains/cereals (lignans, cellulose).
Actions = bind/absorb micronutrients and increase fecal bulk.
-does not swell with water, but will bind with other nutrients.
Benefits = speed up GI tract (increase speed that food moves through) and increase fecal bulk.
Insoluble fibre foods include grains (wheat, rye, brown rice), veggies, legumes, fruits, and berries.

Question 7

Fibre Summary

Answer 7

Soluble = soft and sticky parts of plants
-absorbs water/slows absorption of glucose and traps cholesterol
Insoluble = roughage ‘tough matter’
-adds bulk to stool, reduces GI transit time
-relieves constipation

Question 8

Prebiotics

Answer 8

Dietary material gut bacteria can feed on.
Fibre is possible = gut bacteria can ferment some of it.

Question 9

Probiotics

Answer 9

Cultured foods/drinks contain bacteria.
Fermented foods (including homemade pickles).
Yogurts (probiotic).

Question 10

Postbiotics

Answer 10

Healthy by-products produced by gut bacteria from pre/probiotics (K & B vitamins)

Question 11

Soluble fibre can be classified as…

Answer 11

Fermentable fibre and non-fermentable fibre.
Insoluble fibre is poorly fermented.

Question 12

Fermentable Fibre

Answer 12

Metabolized by gut bacteria to form short-chain fatty acids and gases.
They do not have a laxative effect because, when fermented, they lose water holding capacity.
Includes prebiotics.

Question 13

Non-fermentable Fibres

Answer 13

Retain their water-holding capacity because they are resistant to fermentation.
They exert a stool softening effect.
Support bowl movements.

Question 14

CHO Digestion

Answer 14

Mouth = salivary amylase
-once reach the stomach, salivary amylase stops working due to pH dropping.
Small Intestine = pancreatic amylase
Microvilli (brush border in the small intestine) = sucrase, maltase, lactase
-breakdown disaccharides down to monosaccharides

Question 15

CHO Absorption

Answer 15

Only monosaccharides are absorbed
-glucose, galactose, and fructose only
Glucose and galactose absorbed by secondary active and active transport (sodium/potassium ATPase pump).
Fructose absorbed by facilitated diffusion.
-absorbed more slowly than glucose or galactose.

Question 16

CHO Transportation

Answer 16

Glucose, fructose, and galactose transported to liver via the hepatic portal system

Question 17

CHO and the Liver

Answer 17

Liver converts some fructose and most galactose to glucose.
-most everything gets converted to glucose.
Liver decides where carbohydrate goes to in the body (ie. quarterback of glucose distribution).
-Energy needed = glucose released into bloodstream
-no energy needed = glucose stored as glycogen in liver (70g) or muscles (120g)
-once the muscle stores are full, will be stored as fat in adipose tissue

Question 18

CHO Fate

Answer 18

Used for energy.
Stored as glycogen.
Stored as fat in adipose tissue
-~70% efficiency (will lose energy contained in glucose when it is converted to fat).

Question 19

CHO and Physical Activity

Answer 19

Athletes use and store more CHO.
Glucose utilization depends on intensity and duration.
As exercise intensity increase, glucose utilization goes up.

Question 20

What is the glycemic index?

Answer 20

A measure of how quickly glucose enters the bloodstream.
Rating of the potential of food to raise blood glucose levels.
-higher the number, the quicker glucose can get into bloodstream and increase blood glucose.

Question 21

What effects of GI of food?

Answer 21

Type of CHO
Food Preparation
-ie. cooking = pre-digest foods so less work needed to break it down
Fat content
-ie. slows gastric emptying = mutes GI of food when eaten with fat
Fibre content
-clothing food = mute GI, don’t absorb as much glucose
Combining foods

Question 22

Using the GI

Answer 22

Informs diabetes.
Glycemic load = grams of CHO x GI
Health implications of lower GI meals
-low GI meals have increased fibre
-low GI meals associated with increased HDLs (good cholesterol)

Question 23

How much CHO do we eat?

Answer 23

~50% of total caloric intake is CHO.
~25% is from simple sugars
-tooth decay, unhealthy blood lipids, and contributes to obesity

Question 24

Metabolic Differences Between Glucose and Fructose

Answer 24

Glucose
-stored in liver as glycogen
-used for energy
-stored in muscles
-a little bit becomes fat
Fructose
-little stored as glycogen
-create hepatic lipid droplets
-triggers insulin resistance
-more becomes fatty acids
-disrupts leptin (satiety)