(CH
2
O) n
• Simple carbohydrates
–Monosaccharides (single sugars)
–Disaccharides (double sugars)
• Complex carbohydrates
– Polysaccharides (many sugars)
Copyright 2005 Wadsworth Group, a division of Thomson Learning

Monosaccharides
(C
6
H
12
O
6)
Glucose
Fructose
Galactose
Copyright 2005 Wadsworth Group, a division of Thomson Learning

Glucose – dextrose or blood sugar
1. Primary fuel for the body
2. Found in all disaccharides & polysaccharides

Fructose – fruit sugar
1. Found in fruit, honey, syrup
2. Converts to glucose in the body

Galactose – part of lactose
1. Found in milk
2. Converts to glucose in the body

Disaccharides
Maltose
Sucrose
Lactose
Copyright 2005 Wadsworth Group, a division of Thomson Learning

Sucrose – table sugar
1. Glucose + Fructose
2. Refined from sugar beets & cane

Lactose – milk sugar
1. Glucose + Galactose
2. Lactose intolerance – missing digestive enzyme needed to split into two monodisaccharide parts to absorb it

Maltose – malt sugar
1. Glucose + Glucose
2. Found in germinating seeds & used in fermentation to produce malted beverages (beer, whiskey)

Polysaccharides
Glycogen
Starches
Fibers
Copyright 2005 Wadsworth Group, a division of Thomson Learning

Glycogen – long chains of glucose found in animals
1. Stored in liver & muscles
2. Helps maintain blood glucose and important source of “quick energy”, esp. during exercise
(lasts only about 12 hrs)

Starch – long chains of glucose found in plants
1. Cereal grains (wheat, rice, corn, etc.), legumes (beans & peas), and root vegetables
(potatoes, yams)

Fiber – mostly indigestible CHO; gums, mucilages, lignin
1. Component of plant cell walls
2. Classified according to solubility in water
3. Abundant in whole grains, legumes, fruits and vegetables

Insoluble – nonviscous; cellulose, lignins
Soluble – viscous & fermentable; pectins, gums, mucilages

• Mouth
–Salivary amylase
• Stomach
–Fibers and satiety
• Small Intestine
-Maltase, sucrase, lactase

• Pancreas
–Pancreatic amylase
• Large Intestine
-Fermentation of viscous fibers
 Water, gas, short-chain fatty acid production

Carbohydrate Digestion in the GI Tract

Glucose in the Body
• Used for energy – fuels most of the body’s cells
• Stored as glycogen – 1/3 in the liver and
2/3 in muscles
• Made from protein – gluconeogenesis
• Converted to fat – when in excess of body’s needs

Constancy of Blood Glucose
• Regulating hormones – maintain glucose homeostasis
1. Insulin – moves glucose from the blood into cells
2. Glucagon – signals the liver to release glucose into the blood
3. Epinephrine – released when emergency fuel needed

Maintaining Blood Glucose Homeostasis

• Diabetes
–Type 1 diabetes
•Failure of insulin production
–Type 2 diabetes
•Obesity
• Hypoglycemia
–Rare in healthy people
• Glycemic response
–Glycemic index

Glycemic Index

• Sugar in excess
1. Contains no nutrients and may contribute to malnutrition
2. Causes dental caries (tooth decay)
3. Does not cause, but can contribute to: obesity, diabetes, heart disease, & behavorial problems

Accusations Against Sugars
• Sugar causes obesity
• Sugar causes heart disease

Accusations Against Sugars
• Sugar causes misbehavior in children and criminal behavior in adults
• Sugar causes cravings and addictions
–serotonin

• DRI
–No more than 25% of total daily energy intake
-Limit added sugars to <10% of total energy intake
Copyright 2005 Wadsworth Group, a division of Thomson Learning

• Complex carbohydrates & fiber may reduce the risk of:
-Heart disease
-Diabetes
-GI health
-Cancer
-Weight
Management

How?
• Diets high in complex CHO tend to be:
1. Lower in fat and calories
2. Higher in fiber, vitamins, & minerals

Soluble Fibers
• Lower blood cholesterol by binding dietary cholesterol so less absorbed
• Slow glucose absorption
• Slow transit of food through upper GI tract
• Holds moisture in stools, softening them
• Lower risk of heart disease
• Lower risk of diabetes

• Gums & mucilages, pectins, psyllium
• Sources
–Whole-grains, fruits, legumes, seeds and husks, vegetables
–Extracted and used as food additives

Insoluble Fibers
• Increase fecal weight - helps form soft, bulky stools which improves
G.I. motility & reduces risk of constipation, hemorrhoids, diverticulosis & colon cancer
• Speed fecal passage through colon
• Provide bulk and feelings of fullness
(satiety)

• Cellulose, lignins, hemiculloses
• Sources
–Brown rice, fruits, legumes, seeds, vegetables, wheat bran, whole grains
–Extracted and used as food additives

Recommended Intakes of Carbohydrates & Fibers
• RDA for carbohydrate
–130 g/day
–45% - 65% total daily energy intake with emphasis on complex
-Daily Value: 300 g/day
• Fiber
–Daily Value: 25 g/day
–AI: 14 g/1000 kcal/day

Dietary Recommendations
Example:
If 2000 kcal diet, then:
1100-1200 kcals as CHO
(275-300 grams) with < 200 kcals as “added sugar”
(50 grams)
One 12 oz. soft drink has 36-40 gms sugar
0ne tsp. sugar weighs 4 gms = 9-10 tsps!

Two Categories
1. Sugar Alcohols – mannitol, sorbitol, xylitol
2. Artificial sweeteners – sugar substitutes
(calorie-free); in moderation, useful for blood sugar & weight control

Sugar Alcohols
1. CHOs that provide less energy than sucrose (2-3 kcals/gm) because not completely absorbed
2. May cause gas, abdominal discomfort, diarrhea
3. Less cariogenic than sugar

Artificial Sweeteners
1. Saccharin = “Sweet ‘N Low” or
“Sugar Twin”
2. Aspartame = “Equal” or “Nutrasweet” must avoid if have phenylketonuria
3. AcesulfameK = “Sunette” or “Sweet
One”
4. Sucralose = “Splenda”

Alternatives to Sugar
• Acceptable Daily Intake (ADI)
• Artificial sweeteners and weight control
• Saccharine and cancer
• Aspartame and PKU

Sugar Alternatives on Food Labels

Alcoholic Beverages
• Rule of thumb to figure calories per ounce for wines and distilled spirits
Wine : Multiply the “percent of alcohol by volume” by two to obtain calories/ounce
Example: Zinfandel is 12.5% alcohol by volume, 12.5 X 2 = 25 calories/ounce
Distilled Spirits (hard liquor): Proof minus 15 to obtain calories per ounce
Example: 80 proof whiskey – 15 = 65 calories per ounce