Transcript Simple sugars - CindiLamb.com

Judith E. Brown
www.cengage.com/nutrition/brown
Useful Facts about Sugars,
Starches, and Fiber
Unit 12
Prof. Albia Dugger • Miami-Dade College
The Carbohydrates
• Carbohydrates
• Chemical substances in foods that consist of a
simple sugar molecule or multiples of them in
various forms
• Primary ingredient of staple foods (pasta, rice,
cassava, beans, bread)
Three Types of Carbohydrates
1. Simple sugars
2. Complex carbohydrates (starches)
3. Total fiber
Carbohydrate Sources
• Simple sugars (left), starch and fiber (right)
Carbohydrate Functions
• Major source of energy
• Recommended intake 45-65% of total calories
• Simple sugars and complex carbohydrates supply
4 calories/gram
• Dietary fiber indirectly supplies 2 calories/gram
(when digested by bacteria in colon)
• Other functions in immune and reproductive
systems, blood clotting, DNA
Alcohol
• Alcohol (ethanol) and alcohol sugars have
similar structures
Simple Sugar Facts
• Simple sugars (sugars)
• Carbohydrates that consist of a glucose, fructose,
or galactose molecule, or a combination of
glucose and either fructose or galactose
• Also includes high-fructose corn syrup and
alcohol sugars
Two Types of Simple Sugar
• Monosaccharides
• Consist of one sugar molecule
• Glucose, fructose, galactose
• Disaccharides
• Consist of two monosaccharides linked together
• Sucrose, maltose, lactose
• Broken into monosaccharides by digestion
Disaccharides
Energy Production
• Glucose is the only simple sugar the body can
use to form energy
• Fructose, galactose are converted to glucose
• Excess glucose is converted to fat and glycogen
• Body produces glucose by breaking down
glycogen, amino acids, glycerol from fats
• Cells in brain, blood, and kidneys require a
constant supply of energy from glucose
Glycogen
• Glycogen
• Storage form of glucose
• Complex carbohydrate
• Long chains of glucose
molecules
• Produced only by
animals
• Stored in liver and
muscles
Body’s Sources of Glucose
Simple Sugar Intake
• In US, total simple
sugar intake averages
23% of total calories
• 17% of total calories
from added sugars
• Sucrose
• High-fructose corn syrup
Simple Sugars in Foods
• Added sugars in candy,
beverages, cereals
• Natural sugars in milk,
fruit, some vegetables
Nutrition Labeling of Sugars
• Nutrition labels list total amounts of monoand diglycerides per serving under “sugars”
• All simple sugars must be listed in order of
weight in the ingredients
Labeling Sugars
What’s So Bad About Sugar?
• Simple sugars provide only calories
• Sweetened foods are often high in fat, low in
nutrients
• Problems associated with high sugar intake:
• Increased blood triglycerides
• Excessive calorie intake
• Tooth decay
Advice on Sugar Intake
• Limit added sugars to 10% or less of total
calorie intake
Alcohol Sugars
• Alcohol sugars (“polyols”)
• Simple sugars containing an alcohol group in their
molecular structure
• Incompletely digested (~2 calories/gram)
• Examples:
• Xylitol, mannitol, sorbitol
• Used as sweetening agents
• Do not promote tooth decay
Products With Alcohol Sugars
Artificial Sweetener Facts
• Artificial (non-nutritive) sweeteners
• Not significant sources of energy or nutrients
• 160 to 13,000 time sweeter than sucrose
• Do not promote tooth decay
Products with Artificial Sweeteners
Artificial Sweeteners
Artificial Sweeteners
• Saccharin
• First artificial sweetener (1800s)
• 300 times sweeter than sucrose
• Aspartame (Nutrasweet)
• Contains amino acids phenylalanine, aspartame
• 4 calories/gram
• 200 times sweeter than sucrose
Is Aspartame Safe?
• Products containing aspartame must carry a
warning for people with certain conditions
• Phenylketonuria (PKU)
• Genetic disorder
• Lack of enzyme phenylalanine hydroxylase
causes phenylalanine buildup in blood
Safe Limits for Aspartame
• Safe levels of
aspartame set at 50
mg/kg body weight/day
• Some individuals report
sensitivity to small
amounts
Artificial Sweeteners cont.
• Sucralose (Splenda)
• Made from sucrose
• 600 times sweeter than sucrose
• Acesulfame K (Sunette, Sweet One)
• Acesulfame potassium
• 200 times sweeter than sucrose
Artificial Sweeteners cont.
• Neotame
• Like aspartame, made from phenylalanine and
aspartame, but not harmful to people with PKU
• 7,000-13,000 times sweeter than sucrose
• Rebiana (Reb-A, Truvia, Purevia)
• Derived from herb stevia
Stevia-Based Sweeteners
Sweetness Rankings
• Artificial and natural
sweeteners, in order of
sweetness
Complex Carbohydrate Facts
• Complex carbohydrates
• Form of carbohydrate found in starchy
vegetables, grains, dried beans, and many types
of dietary fiber
• The most common form of starch is made of long
chains of glucose units
Complex Carbohydrate Facts
• Polysaccharides
• Carbohydrates containing many molecules of
monosaccharides linked together
• 3 major types: starch, glycogen, dietary fiber
• Oligosaccharides
• Polysaccharides consisting of 3 to 10
monosaccharides
Which Foods Have Carbohydrates?
Which Has More Calories?
• 4 oz baked potato
• 122 calories
• 3 oz lean hamburger
• 239 calories
US Fiber Facts
• Fiber is low in calories, prevents constipation,
and may lower risk of heart disease, obesity,
and diabetes
• Recommended intake 28-35 grams/day
• Fiber intake by US children and adults is low:
about 15 grams of fiber/day
Good Sources of Fiber
Good Sources of Fiber
Types of Fiber
• Edible fibers are classified based on source
and effects on body processes
• Functional fiber
• Dietary fiber
• Total fiber
Functional Fiber
• Functional fiber
• Specific types of nondigestible carbohydrates that
have beneficial effects on health
• Examples: psyllium, pectin, gels, gums
• Effects:
• Feeling of fullness, slows glucose absorption,
prevents constipation, decreases fat and
cholesterol absorption
Dietary Fiber
• Dietary fiber
• Naturally occurring, intact forms of nondigestible
fiber in plants and “woody” plant cell walls
• Contains nutrients and other plant substances
• Found in oat and wheat bran; plant cellulose,
fruits and vegetables, raffinose in beans
Dietary Fiber In Wheat Bran
Total Fiber
• The recommended daily intake of fiber is
based on total fiber
• Total fiber
• The sum of functional and dietary fiber
Soluble and Insoluble Fiber
• Soluble fibers combine chemically with water
• Found in oats, barley, fruit, psyllium
• Slows glucose absorption
• Reduces fat and cholesterol absorption
• Insoluble fibers do not combine chemically
with water
• Found in bran, some legumes
• Same health benefits as soluble fiber
Adding Fiber to Your Diet
• Adding too much fiber to the diet too quickly
can result in temporary side effects
• Increase fluid intake along with fiber intake
• Don’t add excessive fiber to children’s diets
Carbohydrates and Blood Glucose
• Some types of simple and complex
carbohydrates in foods elevate blood glucose
levels more than others
• Important to people with insulin resistance
and type 2 diabetes
Key Terms
• Insulin resistance
• When cell membranes have reduced sensitivity to
insulin, more insulin is required to transport a
given amount of glucose into cells
• Type 2 diabetes
• High blood glucose levels due to the body’s
inability to use insulin normally, or to produce
enough insulin
Glycemic Index
• Carbohydrate-containing foods are classified
by how much they increase blood glucose
• Glycemic index
• Measure of how much blood glucose is raised by
a 50-gram portion of a carbohydrate-containing
food, compared to 50 grams of glucose or white
bread
Glycemic Index of Foods
• Some high glycemic-index foods:
• Glucose, white bread, baked potatoes, jelly beans
• Some low glycemic-index foods:
• Fructose, xylitol, hummus, apples, all-bran cereal
Low Glycemic Index Diets
• Diets with low glycemic index carbohydrates:
• Improve blood glucose control
• Reduce elevated blood cholesterol and
triglycerides
• Increase beneficial HDH cholesterol
• Decrease risks of type 2 diabetes, some types of
cancer, and heart disease
Carbohydrates and Your Teeth
• Tooth decay did not become a problem until
sugar became widely available
• Tooth decay (dental caries, cavities)
• Disintegration of teeth due to acids produced by
bacteria in the mouth that feed on sugar
Sugars From Starchy Foods
• Enzymes in the mouth
break down starches
into simple sugars
• ”Happy Tooth” symbol
used in Europe to
indicate foods safe for
teeth
Tooth Decay: More Than Sugar
• Stickiness and frequent consumption of
sugary/starchy foods increases tooth decay
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Eating sticky foods
Eating sugary foods between meals
Frequently sipping sweetened beverages
Chewing sugary gum
“Stickiness”
Sugar and Tooth Decay
• Sugar feeds bacteria that live in the mouth
and secrete acids that dissolve teeth
• Plaque
• Soft, sticky, white material on teeth
• Formed by bacteria
Foods That Don’t Promote Decay
Water Fluoridation
• Addition of fluoride to community drinking
water supplies reduces the incidence of tooth
decay by 50% or more
• Fluoride is also added to toothpastes, rinses
and gels, and to protective sealants
Baby Bottle Caries
• Infants and small
children who fall asleep
while sucking a bottle
may develop severe
decay
• Fluid pools around the
upper front teeth