Transcript Chapter 4

Chapter 4
The
Carbohydrates:
Sugar, Starch,
and Fiber
Ask Yourself
True or False?
1. Fruit sugar (fructose) is less fattening than
table sugar (sucrose).
2. Foods high in complex carbohydrate (starch
and fiber) are good choices when you are
trying to lose weight.
3. People with diabetes should never eat sugar.
4. The primary role of dietary fiber is to provide
energy.
5. The brain demands the sugar glucose to fuel
its activities.
Ask Yourself
6. Honey and refined sugar are the same as far
as the body is concerned.
7. Of all the components of foods that increase
one’s risk of diseases, sugars are probably
the biggest troublemakers.
8. Breads that are brown in color have more
fiber than white bread.
9. Some foods labeled sugar-free actually
contain calorie-bearing sugars.
10. Artificial sweeteners are safe to use in
moderation.
The Body’s Need for Carbohydrates
• The primary role of carbohydrates is to
provide the body with energy (calories).
• Carbohydrates are the preferred fuel for the
brain and nervous system.
• Carbohydrates are the ideal fuel compared to
other alternatives:
 Less expensive than protein.
 High-fat diets are associated with chronic
disease.
Carbohydrate Basics
Carbohydrates
Compounds made of single sugars or multiples of
them and composed of carbon, hydrogen, and
oxygen atoms.
 carbo = carbon (C)
 hydrate = water (H2O)
Complex carbohydrates
Long chains of sugars (glucose) arranged as
starch or fiber. Also called polysaccharides.
 poly = many
 saccharides = sugar unit
Simple carbohydrates (sugars)
Single sugars (monosaccharides) and the pairs
of sugars (disaccharides) linked together.
Carbohydrate Basics
• Carbohydrate-rich foods are
obtained almost exclusively from
plants.
Milk is the only animal-derived
food that contains significant
carbohydrate.
• All carbohydrates are composed of
single sugars, alone or in various
combinations.
Simple Carbohydrates
• Glucose is made of
water and carbon
dioxide.
 Plants use energy
from the sun to
synthesize it.
• The atoms in a
glucose molecule can
be rearranged by
plants to form
fructose, too.
Simple Carbohydrates
• Single Sugars - Monosaccharides:
 Glucose
The building block of carbohydrate; a single
sugar used in both plant and animal tissues as
quick energy. A single sugar is known as a
monosaccharide.
• mono = one
 Fructose
Fruit sugar—the sweetest of the single sugars.
 Galactose:
Another single sugar that occurs bonded to
glucose in the sugar of milk.
Simple Carbohydrates
• Double Sugars - Disaccharides:
 Sucrose:
A double sugar composed of glucose and
fructose. A double sugar is known as a
disaccharide.
• di = two
 Maltose
A double sugar composed of two glucose units.
 Lactose
A double sugar composed of glucose and
galactose; commonly known as milk sugar.
Simple Carbohydrates
A sampling of foods
providing added sugars
to the diet.
Added Sugars:
• Sugar cane and sugar
beets are purified to
make sucrose.
• Food examples include
white (table) sugar,
brown sugar, powdered
sugar.
• Sucrose is common in
sweets.
Simple Carbohydrates
• Enzymes
• Lactose intolerance
Inability to digest
Protein catalysts. A
lactose as a result of a
catalyst facilitates a
lack of the necessary
chemical reaction
enzyme lactase.
without itself being
 Symptoms include
altered in the
nausea, abdominal pain,
process.
diarrhea, or excessive
 Utilized in the
gas that occurs
brewing process to
anywhere from 15
minutes to a couple of
break down starch in
hours after consuming
barley and wheat into
milk or milk products.
maltose
Complex Carbohydrates: Starch
Complex carbohydrates include starch and
fiber. All starchy foods are plant foods.
•Starch
A plant polysaccharide composed of hundreds
of glucose molecules, digestible by human
beings.
•Polysaccharide
A long chain of 10 or more glucose molecules
linked together in straight or branched chains;
another term for complex carbohydrates.
Complex Carbohydrates: Starch
Sources of starch
include:
• Seeds such as
grains, peas and
beans.
• Legumes including
dried beans, lentils
and soybeans.
• Root vegetables
(yams) and tubers
(potatoes).
Complex Carbohydrates: Starch
• Most societies have a staple grain that
provides most of the people’s food
energy.
• Staple grain
A grain used frequently or daily in the
diet. Examples include:
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Corn in Mexico
Rice in Asia
Wheat in Canada, Europe and USA
Millet, rye, barley, and oats
Complex Carbohydrates: Starch
• Refined:
Refers to the process by which the coarse parts
of food products are removed.
• Enriched
Refers to a process by which the B vitamins
thiamin, riboflavin, niacin, folic acid, and the
mineral iron are added to refined grains and
grain products at levels specified by law.
• Fortified foods
Foods to which nutrients have been added.
Typically, commonly eaten foods are chosen for
fortification with added nutrients to help
prevent a deficiency of a nutrient (iodized salt,
milk with vitamin D) or to reduce the risk of
chronic disease (juices with added calcium).
Complex Carbohydrate: Starch
A Whole Grain:
• Germ
The nutrient-rich and fat-dense
inner part of a whole grain.
• Endosperm
Provides energy; contains
starch grains embedded in a
protein matrix.
• Bran
Fibrous protective covering of a
whole grain; source of fiber, B
vitamins, and trace minerals.
• Husk (Chaff)
The outer, inedible covering of
a grain.
Complex Carbohydrates: Starch
• Whole grain
Refers to a grain that is milled in its entirety (all but
the husk), not refined.
 Whole grains include wheat, corn, rice, rye, oats, barley,
amaranth, buckwheat, sorghum, and millet; two others—
bulgur and couscous—are processed from wheat grains.
Complex Carbohydrates: Fiber
• Fiber:
The indigestible residues of food, composed
mostly of polysaccharides. The best known
fibers are cellulose, hemicellulose, pectin, and
gums.
 Comes from the supporting structures of
plants: leaves, stems and seeds.
 Cannot be broken down by human digestive
enzymes although some may be broken down
by bacteria residing in the digestive tract.
 Fiber has few if any calories because it is not
digested.
Complex Carbohydrates: Fiber
• Insoluble fiber
• Includes the fiber
types called
cellulose,
hemicellulose, and
lignin.
• Insoluble fibers do
not dissolve in
water.
• Soluble fiber
• Includes the fiber
types called pectin,
gums, mucilages,
some hemicelluloses,
and algal substances
(for example,
carageenan).
• Soluble fibers either
dissolve or swell when
placed in water.
Foods rich in insoluble fiber:
Bran
Rice
Foods rich in soluble fiber:
Barley
Legumes
Brown rice
Seeds
Broccoli
Oat bran
Green beans
Skins/peels
Carrots
Oats
Green peas
Wheat bran
Corn
Potatoes
Many veggies
Whole-grain
products
Fruits
Rye
Nuts
Insoluble fiber:
• Holds water in the
colon and increases
bulk to the stool.
• Stimulates muscles
and helps maintain
health and tone.
Soluble fiber:
• Binds cholesterol
compounds and may
lower blood
cholesterol.
• Improves body’s
handling of glucose.
We are advised to
increase our intakes of
complex carbohydrates.
Choose plenty of whole
foods like this…
…and fewer foods like
these—foods that no
longer resemble their
original farm-grown
products.
Choosing Carbohydrates
• Whole food
A food that is altered as
little as possible from
the plant or animal
tissue from which it was
taken—such as milk,
oats, potatoes, or
apples.
 The more a food
resembles the original,
farm-grown product, the
more nutritious it is
likely to be.
Choosing Carbohydrates
Fiber in the Diet
• Diets high in fruits,
vegetables and
legumes will provide
high fiber
• Too much fiber can
cause dehydration,
intestinal discomfort
and limit absorption
of iron and other
nutrients
Choosing Carbohydrates
Added Sugars: Use Discretion
• Reduce the intake of calories from
added sugars. (Dietary Guidelines).
 Added Sugar
Sugars and other caloric sweeteners
that are added to foods during
processing or preparation. Added
sugars do not include naturally
occurring sugars that are found in milk
and fruit.
Choosing Carbohydrates
• Choose most often the naturally
occurring sugars (DRI).
• For those who meet their nutrient
needs, maintain a “healthy body
weight” and still need additional
calories--maximum intake = 25%
or less for added sugars (DRI).
Choosing Carbohydrates
• Small amounts of added
sugars allowed within
MyPlate calorie
allowance:
Consistently build
your diet using
nutrient-dense
foods, low in added
sugars.
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3 tsp. for 1,600 calories
5 tsp. for 1,800 calories
8 tsp. for 2,000 calories
9 tsp. for 2,200 calories
12 tsp. for 2,400 calories
Whole Grains for Health
• Incorporate whole
grains into your
diet.
1. Count to 3
2. Keep it varied
3. Check the label
Make Half Your Grains Whole
• Breakfast: Try a higher-fiber grain: oatmeal,
whole-grain muffin, or whole-grain cereal
• Whole grains are low in fat and added sugars
• Baking recipes: Substitute whole-grain flour
for 1/4 of all-purpose flour
• Make a fiber-rich snack mix from whole grain
cereals, popcorn, and nuts
• Try whole-wheat pasta, rice, and breads
• Combine whole grains in mixed dishes
How the Body Handles Carbohydrates
• Glucose is the basic carbohydrate
unit that each cell uses for energy.
• The task of the digestive system is
to disassemble lactose, sucrose
and starch into single sugars so
they can be absorbed into the
blood.
How the Body Handles Carbohydrates
• Digestive system
The body system composed of organs and glands
associated with the ingestion and processing of
food for absorption of nutrients into the body.
• Digestion
The process by which foods are broken down into
smaller absorbable products.
• Absorption
The passage of nutrients or substances into cells
or tissues; nutrients pass into intestinal cells
after digestion and then into the circulatory
system (for example, into the bloodstream).
How the Body Handles Carbohydrates
• If the blood delivers more glucose than the
cells need, glycogen will be built.
 Glycogen
A polysaccharide composed of chains of glucose,
manufactured in the body and stored in liver and
muscle.
• As a storage form of glucose, liver glycogen
can be broken down by the liver to maintain a
constant blood glucose level when
carbohydrate intake is inadequate.
Salivary
glands
3. These simple sugars are then
absorbed into the blood and
travel to the liver; the liver
Liver
regulates the amount of
glucose circulating in
the blood in response to the
hormones insulin and
glucagon.
Gallbladder
4. Most fiber passes intact through
the digestive tract through the
large intestine, and is eventually
excreted with the feces. Some
fiber is digested by bacteria in the
large intestine.
1. Carbohydrate digestion begins in
the mouth. The salivary glands
secrete a watery fluid into the mouth
to moisten the food. An enzyme
begins digestion by splitting starch
into smaller polysaccharides and
maltose. This digestion continues
after the food is swallowed until
stomach acid and enzymes start to
digest the salivary enzymes.
Stomach
2. The pancreas produces
carbohydrate digesting
Pancreas
enzymes and releases them
through the common bile duct into
Small
the small intestine. These enzymes
intestine split polysaccharides into
disaccharides. Then enzymes on the
surface of the cells of the small
intestine break these into simple
sugars (monosaccharides).
Large
intestine Absorption of the monosaccharides
takes place in the small intestine.
When a person eats, blood glucose rises. High blood glucose stimulates
the pancreas to release insulin. Insulin serves as a key for entrance of
blood glucose into cells. Liver and muscle cells store the glucose as
glycogen. Excess glucose can also be stored as fat.
Later, when blood glucose is low, the pancreas releases glucagon, which
serves as the key for the liver to break down stored glycogen into glucose
and release it into the blood to raise blood glucose levels.
Pancreas
Insulin
Bloodstream
Body
cells
Elevated
blood
glucose
Glucose
110 mg/dL*
Normal
blood
glucose
range
Digestive
tract
70 mg/dL
Pancreas
Low
blood
glucose
Glucagon
Body
cells
Glucose
Bloodstream
Liver
Glycogen
Glucose
How the Body Handles Carbohydrates
• Insulin:
A hormone secreted by the pancreas in
response to high blood glucose levels; it
assists cells in drawing glucose from the
blood.
• Glucagon
A hormone released by the pancreas that
signals the liver to release glucose into the
bloodstream.
Carbohydrates--Friend or Foe?
• Glycemic index (GI)
A scale that ranks carbohydrate-containing foods
by how much they raise blood glucose levels
compared to a standard food such as glucose or
white bread. The glycemic load (GL) is a measure
of the extent to which blood glucose is raised by a
given amount of carbohydrate-containing food.
• Glycemic effect
The effect of food on a person’s blood glucose and
insulin response – how fast and high the blood
glucose rises and how quickly the body responds
by normalizing.
High glycemic
index foods:
French, white, other
soft breads/bagels
Rice (medium-grain)
Certain cereals
(Cheerios, Corn
Flakes, Rice Krispies)
Waffles
Mashed potatoes
Honey, regular soft
drinks, jelly beans
Pretzels
Intermediate
glycemic index
foods:
Watermelon
Cream of Wheat,
instant oatmeal,
Shredded Wheat
Sourdough & rye
breads
Low glycemic index
foods:
Whole-grain, heavy
breads
Rice (long-grain)
Bran cereals, toasted
Muesli cereal, whole
oats
Apples, oranges,
peaches
Banana, pineapple,
orange juice
Baked beans, lentils,
other legumes
Ice cream
Carrots
Popcorn
Milk, yogurt
Raisins
Sweet potatoes
Tomato soup
Hypoglycemia & Diabetes
• Hypoglycemia
An abnormally low blood glucose
concentration—below 60 to 70 mg/100 mL.
• Ketosis
Abnormal amounts of ketone bodies in the blood
and urine; ketone bodies are produced from
the incomplete breakdown of fat when glucose
is unavailable for the brain and nerve cells.
• Hyperglycemia
An abnormally high blood glucose
concentration, often a symptom of diabetes.
Diabetes
• Diabetes
A disorder (technically termed diabetes
mellitus) characterized by insufficiency or
relative ineffectiveness of insulin, which
renders a person unable to regulate the blood
glucose level normally.
 Type 1 diabetes
 Type 2 diabetes
 Gestational diabetes
Prevalence of Diagnosed Diabetes by State
Sugar and Health
• Research studies have not shown a direct link
between sugar and obesity, diabetes, heart disease,
hyperactivity in children or criminal behavior.
• Does show a link with tooth decay
• Diluted naturally occurring sugars found in milk and
fruits should not be confused with concentrated,
refined sugar foods, such as table sugar, honey, and
corn syrup. These concentrated sweets should be
used in moderation, so as not to displace needed
nutrients.
• Empty-calorie foods
A phrase used to indicate that a food supplies
calories but negligible nutrients.
Keeping a Healthy Smile
• Dental caries
Decay of the teeth, or cavities.
• Dental plaque
A colorless film, consisting of bacteria and
their by-products, that is constantly forming
on the teeth.
• Periodontal disease
Inflammation or degeneration of the tissues
that surround and support the teeth.
• Nursing bottle syndrome
Decay of all the upper and sometimes the back
lower teeth that occurs in infants given
carbohydrate-containing fluids when they
sleep, or to carry around and sip all day.
Choosing Carbohydrates
• The Dietary
Guidelines for
Americans
recommend that you
“reduce the intake of
calories from added
sugars”
Bacteria living in the mouth
feed on sugar found in foods &
release an acid that can eat
away at tooth enamel & result
in a cavity.
Dental caries: decay of the
teeth, or cavities.
Carbohydrate Consumption
HOW DID YOU DO?
 The more often you choose the items listed above, the
higher your diet is likely to be in sugars. You may need
to cut back on sugar-containing foods, especially those
you checked as “3 to 5 times a week” or more. This
does not mean totally eliminating these foods from your
diet.
Check Your Diet for Fiber
Fiber…
Sweet Talk--Alternatives to Sugar