Transcript CARBOHYDRATES

CARBOHYDRATES

Chapter 2:
Carbohydrates
Joe Pistack MS/Ed
CARBOHYDRATES
One of three energy nutrients (the others are
fats and protein)
 Manufactured by green plants in a process
known as photosynthesis
 Two major groups: sugars and starches
 All carbohydrates (CHO) are not equal in
terms of health benefits from eating
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CARBOHYDRATE COMPOSITION
Molecule – smallest quantity a substance can
be divided into without loss of its characteristics
 Element – can not be separated into simpler
parts by ordinary means – composed of atoms
 Atom – smallest particle of an element that
maintains their chemical properties
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CARBOHYDRATE COMPOSITION
Carbs are composed of the elements carbon,
hydrogen, and oxygen
 The ratio of hydrogen to oxygen is 2:1 just like
water H2O
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CARBOHYDRATE COMPOSITION
Includes monosaccharides and
disaccharides
 Mono = one and di = two
 C6H12O6 chemical formula
 Note: the same ratio of hydrogen to oxygen
as water (H2O)
 Mono is one unit of C6H12O6 and di is two
units of C6H12O6 minus one unit of H2O
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MONOSACCHRIDES
Building blocks of all other CHO
 The three monosaccharide's are glucose,
fructose, and galactose
 All mono and di saccharides end with “ose”
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MONOSACCHRIDES
Glucose is commonly called blood sugar—
the body converts all forms of sugar
consumed to glucose
 Another name for glucose is dextrose
(abbreviated D)
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 IV
fluid is frequently D5W which is 5% dextrose in
water
MONOSACCHRIDES
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Fructose is found in fruits and honey
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The sweetest monosaccharide
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The body readily changes fructose to glucose
MONOSACCHRIDES
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Galactose – comes mostly from the breakdown
of the milk sugar lactose
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Yogurt and un-aged cheese contain free
galactose
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It is the least sweet of the monosaccharide's
and it too gets converted into glucose
DISACCHARIDES
Disaccharides are two monosaccharides linked
together
 The three important disaccharides are
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 Sucrose
 Lactose
 Maltose
DISACCHARIDES
Sucrose – the most common disaccharide. Also
known as ordinary white table sugar
 Made commercially from sugar beets and
sugar cane
 Brown, granulated, and powdered are all forms
of sucrose
 Also found in molasses, maple syrup, fruits,
and vegetables
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DISACCHARIDES
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Lactose – occurs naturally only in milk
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Least sweet of the disaccharides
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Made from the monosaccharides glucose and
galactose
DISACCHARIDES
Maltose – double sugar that occurs primarily
during the digestion of starch as the body
breaks it down into simpler units
 Small amounts are found in malt, malt
products, beer, some infant formula, and
sprouting seeds
 Maltose consists of two units of glucose
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SUGAR ALCOHOLS
AKA - Sugar replacers (Suplena®), Polyols,
Nutritive sweeteners, Bulk sweeteners
 Lactitol, maltitol, isomalt, sorbitol, xylitol, and
mannitol are sugar alcohols approved and used
in the US
 Used as a 1:1 substitute for sugar
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NON-NUTRITIVE SWEETENERS
Intense Sweeteners
 Sugar substitutes such as artificial sweeteners
 Saccharine
 Do not add bulk or volume, only sweetness
 150 to 500 times as sweet as sugar
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COMPLEX CARBOHYDRATES
Also called polysaccharides
 Three nutritionally important complex carbs
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 Starch
 Glycogen
 Dietary
fiber
STARCH
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Starch—major source of carbohydrates in diet
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Primarily found in grains, starchy vegetables,
legumes, and food made from grains like cereal,
bread, and pasta
GLYCOGEN
Glycogen - animals, as well as humans,
store glucose in the in liver and skeletal
muscle tissue in the form of glycogen
 During physical activity muscle glycogen is
converted to glucose
 During sleep liver glycogen is converted to
glucose as needed
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DIETARY FIBER
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Dietary fiber refers to the food, mostly from
plants that is non digestible
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It adds bulk to our foods
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Sometimes called roughage, it sweeps out our
intestinal tract
DIETARY FIBER
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Food and Nutrition Board recommends
 Men
50 years or younger: 38 grams per day
 Women 50 years or younger: 25 grams per day
 Men over 50: 30 grams per day
 Women over 50: 21 grams per day
Average fiber intake in the United States only
15 grams per day
 Eating too much fiber not recommended
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SOLUBLE FIBER
Soluble fibers – dissolve in water and thicken
to form gels
 Include beans, oatmeal, barley, broccoli, citrus
fruit, and oat bran (particularly good source)
 Health benefit –
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 Lower
cholesterol
 Regulate blood sugar
 may promote satiety
INSOLUBLE FIBER
Insoluble fiber does not dissolve in water
 Wheat bran, corn bran, vegetables, nuts, fruit
skins, and some dry beans contain insoluble
fiber
 Health benefits –
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 promotes
regularity
 may reduce risk of some forms of cancer
 may reduce risk of diverticular disease
Everyone needs both kinds of fiber in the diet
CARBOHYDRATE FUNCTIONS
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Provides fuel
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Spares body protein
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Helps prevent ketosis
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Enhances learning and memory
CARBOHYDRATE FUNCTIONS
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Provides fuel – carbohydrates, fats, and
proteins provide energy for the body's needs
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Carbohydrates are the primary source of fuel
for all cells
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The brain is a carbohydrate dependent organ
needing a continuous and uninterrupted
supply of energy
CARBOHYDRATE FUNCTIONS
Spares body protein – if carbohydrates and
available glycogen stores are depleted, the
body can convert protein into glucose.
 In the absence of carbohydrates the body will
break down internal protein before fat
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CARBOHYDRATE FUNCTIONS
Helps prevent ketosis
 The body can not handle the excessive
breakdown of stored fat because the body
lacks the necessary resources. As a result
partially broken down fats accumulate in the
blood and form ketones, putting the body into
ketosis
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Very low carb diets are not recommended
KETOSIS
Ketosis causes fatigue, nausea, and loss of
appetite
 Detection of ketones is easily done with a urine
test looking for the presence of acetone or
diacetic acid
 Coma or death can occur in severe cases
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HEALTH AND CARBOHYDRATES
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The kinds of carbs are important
High intake of fruits and vegetables lower risk
of chronic disease
 Legumes are low fat and high in protein
 Whole grains lower risk of heart disease and
some cancers
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CONSUMPTION PATTERNS
Most of the world’s population subsists on CHO
 Much research has shown that Americans and
Canadians are eating too much of everything
(except fiber), including CHO
 Of particular concern is the excessive intake of
sugar from sweetened carbonated beverages
 Six servings of whole grains are recommended
to increase fiber intake
 Whole fruit and vegetable intakes are also lower
than recommended levels
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CARBOHYDRATE CONSUMPTION AND
DENTAL HEALTH
Genetic susceptibility
 Other factors related to cavity formation
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 Length
of time food is in the mouth
 Food texture
 Frequency of food intake
 Acidity of food
 Foods that help: aged cheeses and fibrous foods
that stimulate saliva production
CARBOHYDRATE FOOD SOURCES
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As a food source carbohydrates are broken into
two general groups
Sugar
 Starches
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CARBOHYDRATE FOOD SOURCES
Sugars – table sugar contains about 4 grams
of carbohydrates per teaspoon
 When determining a persons sugar intake
simple sugars like honey, jam, and jelly need to
be considered as well as the sugars in
carbonated beverages, ice cream, cakes pies …
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STARCHES
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Emphasis on whole grain
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Make half of your grains whole - examples are
 Oatmeal
 Whole
wheat
 Graham crackers
 Pumpernickel and Rye bread – sometimes
 Barley
CARBOHYDRATE FOOD SOURCES
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Starches – complex carbohydrates and are an
important source of fiber and other nutrients
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Whole grains are more nutritious than refined
grains as some nutrients are lost in the milling
process
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Oats are not normally milled
GRAINS
Whole grain is constructed of three general
parts
 Bran – outside shell (this gets crushed in the
milling process)
 Germ - part of the contents
 Endosperm – majority of the contents
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Most nutrition is in the bran and germ
EXCHANGES LISTS
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Lists designed to make equivalent food
substitutions based on
Portion sizes
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Food composition
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How much oatmeal would provide 15 grams of CHO?
How much fat is in orange juice?
How foods compare to each other within a
given list
–
1¼ cups strawberries = ⅓ cup grape juice
EXCHANGE LISTS
Exchange lists provide swap information for the
following groups:
 Starch/Bread Exchange
 Vegetable Exchange
 Fruit Exchange
 Milk Exchange
 Estimating the Fiber Content of Foods
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DIETARY RECOMMENDATIONS
Focus on fruits (whole fruits are better than
juices)—Eat 2 cups of fresh fruit per day
 Vary your vegetables—Eat 2½ cups per day
 Make half of your grains whole: whole-grain
cereals, whole-grain breads, corn, wholegrain rice, and whole-grain pasta
 Milk contains CHO—Eat or drink three
servings a day from this group
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