Chapter Four

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Chapter Four

• The Carbohydrates
• Sugars, Starches,
• and Fibers

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Carbohydrate Quiz

• A diet high in sugar causes diabetes
• A diet high in sugar promotes dental decay
• Sugar causes misbehavior in children
• A diet high in complex CHO may protect against
  heart disease and stroke
• A high fiber diet may inhibit the absorption of
  some nutrients

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Carbohydrates - Overview

• Simple CHOs (concentrated sugars)
• Monosaccharides
• Disaccharides
• Complex CHOs
• Polysaccharides (glycogen and starches)
• Fibers (not digestible)

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Chemists View of Sugars

• 3 basic atoms
• Carbon C (binds 4)
• Hydrogen H (binds 1)
• Oxygen O (binds 2)
• Glucose
• C6H12O6
• All carbohydrates have CHO

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Simple Carbohydrates

• Monosaccharides
• Glucose
• Fructose
• Galactose
• Disaccharides
• Maltose
• Sucrose
• Lactose

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Monosaccharides (single sugars)

• Glucose
• Bodys primary source of energy
• Blood sugar dextrose
• Fructose
• Metabolized to glucose in the liver
• Sweetest tasting
• Sources Fruit, honey, high fructose corn syrup

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Monosaccharides

• Galactose
• Rarely occurs naturally as a single sugar
• Part of lactose
• Converted to glucose in the liver
• Found in dairy products

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Chemists View Monosaccharides
Fructose
Glucose
Galactose
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Condensation
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Disaccharides (Two Sugars)

• Maltose
• Found in the growing stages of plants
• Glucose Glucose
• Sucrose
• Found in table sugar honey
• Glucose Fructose
• Lactose
• Found in milk
• Glucose Galactose

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Hydrolysis

• Water molecule broken down
• Disaccharide H2O--gt 2 monosaccharides

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Complex Carbohydrates -Polysaccharides

• Starches
• Found only in plants
• 100s to 1,000s molecules of glucose
• Each society has a primary starch (corn, rice,
  wheat, potatoes)
• Glycogen
• Found only in animals (liver, muscle)
• Glucose molecules are more compacted and branched
  than starch

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Glycogen and Starch Molecules Compared (Small
Segments)
Starch (amylopectin)
Glycogen
Starch (amylose)
A starch molecule contains hundreds of glucose
molecules in either occasionally branched chains
(amylopectin) or unbranched chains (amylose).
A glycogen molecule contains hundreds of glucose
units in long, highly branched chains.
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Complex CHOs, continued

• Fibers (Indigestible polysaccharides)
• Are the structural parts of plants
• Indigestible to humans lack enzymes to break
  down bonds
• Recommended intake 20 35 grams
• Fiber is lost in refined grain products

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Starch and Cellulose Molecules Compared (Small
Segments)
Starch
Cellulose
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Types of Fibers

• Soluble, viscous, fermentable
• Gums and mucilages
• Pectins
• Psyllium
• Some hemicelluloses
• Food sources
• Legumes, oats, oat bran, barley, rye, seeds,
  apples, citrus fruits, and vegetables

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Soluble Fiber Cont.

• Actions in the body
• Lowers cholesterol binds with bile
• Slows glucose absorption by slowing transit of
  food through upper GI tract
• Softens stools by retaining moisture
• Health benefits
• Lowers risk of heart disease and diabetes

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Types of Fibers Cont.

• Insoluble, nonviscous, less fermentable
• Cellulose
• Lignins
• Psyllium
• Resistant starch
• Many hemicelluloses
• Food sources
• Brown rice, fruits, legumes, seeds, wheat bran,
  whole grains, and vegetables

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Insoluble Fiber Cont.

• Actions in the body
• Increases fecal wt. and speeds passage through
  colon
• Provides bulk and sensation of fullness
• Health benefits
• Prevents constipation
• Reduces risk of diverticulosis, hemorrhoids, and
  appendicitis
• May help with wt. management

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Excess Fiber

• Too much bulk--gt lower total food/nutrient intake
• Faster transit time may decrease absorption (Fe)
• Binders (phytic acid) may decrease availability
  of nutrients (Zn, Ca, Mg, Cu)
• Too much fiber, too soon ---gt gas, cramps
• Increase fiber gradually and increase liquids

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Digestion of Carbohydrate

• Mouth
• Starch--gt maltose (salivary amylase)
• Stomach--- None
• Small intestine
• Maltose--gt glucose glucose (maltase)
• Sucrose--gt glucose fructose (sucrase)
• Lactose--gt glucose galactose (lactase)
• Large intestine Bacteria fiber ferment FA
  gas H2O

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Figure 4-10Page 112
Carbohydrate Digestion in the GI Tract
Mouth
Salivary glands
Stomach
Stomach
(Liver)
(Liver)
(Gallbladder)
(Gallbladder)
Pancreas
Small intestine
Small intestine
Large intestine
Large intestine
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Absorption of Carbohydrate

• Monosaccharides absorbed in the small intestine
• Glucose
• Fructose
• Galactose
• Portal vein transports to liver
• Liver can store as glycogen, convert galactose
  and fructose to glucose

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Carbohydrate Absorption
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Glycemic Effect of Foods

• Blood sugars
• All CHOs--gt blood glucose over time
• How fast and how high blood sugar levels rise,
  and how quickly return to normal glycemic
  effect of food
• Glycemic index classifies foods according to
  potential for raising blood glucose
• May be useful to people with diabetes and for
  weight control

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Peanuts Soybeans Cashews, cherries Barley Milk,
kidney beans, garbanzo beans Butter
beans Yogurt Tomato juice, navy beans, apples,
pears Apple juice Bran cereals, black-eyed peas,
peaches Chocolate, pudding Grapes Macaroni,
carrots, green peas, baked beans Rye bread,
orange juice Banana Wheat bread, corn, pound
cake Brown rice Cola, pineapple Ice
cream Raisins, white rice Couscous Watermelon,
popcorn, bagel Pumpkin, doughnut Sports drinks,
jelly beans Cornflakes Baked potato White bread
LOW

• Glycemic Index of Selected Foods

HIGH
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Maintaining Blood Glucose

• Regulating Hormones
• Insulin released from the pancreas moves
  glucose into the cells lowers blood sugar levels
• Glucagon released from the pancreas brings
  glucose out of storage raises blood sugar levels

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Diabetes

• Type I diabetes
• IDDM-Insulin Dependent Diabetes Mellitus
• No insulin produced by the body
• Type II diabetes
• NIDDM-Non Insulin Dependent Diabetes Mellitus
• Fat cells resist insulin
• Prediabetes Blood glucose that is higher than
  normal but below the diagnosis of diabetes

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Lactose Intolerance

• Deficiency of lactase enzymes
• NOT a milk allergy!
• Genetic trait prevalent in some ethnic groups
• Symptoms
• Undigested lactose pulls H2O into intestines
• Bacteria use for food--gt acid gas
• Abdominal discomfort, bloating, diarrhea

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Lactose Intolerance -Treatment

• Use lactose sparingly
• Spread dairy intake throughout day
• Yogurt, small amounts of milk/dairy
• Lactaid milk, acidophilus milk
• Replace lactase enzyme
• Lactaid pills/drops

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Carbohydrate Recommendations

• Carbohydrates
• 45 65 total kcals
• RDA is 130 grams/day for adults
• Daily Values is 300 grams/day
• Food sources Whole grains, vegetables, fruits,
  beans
• Simple CHOs
• Concentrated sugars should be max 10 kcals or 10
  teaspoons per day based on a 2000 kcal diet

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From Guidelines to Groceries

• Grains encourage whole grains
• Vegetables starchy nonstarchy differ in
  carb. Content
• Fruits vary in water, fiber, sugar content
• Milk Milk products contain CHO, cheese is low
• Meat meat alternates nuts legumes contain
  CHO
• Food labels list gms of CHO, fiber, sugar

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Sugar

• Sugar in excess Nutrient deficiencies, dental
  caries
• High sugar intake--gt malnutrition (replacing
  nutritious food with empty kcals)
• Sugar promotes tooth decay
• High sugar intake may lead to
• Obesity
• May increase blood sugars
• High triglycerides--gt CVD

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Nutrients in sugar other foods
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Sugar as a Food Additive

• Added sugars sucrose, dextrose, molasses, corn
  syrup, high-fructose corn syrup, honey
• Over half the added sugars come from soft drinks
  and table sugar
• Plus added pounds of artificial sweetners per
  person per year
• Recommended intake of sugar is 10 or less of
  total days kcal intake

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Over half of the added sugars in our diet come
from soft drinks and table sugar, but baked
goods, fruit drinks, ice cream, candy, and
breakfast cereals also make substantial
contributions.
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Alternatives to Sugar

• Highlight Four

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Sugar Replacers

• Sugar alcohols
• Xylitol, sorbitol, mannitol
• 2 kcals/gram
• Sugar free does NOT mean kcal free!
• Absorbed more slowly than sucrose
• Does NOT contribute to tooth decay mouth
  bacteria cannot metabolize
• Too much can cause diarrhea

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Artificial Sweeteners

• Saccharin
• No longer suspected of causing CA
• Used primarily in soft drinks, tabletop sweetener
• Aspartame
• 2 Amino Acids not stable w/ heat
• Warning about phenylalanine for those with PKU
• General purpose sweetener
• Acesulfame Potassium (Sweet One)
• No kcals stable in cooking/liquids
• Sucralose
• Approved in 1998 600 x sweeter than sugar

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Sugar Alternatives, continued

• Alitame and Cyclamate awaiting FDA approval
• Neotame is the most recently FDA approved 8000 x
  sweeter than sugar
• Tagatose provides 1.5 kcals/gm
• Stevia can not be used as a food additive sold
  as a dietary herbal supplement
• Acceptable Daily Intake amount of artificial
  sweetener considered safe for daily use

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Figure H4-3Page 138
Sugar Alternatives on Food Labels
Products containing sugar replacers may claim to
not promote tooth decay if they meet FDA
criteria for dental plaque activity.
This ingredient list includes both sugar alcohols
and artificial sweeteners.
INGREDIENTS SORBITOL, MALTITOL, GUM BASE,
MANNITOL, ARTIFICIAL AND NATURAL FLAVORING,
ACACIA, SOFTENERS, TITANIUM DIOXIDE (COLOR),
ASPARTAME, ACESULFAME POTASSIUM AND CANDELILLA
WAX. PHENYLKETONURICS CONTAINS
PHENYLALANINE.
Products containing aspartame must carry a
warning for people with phenylketonuria.
Products that claim to be reduced
kcalories must provide at least 25 fewer
kcalories per serving than the comparison item.
35 FEWER CALORIES THAN SUGARED GUM.
Amount per serving DV Total Fat 0g
0 Sodium 0mg 0 Total
Carb. 2g 1 Sugars 0g Sugar
Alcohol 2g Protein 0g Not a significant
source of other nutrients.
Nutrition Facts Serving Size 2 pieces
(3g) Servings 6 Calories 5 Percent Daily
Values (DV) are based on a 2,000 calorie diet.
Products containing less than 0.5 g of sugar per
serving can claim to be sugarless or
sugar-free.
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Future of Artificial Sweeteners

• Since 1965, there has been a dramatic increase in
  consumption of sugar and artificial sweeteners
• Sweet tooths contributing to obesityno evidence
  these help with weight reduction
• May contribute to obesity by stimulating appetite
• What is the impact of these products over
  generations?
• Children should avoid artificial sweeteners!

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Condensation Reactions
2 monosaccharides --gt disaccharide water