Transcript Chapter_003

CARBOHYDRATE: THE
EFFICIENT FUEL
CHAPTER 3
Copyright © 2010, 2005, 1998 by Saunders, an imprint of Elsevier Inc.
Carbohydrate: The Efficient Fuel
 The popular belief that carbohydrates have some
mysterious “fattening” power is unfounded. They:
 Add variety and palatability to the diet
 Are the most economical form of energy
 Americans like
it sweet
 Average intake is
139 pounds annually
 Need to choose more
whole grains
From Wells HF, Buzby JC: High-fructose corn syrup usage may be leveling off.
Amber Waves, February 2008, USDA.
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Classification: Simple Sugars
 Monosaccharides
 Glucose-dextrose, fruits, vegetables, corn syrup, honey
 Fructose-levulose, fruits, vegetables, corn syrup, honey
 Galactose-lactose
 Disaccharides
 Lactose—milk only
 Maltose—beer, cereals
 Sucrose—cane, beet, maple sugar,
fruits, vegetables
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Classification: Other Nutritive
Sweeteners—Sugar Alcohols
 Sugar alcohols or polyols sweeten with less
energy per gram than sucrose (averaging
2.4 kcal/g)
 Common characteristics
 Provide calories but are used in smaller amounts
 Potential to cause gastric upset
 Sorbitol and mannitol
 Essentially noncariogenic
 Maximum recommended amount <20 g/day
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Classification: Other Nutritive
Sweeteners—Sugar Alcohols
 Xylitol
 The only CHO that is anticariogenic
 Mechanisms of action against caries:
 Inhibits growth of cariogenic bacteria (Streptococcus mutans)
 Inhibits plaque growth
 Decreases transmission of cariogenic bacteria
 Promotes remineralization
 Complements fluoride toothpaste use
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Classification: Non-Nutritive
Sweeteners
 Five non-nutritive sweeteners with intense
sweetening power have FDA approval
 Aspartame (phenylalanine and aspartic acid—two AAs)
 NutraSweet and Equal
 Saccharin (derivative of petroleum)
 Sweet’n Low
 Acesulfame-K
 Sweet One
 Sucralose
 Splenda
 Neotame
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Alternative Sweeteners
Name/Brand Name
Sweetness Compared to
Sucrose
Sorbitol
0.5x
Mannitol
0.7x
Xylitol
1.0x
Saccharin (Sweet’n Low)
200–700x
Aspartame (NutraSweet & Equal)
160–220x
Acesulfame-K (Sunett)
200x
Sucralose (Splenda)
600x
Neotame (not yet available)
8000x
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Classification: Polysaccharides
(Complex CHOs)
 Starch-grains, legumes and potatoes
 Amylose
 Amylopectin
 Fiber
 Soluble
 Gums and mucilages: barley, legumes, oat bran
 Pectin: fruit
 Insoluble: speed stool through bowel reducing contact
w/carcinogens



Cellulose: wheat bran
Hemicellulose: cereals, vegetables, legumes, fruit/vegetable skins
Lignin: vegetables
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Physiologic Roles of CHO
 Provides energy
 Sole source of energy for the
RBCs, brain (CNS) and lens of the
eye
 Required for oxidation of fats
 Required for components
needed for development of
collagen and nervous tissue
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Physiologic Roles of CHO
 Spares protein
 Provides the chemical structure that combines
with nitrogen to form nonessential amino acids
 Nondigestible CHOs
 Involved in growth of bacteria in the gut that
synthesize nutrients
 Involved in gastric motility
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Carbohydrate Recommendations
 First RDA set for total CHO in
2002
 Minimal level to support brain
activity
 RDA: 130 g/day
 Dietary reference intake
recommendations
 AMDR for CHO: 45%-65%
 Focus on whole grains, legumes,
vegetables, fruits, and low-fat dairy
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Fiber Recommendations
 AI for fiber intake
 Men 19-50 yr: 38 g/day
 Women 19-50 yr: 25 g/day
 How much fiber?
 Apple (4 g)
 1½ cups salad greens (2 g)
 1 slice white bread (0.5 g)
vs. 1 slice whole wheat bread (2 g)
 ½ cup cooked beans (7.5 g)
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Added Sugar Guidelines
 MyPyramid
 Discretionary calories includes
added sugars and fat

Calorie allowances are very
small:100–300 calories
 Dietary reference intakes
 Maximal intake 25% of energy
intake
 As intakes of added sugars ,
intake of vitamins A, Fe, Ca, Zn 
 Age groups most likely to exceed
25% are 9–18 years
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Sources
 Milk
 Only animal product with significant quantities of CHO
 Whole grains
 Fruit
 Vegetables
 Potatoes, beets, corn, peas
 Legumes
 Added sugars
 Baked goods
 Jams, jellies, honey, syrups
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Hyperstates and Hypostates
 Excess carbohydrates
 Evidence suggests CHO intake at current levels does
not directly contribute to chronic disease

Rather excess intake may result in energy imbalance and
weight gain
 WHO recommends limiting intake to 10% of total
calories vs. DRI maximum intake of 25% of calories
from added sugars
 Rise in consumption of soft drinks has
negatively affected milk consumption
 Sugar is not the cause of obesity; it is intake of excess
calories whether from CHO, protein, fat, or alcohol
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Hyperstates and Hypostates
 Carbohydrate does not independently cause
caries
 Dental caries is a process involving a tooth, bacteria
and environment factors (e.g., saliva, CHO, fluoride)
 Sucrose promotes the volume and growth rate of
plaque biofilm
 Promote production of used to facilitate adherence of
plaque biofilm to the tooth
 Metabolism of sucrose by bacteria lowers the pH,
leading to decalcification
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Hyperstates and Hypostates
 Studies have not correlated caries rate with total
sugar consumption
 Danger of soda and energy drinks is acidic content in
addition to fermentable CHO content
 Cooked and refined carbohydrates readily
hydrolyzed by salivary amylase to lower pH and
demineralize enamel
 Cariogenicity of CHO is most
affected by:
 Frequency of consumption
 Form of CHO (e.g., liquid, sticky, solid)
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Nutritional Directions
 Limit between-meal snacks; eat cariogenic foods
with a meal
 Include whole grains, vegetables, whole fruits,
and low-fat dairy as snacks
 Limit simple and retentive CHOs like crackers, soft
drinks, sports drinks, fruit juice
 Recommend xylitol gum and/or mints when
brushing is not possible
 Use calcium-rich foods such as low-fat cheese or
low fat-milk for snacks
 Encourage daily self-care and home fluorides
 Refer patients with complex medical issues
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