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LIPIDS: THE CONDENSED
ENERGY
CHAPTER 5
Copyright © 2010, 2005, 1998 by Saunders, an imprint of Elsevier Inc.
Lipids: The Condensed Energy
 In 2006, added fats and
oils provided more
calories/day for the
average American than
any other food group
 NHANES data find that
only 17%–20% of
population meets the
guidelines of <30% of
calories from fat
Copyright © 2010, 2005, 1998 by Saunders, an imprint of Elsevier Inc.
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Classification of Fats
 Simple lipids can be
found in foods and in the
body
 Triglycerides
 Fatty acids
 Structural lipids are
produced by the body
 Lipoproteins
 Phospholipids
From Thibodeau GA, Patton KT: Anatomy & Physiology, ed
6. St. Louis, Mosby, 2007.
Copyright © 2010, 2005, 1998 by Saunders, an imprint of Elsevier Inc.
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Classification of Fats:
Simple Lipids
 Simple lipids
 Saturated fatty acids (SFAs)
 Primarily in animal products (meat and dairy)
 Implicated in causing  in total and LDL
cholesterol causing an  risk for CVD
Barbara Cousins. In Thibodeau GA, Patton
KT (eds): Anatomy & Physiology, ed 6. St.
Louis: Mosby, 2007.
 Monounsaturated fatty acids (MUFAs)
 Primarily in plant foods (olive oil, canola oil,
peanuts, pecans, almonds, avocados)
  HDL cholesterol, which has a protective
effect for CVD
Copyright © 2010, 2005, 1998 by Saunders, an imprint of Elsevier Inc.
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Classification of Fats:
Simple Lipids
 Trans fatty acid
 Found in meats, dairy, stick margarine,
shortening, salty snacks, high-fat baked
goods, commercial frying fats
 High intakes result in elevated total and
LDL cholesterol
 Effective January 1, 2006, FDA required
food labels to declare the amounts of
trans fat on nutrition labels
Copyright © 2010, 2005, 1998 by Saunders, an imprint of Elsevier Inc.
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Classification of Fats:
Simple Lipids
 Polyunsaturated fatty acids (PUFAs)
 Essential fatty acids (EFAs)
 Linoleic acid (omega-6 FA)—coldwater marine
fish, soybean and canola oils, leafy vegetables


Involved in development and function of retina and
cerebral cortex
 HDL is protective for CVD
 Linolenic acid (omega-3 FA)—vegetable oils
like corn, safflower, soybean, sunflower
Barbara Cousins. In Thibodeau GA, Patton
KT (eds): Anatomy & Physiology, ed 6. St.
Louis: Mosby, 2007.


Functions in growth, reproduction, and maintenance of
skin integrity
May  risk of CVD
Copyright © 2010, 2005, 1998 by Saunders, an imprint of Elsevier Inc.
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Classification of Fats:
Compound Lipids
 Phospholipids make up 40% of cell membrane
(e.g., enamel and dentin)
 Synthesized in the body or obtained from the diet
 Lipoproteins transport insoluble
fats in the blood




High-density lipoproteins (HDLs)
Low-density lipoproteins (LDLs)
Very low-density lipoproteins (VLDLs)
Chylomicrons
 Cholesterol
 Precursor for hormones and structural
component
From Thibodeau GA, Patton KT: Anatomy &
Physiology, ed 6. St. Louis: Mosby, 2007.
Copyright © 2010, 2005, 1998 by Saunders, an imprint of Elsevier Inc.
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Physiological Roles
 Concentrated source of energy
 Spares protein
 Satiety value
 Palatability
 Aids absorption of fat-soluble vitamins
 Provides EFAs
 Adipose tissue serves as an energy reserve
 Cushions vital organs
 Provides insulation and maintains body temperature
Copyright © 2010, 2005, 1998 by Saunders, an imprint of Elsevier Inc.
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Dietary Fats and Dental Health
 Decreased incidence of caries through the
following:
 Inhibits streptococcal growth
 May reduce dissolution of hydroxyapatite by acids
 Fat may act as a protective layer and prevent
adherence of retentive CHOs or enhance clearance
 May delay gastric emptying, enhancing
fluoride absorption
From Darby ML, Walsh MM: Dental
Hygiene: Theory and Practice, ed 2. St.
Louis: Saunders, 2003.
Copyright © 2010, 2005, 1998 by Saunders, an imprint of Elsevier Inc.
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Dietary Fats and Dental Health
 Periodontal disease
 Studies using 3000 mg of n-6 PUFA and n-3
PUFA
 n-6 PUFA
  gingival inflammation (significant at

p <0.016 level)
 in levels of prostaglandins, arachidonic acid,
and leukotrienes
  in pocket depth with n-3 (fish oil) and n-6
(borage oil)
Copyright © 2010, 2005, 1998 by Saunders, an imprint of Elsevier Inc.
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Dietary Requirements
 AMDR for total fat 20%-35% of
energy intake
 Keep intake of saturated fat, trans
fat, and dietary cholesterol as low as
possible while still consuming a
nutritionally adequate diet
 AI for alpha-linolenic acid = 1.1 to
1.6 g/day
 AI for linoleic acid = 12-17 g/day
Copyright © 2010, 2005, 1998 by Saunders, an imprint of Elsevier Inc.
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Sources
 Principal sources of fat in US
diet
 Fats and oils
 Red meats, poultry, and fish
 Dairy products
 Combined they account for
about 90% of total fat intake
Copyright © 2010, 2005, 1998 by Saunders, an imprint of Elsevier Inc.
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Overconsumption and
Health-Related Problems
 Obesity
 Excessive fat stores is a common disorder
 Blood lipid levels (hyperlipidemia)
 Strongest dietary determinant of the blood
cholesterol level is dietary saturated fat
 Trans fats increase risk of CVD 2- to 10-fold
 Cancer
 Possible link to high-fat diet, but research continues
Copyright © 2010, 2005, 1998 by Saunders, an imprint of Elsevier Inc.
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Underconsumption and
Health-Related Problems
 EFA deficiency
 Symptoms include dry, scaly, skin, hair loss, impaired
wound healing, visual impairment and impaired
reproductive ability
 People at risk
 People w/fatty malabsorption syndromes
(e.g., cystic fibrosis)
 Premature babies
 Very low-fat diets (<10% of calories from fat)
Copyright © 2010, 2005, 1998 by Saunders, an imprint of Elsevier Inc.
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Fat Replacers
 Method to reduce fat intake
 National survey found 88% of US population
consumes low-fat, reduced-fat, or fat-free foods
and beverages
 Types of fat replacers
 Fat “substitutes” or “analogs”
 Contain less energy than fat
 “Fat mimetics”
 Mimic properties of fat
 Fat “barriers”
 Reduce absorption of fats during frying
Copyright © 2010, 2005, 1998 by Saunders, an imprint of Elsevier Inc.
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Fat Replacers: Classifications
 Carbohydrated
 Plant polysaccharides; include cellulose, gums,
dextrins, fiber, maltodextrins, starches, and
polydextrose



Thicken and add bulk, thereby producing a mouth feel similar
to fat
Provide from 1 to 4 kcal/g
Withstand heat used in frying
Copyright © 2010, 2005, 1998 by Saunders, an imprint of Elsevier Inc.
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Fat Replacers: Classifications
 Protein-based
 Form gels that provide structure and functionality
similar to that of fat
 Can’t be used at high temperatures—the protein
coagulates
 Provide 1.3 to 4 kcal/g and have biological value of
the component amino acids
 Example: Simplesse made from whey (milk protein)
and egg white
Copyright © 2010, 2005, 1998 by Saunders, an imprint of Elsevier Inc.
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Fat Replacers: Classifications
 Fat-based
 Sucrose polyester olestra (Olean)
 Fatty acids to nontraditional backbones (e.g., sugar) so
enzymes in gut are not able to cleave the fatty acids
 Heat-stable and retain their functional properties in baked and
fried foods
 Pose a risk for GI distress (intestinal discomfort, cramps, and
diarrhea) and reduce absorption of fat-soluble nutrients
Copyright © 2010, 2005, 1998 by Saunders, an imprint of Elsevier Inc.
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Nutrition Considerations
 Wise choices of dietary fats
 When selecting and preparing meat, poultry, dry
beans, and milk or milk products, choose lean, low-fat,
or fat-free
 Limit intake of fats and oils high in saturated and/or
trans fatty acids; choose products low in these
 If solid fat is added in cooking this counts
as part of discretionary calorie allowance
 Select fish rich in omega-3 fatty acids,
such as salmon, trout, and herring
Copyright © 2010, 2005, 1998 by Saunders, an imprint of Elsevier Inc.
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