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Hole’s Human
Anatomy and Physiology
Eleventh Edition
Shier w Butler w Lewis
Chapter
18
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1
Chapter 18
Nutrition and Metabolism
Nutrients – chemical substances supplied by the
environment required for survival
Macronutrients
• carbohydrates
• proteins
• fats
Micronutrients
• vitamins
• minerals
Essential Nutrients
• nutrients
human cells
cannot
synthesize such
as certain
amino acids 2
Substances Controlling Appetite
3
Hormones Control Body Weight
4
Carbohydrates
Organic compounds primarily used to supply
cellular energy
Sources
• sugars
• starches
• usually from plant
sources
• glycogen in meats
RDA is 125-175g
Excesses lead to
• obesity
• dental caries
• nutritional deficits
Deficiencies lead to
• metabolic acidosis
• weight loss
5
Carbohydrate Utilization
• oxidized for energy
• production of certain molecules (ribose, deoxyribose)
• stored in liver and muscles as glycogen
• converted to fats and stored in adipose tissue
6
Carbohydrate Utilization
7
Lipids
Organic compounds that supply energy and are used to
build cell structures
Excesses lead to
Sources
• obesity
• meats
• increased serum
• eggs
cholesterol
• milk
• increased risk of
• lard
heart diseases
• plant oils
RDA is 80-100g
Deficiencies lead to
• weight loss
• skin lesions
• hormonal imbalances
8
Lipid Utilization
• oxidized for energy
• production of triglycerides, phospholipids,
lipoproteins, and cholesterol
• stored in adipose tissue
• glycerol may be used to synthesize glycerol
9
Lipid Utilization
10
Lipid Utilization
The liver uses fatty acids to synthesize a variety of lipids.
11
Proteins
Organic compounds that serve as structural
materials, act as enzymes, and provide energy
Sources
• meats
• cheeses
• nuts
• legumes
RDA is 0.8g/kg body
weight or 10% of diet
Excesses lead to obesity
Deficiencies lead to
• extreme weight loss
• muscle wasting
• anemia
• growth retardation
12
Protein Utilization
• build cell structures
• enzymes
• hormones
• transport of oxygen
• regulation of water balance
• control of pH
• formation of antibodies
• can be converted to carbohydrates or fats
• may be broken down and oxidized for energy
13
Protein Utilization
14
Protein Utilization
15
Nitrogen Balance
• amount of nitrogen taken in is equal to amount excreted
• negative nitrogen balance develops from starvation
• positive nitrogen balance develops in growing children,
pregnant women, or an athlete in training
16
Carbohydrate, Lipid and Protein
Nutrients
17
Energy Values of Food
Calorie – indicates amount of potential energy a food contains
Carbohydrates
4.1 calories per gram
Lipids
9.5 calories per gram
Proteins
4.1 calories per gram
18
Energy Requirements
Basal metabolic rate (BMR)
• rate at which body expends energy at rest
• primarily reflects energy needed to support
activities of organs
• varies with gender, body size, body
temperature, and endocrine function
Energy needed
• to maintain BMR
• to support muscular activity
• to maintain body temperature
• for growth in children and pregnant
women
19
Energy Balance
• occurs when caloric intake in the form of food
equals caloric output from BMR and muscular
activities
• positive energy balance leads to weight gain
20
Desirable Weight
• most common nutritional disorders involve caloric
imbalances
• overweight is defined as exceeding desirable weight
by 10% - 20%
• obesity occurs when person is 20% above desired
weight due to excess adipose tissue
21
Vitamins
• Organic compounds (other than carbohydrates, lipids
and proteins) that are essential for normal metabolic
processes
• Cannot be synthesized by body cells in adequate
amounts
22
Fat-Soluble Vitamins
• carried in lipids
• fairly resistant to heat (not destroyed by cooking and
food processing
• include Vitamins A, D, E, and K
23
Fat Soluble Vitamins
Vitamin A
• synthesized from carotenes
• stored in liver
• necessary for visual
pigments
• necessary for bone and
teeth development
• necessary for maintenance
of epithelial cells
• excesses lead to nausea,
headache, dizziness, hair
loss, birth defects
• deficiencies lead to night
blindness and degeneration
of epithelial tissues
Vitamin D
• group of steroids
• stored in liver, brain, skin,
spleen, and bone
• promotes absorption of
calcium and phosphorus
• necessary for bone and
teeth development
• excesses lead to diarrhea,
calcification of soft tissues,
and renal damage
• deficiencies lead to bone
weakening
24
Fat-Soluble Vitamins
Vitamin E
• stored in muscles and
adipose tissue
• prevents oxidation of
vitamin A and some fatty
acids
• may help stability of cell
membranes
• excesses lead to nausea,
headache, fatigue, easy
bruising and bleeding
• deficiencies are rare
Vitamin K
• stored in liver
• necessary for prothrombin
synthesis
• excesses lead to jaundice
• deficiencies lead to
prolonged clotting time
25
Sources of Fat-Soluble
Vitamins
Vitamin A
• liver
• fish
• milk
• leafy green vegetables
• yellow and orange
vegetables and fruits
Vitamin K
• liver
• soy oil
• egg yolk
• leafy green vegetables
• tomatoes
• cauliflower
Vitamin E
• cereal seed oils
• salad oils
• margarine
• shortening
• fruits
• nuts
• vegetables
Vitamin D
• skin
• egg yolk
• milk
• fish liver oils
26
Water-Soluble Vitamins
• include the B vitamins and vitamin C
• B vitamins are several compounds essential for
normal cellular metabolism
• known as the vitamin B complex
27
Water-Soluble Vitamins
Thiamine
• vitamin B1
•coenzyme for carbohydrate
oxidation
•excesses are uncommon,
include vasodilation and
cardiac dysrhythmias
• deficiencies lead to
Beriberi, muscular
weakness, heart
enlargement
Riboflavin
• vitamin B2
• parts of enzymes and
coenzymes (FAD)
•deficiencies lead to
dermatitis and blurred
vision
28
Water-Soluble Vitamins
Niacin
• vitamin B3
•parts of coenzymes (NAD)
•excesses lead to flushing,
vasodilation, wheezing, or
liver problems
•deficiencies lead to
pellagra, dermatitis,
diarrhea, or mental
disorders
Pantothenic Acid
• vitamin B5
•part of coenzyme A
• deficiencies are rare; may
lead to loss of appetite,
mental depression and
muscle spasms
29
Water-Soluble Vitamins
Vitamin B6
• group of three chemically
similar compounds
• part of coenzymes needed
for synthesis of proteins
•excesses lead to numbness,
clumsiness and paralysis
• deficiencies lead to
vomiting and convulsions
Cyanocobalamin
• vitamin B12
• part of coenzyme needed
for nucleic acid synthesis
• plays role in myelin sheath
formation
• needed for RBC formation
• deficiencies lead to
pernicious anemia
30
Water-Soluble Vitamins
Folacin
• folic acid
• coenzyme required for
amino acid and nucleic acid
metabolism
• needed for normal RBC
production
• deficiencies lead to
megaloblastic anemia
Biotin
• coenzyme required for
metabolism of amino acids,
fatty acids, and nucleic acids
• deficiencies are rare; may
lead to elevated blood
cholesterol, fatigue, nausea,
and anorexia
31
Water-Soluble Vitamins
Ascorbic acid
• Vitamin C
• needed for collagen
production and metabolism
of some amino acids
• promotes absorption of
iron and synthesis of
hormones from cholesterol
• deficiencies lead to scurvy,
lowered resistance, and slow
wound healing
32
Sources of Water-Soluble
Vitamins
Thiamine
• meats
• liver
• leafy green
vegetables
• eggs
• cereals
• legumes
Niacin
• liver
• meats
• peanuts
• legumes
Riboflavin
• milk
• leafy green vegetables
• meats
Pantothenic acid
• meats
• cereals
• legumes
• milk
• vegetables
33
Sources of Water-Soluble
Vitamins
Vitamin B6
• meats
• cereals
• peanuts
• milk
• bananas
• avocados
Folacin
• cereals
• legumes
• milk
• leafy green vegetables
Cyanocobalamin
• meats
• milk
• liver
• cheese
• eggs
Biotin
• egg yolk
• liver
• legumes
• nuts
• mushrooms
34
Sources of Water-Soluble
Vitamins
Ascorbic acid
• egg yolk
• liver
• legumes
• nuts
• mushrooms
35
Minerals
• inorganic elements that are essential in human
metabolism
• usually extracted from the soil by plants
• obtained by humans from plant foods or
animals that have eaten plants
• responsible for roughly 4% of body weight
36
Minerals
Major Minerals
• calcium
• phosphorus
• potassium
• sulfur
• sodium
• chlorine
• magnesium
Trace Elements
• iron
• manganese
• copper
• iodine
• cobalt
• zinc
• fluorine
• selenium
• chromium
37
Major Minerals
Calcium
• mostly in inorganic salts of bones and teeth
• needed for bone structure
• essential for nerve impulse conduction
• essential for muscle fiber contraction
• essential for blood coagulation
• increases permeability of cell membranes
• activates certain enzymes
• excesses lead to kidney stones, deposition of calcium
phosphate in soft tissues
• deficiencies lead to stunted growth, misshapen or fragile
bones or tetany
38
Major Minerals
Phosphorus
• mostly in inorganic salts of bones and teeth
• needed for structure of bones and teeth
• component in nearly all metabolic processes
• constituent of ATP, nucleic acids, many proteins,
enzymes, and some vitamins
• deficiency leads to stunted growth
39
Major Minerals
Potassium
• widely distributed
• maintains intracellular osmotic pressure and pH
• promotes metabolism
• required for muscle contraction and nerve impulse
conduction
• excesses are uncommon
• deficiency leads to muscular weakness, cardiac
abnormalities, and edema
40
Major Minerals
Sulfur
• widely distributed
• abundant in skin, nails, and hair
• component of certain amino acids,
thiamine, biotin, and mucopolysaccharides
41
Major Minerals
Sodium
• widely distributed
• maintains osmotic pressure of extracellular fluids
• regulates water movement in and out of cells
• required for nerve impulse conduction and
contraction of muscle fibers
•excesses lead to edema, hypertension and shrinkage
of body cells
• deficiency leads to muscle cramps and convulsions
42
Major Minerals
Chlorine
• most concentrated in cerebrospinal fluid and gastric juice
• helps maintain osmotic pressure of extracellular fluids
• regulates pH
• essential for formation of hydrochloric acid
• aids in transport of carbon dioxide
• deficiency leads to muscle cramps
43
Major Minerals
Magnesium
• abundant in bones
• required in metabolic reactions for ATP production
• helps breakdown of ATP to ADP
• excess leads to diarrhea
• deficiency leads to neuromuscular disturbances
44
Trace Elements
• are essential minerals found in minute amounts
• each makes up less than 0.005% of body weight
• include
• iron
• manganese
• copper
• iodine
• cobalt
• zinc
• fluorine
• selenium
• chromium
45
Trace Elements
Iron
• part of hemoglobin
• catalyzes formation
of vitamin A
• incorporated into
some enzymes
Manganese
• occurs in enzymes
required for fatty acid
and cholesterol
synthesis, formation of
urea, and functioning
of the nervous system
Copper
• essential for hemoglobin
synthesis, bone development,
melanin production and myelin
formation
46
Trace Elements
Iodine
• component of thyroid hormone
Cobalt
• required for synthesis of several enzymes
Zinc
• component of many enzymes
• necessary for wound healing and maintaining
integrity of skin
47
Trace Elements
Fluorine
• component of tooth structure
Selenium
• occurs in enzymes
Chromium
• essential for use of carbohydrates
48
Healthy Eating
49
Malnutrition
• poor nutrition
• undernutrition – deficiency of essential nutrients
• overnutrition – excess of nutrient intake
• primary malnutrition – malnutrition from diet alone
• secondary malnutrition – adequate diet but
individual characteristics make diet insufficient
50
Starvation
• healthy human can survive 50-70 days without food
• symptoms include low blood pressure, slow pulse,
chills, dry skin, hair loss, and poor immunity
• marasmus – lack of all nutrients
• kwashiorkor – protein starvation
• anorexia nervosa – eating disorder; self-starvation
• Bulimia – eating disorder; bingeing and purging
51
Life-Span Changes
• BMR rises in early childhood and peaks in
adolescence
• BMR declines in adulthood
• change in nutrition often reflects effects of
medical conditions and social and economic
circumstances
52