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Chapter 8
Minerals
Excellence is not a skill. It is an attitude.
Ralph Marston
Copyright © 2009, by Mosby, Inc. an affiliate of Elsevier, Inc. All rights reserved.
1
The Nature of Body Minerals
• Classes of body minerals
– Major minerals (>100 mg/day)
– Trace elements (<100 mg/day)
• Mineral metabolism
– Digestion
– Absorption
– Transport
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2
Key Concepts
• A mixed diet of varied, colorful foods with
adequate energy value is the best source
of the minerals necessary for health.
• Of the total amount of minerals a person
consumes, only a relatively limited
amount is available to the body.
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3
Major Minerals
•
•
•
•
•
•
•
Calcium - Ca
Phosphorus - P
Sodium - Na
Potassium - K
Chloride - Cl
Magnesium - Mg
Sulfur - Su
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4
Calcium
• Functions
– Bone and tooth formation
– Blood clotting
– Muscle contraction and nerve action
– Metabolic reactions – helps with:
• Absorption of B12
• Activation of pancreatic lipase
• Secretion of insulin
• Cell membrane permeability
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5
Calcium, cont’d
– Requirements
• 1000 mg/day
– Deficiency states
• Osteoporosis
– Food sources
• Milk is the major food source
• Green vegetables (broccoli, spinach, kale),
fish with bones like sardines, fortified food
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6
Osteoporosis
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7
Phosphorus
• Functions
– Bone and tooth formation
– Energy metabolism – helps with:
• Oxidation of carbohydrate, fat, and protein
• Energy and protein metabolism
• Cell function and genetic inheritance
– Component of enzymes, thiamin,
DNA/RNA
– Acid-base balance
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8
Phosphorus, cont’d
• Food sources
– All living tissue especially meats
– Milk, milk products, fish, eggs
– Plant seeds
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9
Sodium
• Functions
– Water balance
– Muscle action
– Nutrient absorption
• Deficiency states
– Rare unless excessive sweating or water intake
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10
Sodium, cont’d
• Requirements average no more than 2 gm per day
• Toxicity symptoms
– Salt sensitivity and hypertension
• Food sources
– Table salt, cured meat, canned soups, processed
food
– Vegetables –carrots, leafy greens and celery
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11
Potassium
• Functions
– Water balance
– Metabolic reactions – helps with:
• Conversion of blood glucose to glycogen
• Storage of nitrogen in muscle protein
• Production of energy
– Muscle action/ cardiac contraction
– Insulin release
– Blood pressure
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12
Potassium, cont’d
• Deficiency- American diet is low; eat your
vegetables!! Low = muscle weakness and cardiac
irregularity
• Toxicity with renal disease; excessive intake
• Food sources
– Oranges, bananas, tomato, leafy green vegetables,
whole grains, fresh meats, milk products
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13
Chloride
• Source: Table salt
• Functions
– Water balance
– Acid base balance
– Digestion
• Key element in hydrochloric acid secretion
– Respiration
• Plays a role in transport of CO2 in the blood
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14
Magnesium
• Functions
– General metabolism
• Necessary catalyst for ~300+ reactions in
cells
– Protein synthesis
– Muscle action: cardiac contractility &
premature labor
– Basal metabolic rate
• Influences secretion of thyroxine
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15
Magnesium, cont’d
• Toxicity with renal disease
• Food sources
– Nuts, soybeans, cocoa, seafood, dried beans and
peas, green vegetables, whole grains
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16
Sulfur
• Food sources
– Meat, nuts, soy, fish, cheese, eggs
• Functions
– Hair, skin, and nails
– General metabolic functions
• High-energy bond
• Transfer energy
– Vitamin structure
– Collagen structure
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17
Key Concepts
• A mixed diet of varied foods and adequate energy
value is the best source of the minerals necessary
for health.
• Of the total amount of minerals a person
consumes, only a relatively limited amount is
bioavailable to the body.
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18
Trace Elements
•
•
•
•
•
•
Iron
Iodine
Zinc
Selenium
Fluoride
Copper
•
•
•
•
•
•
•
Manganese
Chromium
Molybdenum
Cobalt
Boron
Vanadium
Nickel
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19
Iron
– Functions
• Hemoglobin synthesis
– Deficiency states
• Anemia
– Toxicity symptoms
• Hemochromatosis
– Food sources
• Heme (rapid) – 40 % animal foods
• Nonheme (slow)– 60% animal and all plants
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20
Iodine
• Functions
– Participation in thyroid gland’s synthesis of thyroxine
• Deficiency states
– Goiter – usually a lack of iodine causes this
– Cretinism – hypothyroid of childhood
– Hypothyroidism
– Hyperthyroidism
• Food sources
– Iodized table salt, seafood; depends on soil content
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21
Goiter
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22
Zinc
• Functions
– Enzyme constituent
– Immune system
– Protects RBC from damage
• Deficiency states
– Poor wound healing
– Impaired taste and smell
– Iron inhibits absorption
• Food sources
– Meat, seafood, legumes, whole grains
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23
Selenium
• Functions
– Part of antioxidants
• Deficiency affects immune system
• Toxicity symptoms – brittle hair and nails
• Food sources
– Seafood, kidney, liver; depends on soil content
where plants are grown
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24
Other Trace Elements
• Fluoride
– Functions by preventing dental caries
– Exceeding UL may cause fluorosis
• Copper : “Iron twin” (works the same way)
• Manganese
– Inhalation toxicity
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25
Other Trace Elements, cont’d
• Chromium
– Glucose tolerance factor
• Molybdenum
– Inadequate dietary intake improbable
• Other essential trace elements
– Aluminum, arsenic, boron, nickel, silicon, tin,
vanadium
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26
Mineral Supplementation
• Life cycle needs
– Pregnancy and lactation
– Adolescence
– Adulthood
• Clinical needs
– Iron-deficiency - anemia
– Zinc deficiency – immune system weakens
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27
Summary
• Minerals are single, inorganic elements that are
classified according to their relative amounts in
the body.
• Major minerals make up 60% to 80% of all
inorganic material in the body.
• Trace elements make up less than 1% of the
body’s inorganic material.
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28
Key Concepts of Water
Balance
• Water compartments inside and outside cells
maintain a balanced distribution of total body
water via osmosis and diffusion.
• The concentration of various solute particles in
water determines internal shifts and movement of
water.
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29
Homeostasis
• Body’s state of dynamic balance
• Capacity of the body to maintain life systems
despite what enters the system from outside
• Homeostatic mechanisms protect the body’s water
supply
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30
Body Water Functions
• Solvent
– Water is the basic liquid solvent for all
chemical processes within the body
• Transport
– Nutrients carried through the body in waterbased fluids (e.g., blood, secretions)
• Thermoregulation
– Maintains stable body temperature
• Body lubricant – serous and synovial fluids
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31
Body Water Requirements
• Surrounding environment
– Body water evaporates as sweat and must be
replaced
• Activity level
– More water is needed for increased metabolic
demand during physical activity
• Functional losses
– Disease process affects water requirements
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32
Fluid Compartments
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33
Other Dietary Factors
• Dehydration
– >2% total body weight loss
– Special concern in the elderly
• Water intoxication
– Those at risk:
• Infants
• Psychiatric patients
• Patients on psychotropic drugs
• Endurance athletes
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34
Percentage of Body Weight
Loss
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35
Body Water Amount and
Distribution
• Extracellular fluid
– Total body water outside cells
– One quarter of extracellular fluid is blood
plasma
– Three quarters is water surrounding cells and
bathing tissues, water in dense tissue, and water
moving through the body as secretions
– Interstitial fluid
• Fluid surrounding cells in tissues
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36
Body Water Amount and
Distribution, cont’d
• Intracellular fluid
– Total body water inside the cells
– Twice the volume of that outside the cells
• Overall water balance
– Average adult metabolizes 2.5 to 3 L of water/day
– 100 ounces per day
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37
Distribution of Total Body
Water
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38
Electrolytes
• Small, inorganic elements that break apart in a
solution and carry an electrical charge (ions)
• Balance between cation and anion concentration
maintains chemical neutrality necessary for life
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39
Plasma Proteins
•
•
•
•
•
Mainly albumin and globulin
Organic compounds of large molecular size
Retained in blood vessels, does not diffuse out
Controls water movement
Colloids guard blood volume (colloidal osmotic
pressure)
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40
Separating Membranes
• Capillary membrane
– Thin and porous
– Water molecules move freely across them
• Cell membrane
– Thicker membranes
– Constructed to protect and nourish cell contents
– Uses channels for ions and fats merge freely
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41
Moving Water and Solutes
Across Membranes
• Filtration
– Water is forced through membrane pores when
pressure outside the membrane is different
• Active transport
– Necessary to carry particles “upstream” across
separating membranes
• Pinocytosis
– Larger molecules attach to thicker cell membrane,
then are engulfed by cell
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42
Capillary Fluid Shift
Mechanism
• Cells’ water and nutrients must move from
capillaries to cells.
• Water and cell metabolites must return to
capillaries.
• Uses opposing fluid pressures:
– Hydrostatic pressure
– Colloidal osmotic pressure
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43
Organ Systems Involved in
Body Water Balance
• Gastrointestinal circulation
– Water from blood plasma is continually secreted into
the gastrointestinal tract.
– In the latter portion of the intestine, most water and
electrolytes are reabsorbed into the blood.
• Renal circulation
– Kidney filters the blood to maintain water balance and
proper solution of blood
• Hormonal controls:
– Antidiuretic hormone mechanism
– Aldosterone mechanism
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44
Acids and Bases
• Homeostatic balance of acidity or alkalinity must
be maintained in body water solutions and
secretions
• The concentration of hydrogen ions determines the
acidity level
• Acidity expressed in terms of pH
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45
Acid-Base Buffer System
• Handles an excess of acid or base
• Mixture of acid and base that protects a solution from
wide variations in pH
• Main buffer system: carbonic acid/base bicarbonate
(seen in the chloride shift during CO2 transport)
• Respiratory control
– Carbon dioxide leaves the body
• Urinary control
– Kidney monitors hydrogen ions
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46
Summary
• Overall water balance is maintained by fluid
intake and output
• Two types of solute particles control the
distribution of body water
– Electrolytes
– Plasma protein
• The acid-base buffer system uses electrolytes and
hydrogen ions to maintain a normal extracellular
fluid pH of approximately 7.4
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47
• Questions?
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48