Nutrition test 5

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Nutrition test 5
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2010-05-06 02:58:57
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  1. Body Fluids Defined
    • Composed of molecules that
    • move past one another freely

    • Characterized by its ability
    • to conform to the shape of the container that holds it

    • About 50-70% of healthy
    • adult body weight
  2. Body Fluids
    • n The body fluid composition
    • of tissue varies by

    q Tissue type: lean tissues have higher fluid content than fat tissues

    • q Gender
    • : males have more lean tissue and therefore more body fluid

    • q Age:
    • lean tissue is lost with age and body fluid is lost with it
  3. Body Fluids
    n Intracelluar Fluid (ICF)

    • q Within the cell – 2/3 of
    • body fluid

    n Extracellular Fluid (ECF)

    • q Outside the cell – 1/3 of
    • body fluid

    q Interstitial fluid flows between cells that make up a particular tissue or organ

    q Intravascular fluid is the water in the blood and lymph

    • q Plasma
    • transports blood cells within arteries, veins, and capillaries
  4. Electrolytes
    • n Substance that disassociates
    • in solution into electrically charged particles ions

    q Positive charge (cation): sodium, potassium

    q Negative charge (anion): chloride, phosphorus

    n Predominant electrolytes

    q Extracellular fluid (ECF): sodium, chloride

    q Intracellular fluid (ICF): potassium, phosphorus
  5. Body Fluids

    Body Fluids

    Body Fluids

    Functions of Body Fluids
    • n Fluids dissolve and transport
    • substances

    • q Water is an excellent solvent
    • because it dissolves a variety of substances

    • q Blood plasma transport
    • solutes in the body

    • q Water soluble substances: amino acids, glucose, vitamins, minerals,
    • medications

    q Fat soluble substances must be attached to or surrounded by water soluble proteins
  6. Functions of Body Fluids
    n Fluids account for blood volume

    • q Appropriate fluid levels is
    • essential for maintaining healthful blood volume

    q Blood pressure increases when blood volume rises

    q High blood pressure (hypertension) is a risk factor for heart disease and stroke

    q Kidneys help to regulate blood volume and blood pressure
  7. Regulation of Blood Volume

    Functions of Body Fluids
    • n Fluids help maintain body
    • temperature

    • q Body temperature must be
    • within a safe range

    • q High heat capacity of water
    • means that the temperature of our body fluids remains stable

    • q Sweating releases heat as
    • the evaporation of water from the skin cools the skin and blood
  8. Functions of Body Fluids
    • n Protect and Lubricate
    • Tissues

    • q Cerebrospinal fluid protects
    • the brain and spinal cord

    • q Amniotic fluid protects the
    • fetus

    • q Synovial fluid lubricates
    • joints

    • q Digestive juice (saliva)
    • moistens food for ease of swallowing and transport
  9. Functions of Electrolytes
    • n Electrolytes help regulate
    • fluid balance

    • q ‘Water follows ion
    • concentration’. Water follows the movement of electrolytes, moving by osmosis
    • to areas where the concentration of electrolytes is high.

    • q This allows for the controlled
    • movement of fluids into and out of cells.

    • q Osmotic pressure keeps electrolytes in
    • solution from drawing liquid toward them across a semi-permeable membrane
  10. Fluid and Electrolyte
    Balance

    Functions of Electrolytes
    • n Electrolytes enable nerves
    • to respond to stimuli

    • q Movement of Na+
    • and K+ across the membranes of nerve cells changes the electrical
    • charge across the membrane

    • q This change in electrical
    • charge carries the nerve impulse along the nerve cell.
  11. Functions of Electrolytes
    • n Electrolytes signal muscles
    • to contract

    • q Influx of calcium into the
    • muscle from the extracellular space stimulates contraction

    • q Muscles can relax after
    • contraction once the electrical signal is complete and calcium is pumped out of
    • the muscle cell
  12. Fluid Balance
    • n Thirst mechanism
    • (hypothalamus) prompts us to drink when it is stimulated by

    • q Increased concentration of
    • salt and other dissolved substances in the blood

    • q A reduction in blood volume
    • and blood pressure, such as during profuse sweating, vomiting, diarrhea, low
    • fluid intake

    • q Dryness in mouth and throat
    • with low saliva

    • n ADH signals the kidneys to
    • retain water
  13. Water
    n Water

    q Essential for life

    • q Required for fluid and
    • electrolyte balance and many metabolic reactions

    n Recommended intake

    • q DRI: 2.7 liters for the
    • adult female, 3.7 liters for the adult male

    • q Varies with age, body size,
    • health status, physical activity level, environment
  14. Water Guidelines
    n No RDA

    n 1 ml/1kcal

    q »8 cups/d

    n 30 - 55ml/kg

    n Infants have higher needs

    • n Supplied by liquids, foods,
    • metabolism

    • Are You Drinking
    • Enough Water?
  15. Water Balance
    n Dehydration

    • q Insufficient H20
    • intake

    q Athletes, children, elderly

    q Dry, loose skin

    q Concentrated urine

    q Labs

    n Alb ­

    n Na+ ­

    n Glu ­






    n Fluid Overload (toxicity)

    • q Too much water without
    • sufficient electrolytes

    q Kidneys not able to handle

    • q Headaches, blurred vision,
    • cramps, convulsions

    q Labs

    n Alb ¯

    • n
    • Na+ ¯

    n Glu ¯
  16. Sodium Na+

    n
    FUNCTIONS
    q Major cation of the ECF

    q Water balance

    q Nerve functions

    • q Associated with BP & pH
    • balance

    • q Assists with transport of
    • glucose into body cells





    • q Preservative –
    • canned/package foods

    q Processed foods

    • q White bread, rolls, hot
    • dogs, lunch meats, cheese, condiments

    q Table salt





    Hyponatremia

    q Muscle cramps

    q Nausea

    q Vomiting

    q Dizziness

    q Over hydration

    q Confusion

    • n
    • TOXICITY

    Hypernatemia

    q High blood pressure HTN

    q Dehydration
  17. Potassium K+
    Potassium K+

    n FUNCTIONS

    q Major cation of the ICF

    • q Fluid & electrolyte
    • balance

    • q Nerve impulse ; muscle
    • contraction

    n FOODS

    q Fruits & vegetables

    q Meats, milk

    q Legumes

    • q Many salt substitutes are
    • made from potassium chloride



    Potassium K+

    • n
    • DEFICIENCY

    Hyperkalemia

    q Irregular heart beat

    q Loss of appetite

    q Muscle cramps

    • q Can occur in people with
    • kidney disease

    q Avoid salt substitutes

    • n
    • TOXICITY

    Hypokalemia

    q Leads to heart failure

    • q Seen in patients with kidney
    • disease or diabetic ketoacidosis

    • q Caution with certain
    • diuretic meds
  18. Chloride Cl-
    Chloride Cl-

    n FUNCTIONS

    • q Major anion of the ECF –
    • maintain fluid balance

    • q Helps maintain gastric
    • acidity – HCl

    q Nerve transmission

    n FOODS

    • q
    • Salt = Na+Cl-

    q Processed foods

    Chloride Cl-

    • n
    • DEFICIENCY

    q Rare in adults

    • q Can occur in people with
    • eating disorders

    q Convulsion in children

    • n
    • TOXICITY

    • q High blood pressure in salt
    • sensitive individuals
  19. Phosphorus P
    Phosphorus P

    • n
    • FUNCTIONS

    q Major ion of the ICF

    • q Acid/Base balance; fluid
    • balance

    • q Required for bone and tooth
    • strength

    • q Part of various metabolic
    • compounds - ATP

    • n
    • FOODS

    • q Protein rich foods; Dairy
    • products, Meats, Eggs

    q Soft drinks

    • q More readily absorbed from
    • animal sources

    • q Phytic acid prevents
    • absorption from plant sources



    Phosphorus

    n Deficiency: Rare

    n Toxicity:

    • n Causes: kidney disease,
    • excessive vitamin D supplementation or phosphorus-based antacids

    • n S/S muscle spasms &
    • convulsions
  20. Medical Disorders
    • n Disorders related to fluid
    • and electrolyte imbalance include:

    q Dehydration

    q Heat stroke

    q Water intoxication

    q Hypertension

    q Neuropsychiatric disorders

    q Muscle disorders
  21. Dehydration
    Dehydration

    • n Dehydration occurs when
    • water loss exceeds water intake

    • n Commonly due to heavy
    • exercise or high environmental temperatures

    • n Infants and the elderly are
    • more at risk
  22. Heat Stroke
    • n Heat stroke occurs if the
    • body’s temperature regulation mechanisms fail

    • q Occurs in hot, humid
    • environments

    • q Symptoms include rapid
    • pulse, hot, dry skin, high body temp, loss of consciousness

    • q Has been fatal for athletes
    • during exercise in extreme heat

    • q Stop exercising when feeling
    • dizzy, light-headed, disoriented, or nauseated
  23. Hypertension
    • n Hypertension is a chronic
    • condition characterized by high blood pressure.

    • q Systolic pressure over 140mm
    • Hg

    • q Diastolic pressure over 90mm
    • Hg

    • q May not show symptoms -
    • “silent”

    • q Increases a person’s risk of
    • heart disease, stroke, kidney disease





    Hypertension

    n What causes hypertension?

    • q
    • The cause of 95% of hypertension cases is unknown – primary or
    • essential hypertension

    • q
    • 5% are caused by kidney disease, sleep apnea, and salt sensitivity

    • q Recommendations for reducing
    • hypertension: weight loss, increased physical activity, reduced sodium intake,
    • and more whole grains, fruits, vegetables, and low-fat protein sources, DASH
    • diet
  24. Neuropsychiatric and Muscle
    Disorders
    • n
    • Electrolyte imbalances can result in seizures or muscle
    • cramps

    • n Electrolyte imbalances cause
    • changes in nervous system function and impair cognition

    • n Nervous system changes can
    • alter proper muscle function
  25. What
    are Antioxidants?
    • n Compounds that protect cells
    • from the damage caused by oxidation



    • n Nutrients with antioxidant
    • properties:

    q Vitamin E

    q Vitamin C

    • q Vitamin A (precursor,
    • beta-carotene)

    q Selenium
  26. Structure of Atoms
    • n The atom is the smallest
    • unit of matter

    n Atoms are composed of

    • q Nucleus – positive charged
    • center

    q Electrons – negative charged

    particles that surround the nucleus
  27. Transfer of Electrons
    • n Molecules are composed of
    • atoms

    • n During metabolic reactions,
    • electrons can be transferred

    q from the atoms of one molecule

    • q to the atoms of another
    • molecule
  28. Exchange Reactions
    • n Oxidation is a chemical reaction in
    • which atoms lose electrons

    • n Reduction occurs when atoms gain a
    • electron
  29. Free Radicals
    • n Stable atoms have an even
    • number of electrons (pairs) in the outer orbit

    • n Electron loss during
    • oxidation leaves an odd number or unpaired electron

    • n Such highly unstable atoms
    • are called free radicals

    • n Oxygen molecule that becomes
    • a free radical is called reactive oxygen species (ROS)

    • What Causes Free Radicals to
    • Form?

    n Many metabolic processes

    • q Digestion and absorption of
    • food

    • q Immune system fighting
    • infections

    n Environmental factors

    q Pollution

    q Excess sunlight

    q Toxic substances

    q Tobacco smoke

    q Asbestos

    Cell Damage *

    • n Free radicals form within
    • the phospholipid bilayers of cell membranes

    • q Damaged lipid molecules are
    • unable to maintain the integrity of the cell membrane

    • Diseases Linked with Free
    • Radicals

    n Various cancers

    n Heart disease

    n Diabetes

    n Arthritis

    n Cataracts

    n Kidney disease

    n Alzheimer disease

    n Parkinson disease
  30. How
    do Antioxidants Work?
    • n Antioxidants stabilize free
    • radicals and repair the damage they cause

    • n Antioxidant vitamins donate their electrons or
    • hydrogen molecules to free radicals to stabilize them and reduce oxidation
    • damage

    • n Antioxidant minerals function within the enzyme
    • systems that convert free radicals to less damaging substances that can be
    • excreted

    • How do Antioxidants
    • Work? *

    • How do Antioxidants
    • Work?

    • n Other compounds help stabilize
    • free radicals and prevent damage to cells and tissues:

    q Beta-carotene

    q Phytochemicals

    • n Nutrients with antioxidant
    • properties:

    q Vitamin E

    q Vitamin C

    • q Vitamin A ( precursor,
    • beta-carotene)

    q Selenium
  31. Vitamin E (fat-soluble)
    n Functions:

    • n Primary Function is to
    • protect lipids from Free Radicals:
    • PUFAs, Cell membranes, LDL oxidation

    • n Normal nerve & Muscle
    • development

    n Enhances immune system

    n Improves Vit A absorption

    Vitamin E

    n Food Sources:

    • q Vegetable oils (Safflower,
    • sunflower, canola, soybean)

    q Nuts, seeds

    q Wheat germ, soybeans

    • n Vitamin E is destroyed by
    • exposure to oxygen, metals, ultraviolet light, and heat

    • q Little vitamin E in
    • deep-fried and processed foods

    • Vitamin E, too much or not
    • enough?

    n Toxicity uncommon

    • n Interacts with
    • anticoagulants (aspirin, Coumadin)

    • n High doses associated with
    • excessive bleeding, and possibly hemorrhagic stroke

    • n True deficiency
    • is uncommon

    • n s/s hemolytic anemia, loss
    • of muscle coordination & reflexes

    n Anemia in premature infants

    n In adults, caused by fat malabsorption diseases/conditions
  32. Vitamin C (H2O soluble)
    n Functions:

    • q Synthesizes collagen
    • (prevents scurvy)

    q Enhances immune response

    • q Assists synthesis of DNA,
    • Serotonin, Bile

    q Helps regulate hormones

    q Enhances iron absorption

    • q Acts as an antioxidant:
    • protects LDL cholesterol, the lungs, white blood cells, and the stomach



    Vitamin C

    Food Sources:

    n Fresh fruits & veggies

    • n Destroyed by heat &
    • oxygen

    n Can be leached into water

    n Minimize loss by:

    n steaming, microwaving & stir-frying

    • Vitamin C, too much or not
    • enough?

    n Deficiency:

    • n Scurvy: s/s bleeding gums,
    • loose teeth, weakness, wounds fail to heal; anemia

    • n At risk: people who eat few
    • fruits & veggies; people who abuse drugs & alcohol

    n Toxicity: Rare d/t water soluble – excreted in kidneys.

    n Only with supplements

    n MEGADOSE: 10 X RDA over long time; can cause: nausea, diarrhea, nosebleeds.

    n Caution with hemochromatosis
  33. Beta Carotene
    • Provitamin – an inactive form or
    • precursor, of the vitamin that must be converted to its active formof vitamin A

    • Carotenoid, a
    • plant pigment

    • Precursor - one of
    • three carotenoids that can be converted to retinol



    Functions of Beta Carotene

    n Weak antioxidant

    • n Effective against lipid
    • oxidation in cell membranes

    n Enhance immune system

    • n Protect skin from UV light
    • damage

    • n Protect eyes from damage,
    • preventing or delaying age-related vision impairment



    • Beta Carotene, too much or
    • not enough?

    • n Food Sources: Colorful fruits & veggies – red, orange,
    • yellow or deep green

    • n Toxicity: Not toxic but excess can turn the skin yellow
    • or orange



    n Deficiency: None known

    • n Heating foods improves
    • absorption of beta carotene
  34. Vitamin A (fat
    soluble)
    Functions:

    n Antioxidant

    n Essential for proper vision

    • n Cell differentiation –
    • process by which stem cells mature into specialized cells

    n Sperm production & fertilization

    n Bone growth

    • n Derivatives of vitamin A are
    • used to treat acne



    Vitamin A

    n Food sources:

    • q animal (liver, eggs,
    • whole-fat dairy, fortified foods)

    • q plants (red, orange, yellow,
    • and deep-green fruits and vegetables that are high in beta carotene can be
    • converted to vitamin A)

    • Vitamin A, too much or not
    • enough?

    • n Highly toxic at 3–4 times RDA, mainly
    • from supplements

    q Birth defects

    q Damage to liver and eyes

    • q Symptoms: loss of appetite,
    • blurred vision, hair loss, skin disorders

    • n
    • Deficiency

    • q night blindness, xerophthalmia an irreversible
    • blindness hyperkeratosis

    q impaired immunity, growth
  35. Selenium
    – Se (trace mineral)
    n Functions:

    • n Antioxidant; part of an
    • enzyme system

    • n Decreases free radicals,
    • sparing vit E

    • n Needed for thyroxine
    • production – thyroid hormone

    n Food Sources: organ meats, pork, seafood, nuts, wheat, rice

    • n Variable in plant foods d/t
    • different soil conditions



    • Selenium (Se) too much or
    • not enough?

    n Toxicity can occur from supplements

    • q Brittle hair, nails, skin
    • rashes, vomiting, nauseas, weakness, cirrhosis of the liver

    n Deficiency associated with

    • q Keshan disease, a heart
    • disease

    • q Kashin-Beck disease, a
    • deforming arthritis

    q Impaired immunity
  36. Additional Antioxidants
    • n Cofactor – a compound needed for
    • proper enzyme function

    • n These minerals play critical
    • roles in blood health and energy metabolism:

    • q Copper (Cu), zinc (Zn), and
    • manganese (Mn)
    • are part of the superoxide dismutase enzyme antioxidant complex

    • q Iron (Fe) is part of the catalase
    • structure
  37. Cancer
    • n Cancer is a group of
    • diseases characterized by cells growing “out of control”

    • n Primary steps of cancer
    • development:

    q Initiation

    q Promotion

    q Progression

    Cancer Risk

    n Risk factors

    q Tobacco use

    q Sun exposure (UV light)

    q Nutrition

    • q Environmental/occupational
    • exposures

    • q Low levels of physical
    • activity

    • n Antioxidants reduce cancer
    • risk by

    q Enhancing immune system

    q Inhibit cancer cell growth

    • q Prevent oxidative damage to
    • cells
  38. Phytochemicals
    • n Naturally occurring
    • chemicals in plants

    • n May reduce risk for cancer,
    • heart disease

    • n Include phytoestrogen,
    • lycopene, and flavonoids

    • n Found in whole grains,
    • fruits, vegetables, legumes, nuts, garlic, and soy products
  39. Cardiovascular Disease (CVD)
    • n Leading cause of death among
    • adults in USA

    • n Includes all diseases of the
    • heart and blood vessels

    q Coronary heart disease

    • q Hypertension (high blood
    • pressure)

    • q Atherosclerosis (hardening
    • of the arteries)

    • n Primary manifestations of
    • CVD:

    q Heart attack

    q Stroke
  40. Major Risk Factors for CVD
    n Smoking

    n Hypertension

    • n High blood levels of low
    • density lipoprotein (LDL) cholesterol

    n Obesity

    n Sedentary lifestyle

    Other Risk Factors for CVD

    • n Low blood levels of high
    • density lipoprotein (HDL) cholesterol

    • n Impaired glucose tolerance
    • or diabetes

    n Family history of CVD

    q males before age 55

    q females before age 65

    • n Being male older than 45
    • years

    • n Being postmenopausal in
    • women
  41. Low-grade Inflammation
    More important than elevated cholesterol?
    • n Weakens plaque, makes it
    • more fragile

    • q Likely to burst, break away
    • from lining, lodge in blood vessels of heart or brain, and close off blood
    • supply resulting in a heart attack or stroke

    n C-reactive protein (CRP)

    • q Marker for inflammation
    • (laboratory blood test)

    • q Associated with high risk
    • for heart attack in the presence of normal cholesterol levels

    • q High CRP + high cholesterol
    • = high risk for heart attack
  42. Antioxidants and CVD
    • n Antioxidants (vitamins E and
    • lycopene) reduce damage to blood vessels by

    q Scavenging free radicals

    • q Reducing low-grade
    • inflammation

    • q Reducing blood coagulation
    • and clot formation

    • n In fruits, vegetables, and
    • whole grains

    • q Dietary fiber (soluble) -
    • oatmeal and oat bran

    • q Folate - reduce
    • homocysteine, a risk factor for CVD

    q Others (flavonoids)
  43. Aging Process
    • n Associated with increased
    • oxidative damage and reduced activity of antioxidant enzymes in most body
    • tissues

    • n Digestion, absorption, and
    • metabolism of nutrients are impaired with age

    • n What is the optimal
    • antioxidant intake for older adults?

    Vision Impairment

    • n Diseases associated with
    • aging

    n Macular degeneration

    q Leading cause of blindness

    • q Deterioration of center
    • portion of retina

    • q Marked by loss or distortion
    • of central vision

    n Cataract

    • q Damaged portion of eye’s
    • lens causing cloudy vision
  44. Macular Degeneration

    Antioxidants and Vision
    Impairment
    • n Possible role of
    • antioxidants in vision impairment

    • q Lack of nutrients (including
    • antioxidants)

    • q Free-radical damage caused
    • by exposure to oxygen, UV light, and x-rays

    • q Inflammation from eye
    • disease

    • n Current research does not
    • support the use of antioxidant supplements in reversing or delaying aging

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