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Fat soluble vitamins

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One of the first signs of Vitamin A deficiency ... Vitamin D deficiency. Rickets ... Vitamin D and the elderly. Deficiencies more likely to develop in elderly ... – PowerPoint PPT presentation

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Title: Fat soluble vitamins


1
Fat soluble vitamins
  • A,D,E, and K

2
Overview
  • Require bile for absorption
  • Enter lymph then blood along with large products
    of fat digestion
  • Excesses stored in liver and adipose tissue
    retrieved as needed
  • Do not have to be eaten daily
  • Because of storage, average daily intakes are
    recommended
  • Not readily excreted
  • Risk of toxicity greater than with water soluble
    vitamin

3
2 Sources and 3 forms of vitamin A
In food retinyl esters
Beta-carotene from animal
foods from plants In the body retinol
retinal
retinoic acid (supports
(participates (regulates
reproduction)
in vision) growth)
4
Vitamin A and vision
  • Retinal helps maintain cornea
  • Is part of pigment of retina that responds to
    light
  • Some retinal converts irreversibly to retinoic
    acid which is inactive in the eye, and is lost…
  • Retinal must be replenished

5
Vitamin A and protein synthesis and cell
differentiation
  • Needed for differentiation of tissues that cover
    the surface of the body and line interior spaces
    (epithelial tissues) and associated mucus glands
    (goblet cells)
  • Role in differentiation may explain cancer
    preventing properties of Vitamin A

6
Vitamin A and reproduction and growth
  • In men
  • Retinol participates in sperm development
  • In women
  • Supports normal fetal development
  • In children
  • Necessary for growth

7
Vitamin A and bone remodeling
  • Remodeling complex phenomena involved in bone
    growth
  • Small bone converts into larger bone as parts of
    small bone are dismantled and replaced
  • Vitamin A participates in dismantling by aiding
    enzymes that degrade bone

8
Remodeling in the adult
  • Phenomena continues as bone maintenance

9
Antioxidant properties of beta carotene
  • The small amount of beta carotene that does not
    convert into vitamin A acts as an antioxidant and
    protects the body against a variety of diseases

10
Vitamin A deficiencies
  • Do not appear until stores have been depleted
  • Rare in U.S.
  • More common in undeveloped countries

11
Vitamin A deficiency and Infectious disease
susceptibility
  • Measles, pneumonia and diarrhea
  • Potentially fatal
  • Severity correlates with degree of deficiency
  • Large problem in developing countries

12
Night blindness
  • One of the first signs of Vitamin A deficiency
  • Due to lack of retinal in retina, which is
    located in the back of the eye

13
Blindness (xeropthalmia)
  • Total blindness due to lack of vitamin A in
    cornea, which is located in the front of the eye

14
Epithelial cells
  • Epithelial cells of skin become hard because of
    extra keratin deposits
  • Goblet cells in GI tract do not secrete enough
    mucus
  • Other epithelial cell weaken and become
    susceptible to infection

15
Toxicity of Vitamin A
  • Children are most vulnerable to high levels
  • Beta carotene excess from food do not contribute
    to toxicity
  • Conversion to Vitamin A is inefficient
  • Excesses are stored in skin
  • Give skin a yellowish hue
  • Beta carotene excesses from supplements can
    contribute to toxicity
  • Acts as prooxidant
  • Promotes cell division and destruction of vitamin
    A
  • Effects are most evident in people who drink
    alcohol and smoke cigarretes

16
Toxicity and bone defects
  • Excessive intake may weaken bones
  • Recent research suggest most people do not need
    supplement, and even levels in common
    multivitamins may be excessive

17
Toxicity and birth defects
  • High intakes before 7th week are most damaging
  • Can cause abnormal fetal development and birth
    defects (teratogenic effect)

18
Vitamin A and acne
  • All forms of naturally occurring vitamin A are
    ineffective in treating acne
  • Accutane, prescription oral medication, is made
    from vitamin A and used to treat cystic acne
  • Patients must use birth control
  • Highly toxic to fetus
  • Retin-A, prescription topical medication, also
    made from vitamin A
  • Effective against acne, wrinkles and other skin
    conditions
  • Smoothes, softens, lightens skin
  • Causes redness and peeling of skin

19
Vitamin A recommendations
  • Measured in retinol activity equivalents (RAE)
  • 1 microgram of retinol1RAE
  • 12 micrograms of dietary beta carotene1RAE
  • Men
  • 900 micrograms of RAE/day
  • Women
  • 700 micrograms of RAE/day

20
Upper level
  • 3000 micrograms/day

21
Significant sources
  • Retinol
  • Fortified milk and dairy products and margarine
  • Eggs
  • Liver
  • Beta carotene
  • Spinach and other dark leafy green
  • Broccoli
  • Deep orange fruits and vegetables

22
Vitamin D the sunshine vitamin
  • Also known as calciferol or calcitriol
  • Not an essential nutrient
  • Body can synthesize it with exposure to UV in
    sunlight to form its precursor D3
  • D3 is made from cholesterol
  • Precursors are also found in some foods
  • D3 is first modified by the liver, then by the
    kidneys into the active form

23
Roles in the body
  • Acts as a hormone, not a vitamin
  • Chemical messenger

24
Vitamin D and bones
  • Works in concert with vitamins A,C, and K other
    hormones, collagen, calcium, phosphorus,
    magnesium and fluoride in bone making and
    maintenance
  • Helps maintain adequate levels of blood calcium
    and phosphorus needed for bone formation
  • Enhances absorption from GI tract
  • Enhances reabsorption of calcium and phosphorus
    from kidneys, so they are not lost in urine
  • Enhances their mobilization from bone into blood

25
Other functions
  • Affects many other cells
  • Immune system
  • Brain and other parts of nervous system
  • Pancreas
  • Skin
  • Muscles
  • Cartilage
  • Reproductive organs
  • Role in protection against some diseases
  • TB
  • Gum inflammation
  • Multiple sclerosis
  • Some cancers

26
Vitamin D deficiency
  • Rickets
  • Inadequate mineralization of bones in children
    usually caused by vit.D deficiency
  • Bowed legs or knock knees, outward bowed chest,
    knobs on ribs

27
  • Osteomalacia
  • Usually in adult women
  • Bones are soft, flexible, brittle, deformed
  • Bent spine and bowed legs

28
  • Osteoporosis
  • Reduced bone density leading to fractures

29
Vitamin D and the elderly
  • Deficiencies more likely to develop in elderly
  • Skin, liver and kidneys are not as efficient
  • Older adults often do not drink milk, which is
    supplemented with vitamin D
  • Often elderly do not get adequate exposure to
    sunlight

30
Vitamin D RDA
  • Adults
  • 5 micrograms/day (19-50)
  • 10 micrograms/day (51-70)
  • 15 micrograms/day (over 70)

31
Upper level
  • Adults
  • 50 micrograms/day

32
Toxicity
  • Hypervitaminosis D
  • Toxicity symptoms
  • Elevated blood calcium
  • Calcifications of soft tissues

33
Significant sources of vitamin D
  • Exposure to sunlight
  • Fortified foods, including milk
  • Veal
  • Beef
  • Egg yolks
  • Liver
  • Fatty fish

34
Vitamin E
  • Other names
  • Alpha tocopherol
  • RDA
  • 15 mg/day
  • Upper level
  • 1000 mg/day
  • Chief functions
  • Antioxidant stabilizes cell membranes,
    regulation of oxidation reactions, protection of
    polyunsaturated fatty acids and vitamin A

35
  • Significant sources
  • Polyunsaturated plant oils
  • Leafy green vegetables
  • Wheat germ
  • Whole grains
  • Liver
  • Eggs yolks
  • Nuts and seeds
  • Fatty meats

36
  • Deficiency symptoms
  • Red blood cell breakage
  • Nerve damage
  • Toxicity symptoms
  • Augments effects of anticlotting medications
    (enhances bleeding)

37
Vitamin K
  • Other names
  • Phylloquinone, menaquinone, menadione,
    naphthoquinone
  • RDA
  • Men 120 micrograms/day
  • Women 90 micrograms/day
  • Upper level
  • None established
  • Chief functions
  • Synthesis of blood clotting proteins and bone
    proteins

38
  • Significant sources
  • Bacterial synthesis in digestive tract
  • Liver
  • Green leafy vegetables
  • Cabbage type vegetables
  • Milk
  • Deficiency symptoms
  • Hemorrhage
  • Toxicity symptoms
  • None known

39
The End
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