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Chapter 7: The Vitamins

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Title: Chapter 7: The Vitamins


1
Chapter 7 The Vitamins
  • Basic Nutrition
  • Dr. Fralinger
  • 10/15/07

2
Introduction
  • Vitamins
  • Organic compounds that are vital to life and
    indispensable to body functions, but are needed
    only in minute amounts
  • Noncaloric essential nutrients
  • Research hints that two of the major scourges of
    humankind, CVD and cancer, may be linked with low
    intakes of vitamins

3
Introduction
  • Geneticists suspect that chronic deficiencies of
    vitamins and minerals may be major contributors
    to genetic damage that can lead to cancer
  • Also suspect that vitamin excesses may do the
    same thing

4
Introduction
  • The only disease a vitamin will cure is the one
    caused by a deficiency of that vitamin
  • Chronic disease prevention evidence still
    emerging

5
Deficiency and classification of vitamins
  • Vitamins are essential, noncaloric nutrients that
    are needed in tiny amounts in the diet and help
    to drive cell processes in the body
  • The fat-soluble vitamins are vitamins A, D, E,
    and K
  • The water-soluble vitamins are vitamin C and the
    B vitamins

6
Deficiency and classification of vitamins
  • Precursors, provitamins
  • Compounds that can be converted into active
    vitamins once inside the body

7
The Fat-Soluble Vitamins
  • Vitamins A, D, E, K
  • Found in the fats and oils of foods
  • Require bile for absorption
  • Once absorbed, they are stored in the liver and
    fatty tissues until the body needs them
  • May be toxic in excess

8
The Fat-Soluble Vitamins
  • Vitamin A
  • First fat-soluble vitamin recognized
  • Beta-carotene the plant-derived precursor
  • Three forms are active in the body
  • Retinol antioxidant
  • Retinal
  • Retinoic acid

9
The Fat-Soluble Vitamins
  • Vitamin A is versatile - has roles in
  • gene expression
  • Vision
  • maintenance of body linings and skin
  • immune defenses
  • growth of bones and body
  • normal development of cells

10
The Fat-Soluble Vitamins
  • Vitamin A
  • Gene expression
  • Help activate or deactivate certain genes and
    affect the production of specific proteins
  • Eyesight
  • Retina light-sensitive nerve cells lining the
    back of the inside of the eye
  • Cornea hard, transparent membrane covering the
    outside of the eye
  • Rhodopsin light-sensitive pigment of the cells
    in the retina contains vitamin A

11
Eyesight continued
  • Night blindness
  • Slow recovery of vision after exposure to flashes
    of bright light at night
  • Early symptom of vitamin a deficiency
  • Keratin
  • Normal protein of hair and nails
  • Keratinization
  • Accumulation of keratin in a tissue sign of vit.
    A deficiency

12
Eyesight contd
  • Xerosis
  • Drying of the cornea symptom of vit. A
    deficiency
  • Xerophthalmia
  • Progressive hardening of the cornea of the eye in
    advanced vit. A deficiency that can lead to
    blindness

13
Fat-Soluble Vitamins
  • Vitamin A
  • Skin and body linings
  • Epithelial tissue
  • Serve as selective barriers to environmental
    factors
  • Cornea, skin, respiratory tract lining, digestive
    tract lining
  • Cell differentiation
  • Process by which immature cells are stimulated to
    mature and gain the ability to perform functions
    characteristic of their cell type

14
Fat-Soluble Vitamins
  • Vitamin A
  • Immunity
  • So many of the bodys defenses against infection
    depend on an adequate supply
  • Growth
  • Assists in growth of bone and teeth
  • Deficiency around the world
  • Between 3 and 10 million of the worlds children
    suffer from signs of severe deficiency

15
Vitamin A toxicity
  • Symptoms include
  • Abdominal pain
  • Hair loss
  • Joint pain
  • Stunted growth
  • Bone and muscle soreness
  • Cessation of menstruation
  • Nausea
  • Diarrhea
  • Rashes
  • Damage to liver
  • Enlargement of spleen

16
Vitamin A recommendations
  • International unit
  • Measure of fat-soluble vitamin activity sometimes
    used on supplement labels
  • Amount needed is proportional to your body weight
  • DRI for man 900 micrograms
  • DRI for woman 700 micrograms

17
Food sources of vitamin A
  • Foods of animal origin
  • Liver
  • Fish oil
  • Milk and milk products
  • Cereals
  • Butter
  • Eggs
  • Vegetables and fruits beta-carotene

18
Vitamin A
  • Beta-carotene is an effective antioxidant in the
    body
  • Brightly colored plant foods are riches in
    beta-carotene diets containing these foods are
    associated with eye health

19
Vitamin A
  • Carotenoid
  • Range in color from light yellow to reddish
    orange
  • Chemical relatives of beta-carotene
  • Retinol activity equivalents (RAE)
  • New measure of vit. A activity of beta-carotene
    and other vit. A precursors
  • Reflects amt of retinol body will derive from a
    food containing vit. A precursor compounds

20
Vitamin A
  • Macular degeneration
  • Common, progressive loss of function of the part
    of the retina that is most crucial to focused
    vision
  • Degeneration often leads to blindness

21
Vitamin A
  • Dietary antioxidants
  • Compounds typically found in plant foods that
    decrease adverse effects of oxidation on living
    tissues
  • Major are vit. E, C, and beta-carotene

22
Vitamin D
  • Raises mineral levels in the blood (calcium
    phosphorus) - bone formation and maintenance
  • Deficiency can cause rickets in childhood or
    osteomalacia in later life
  • Rickets- Abnormal growth of bone
  • Bowed legs or knock-knees
  • Outward-bowed chest
  • Knobs on ribs
  • Osteomalacia overabundance of unmineralized
    bone protein
  • Bending of the spine and bowing of the legs

23
Vitamin D
  • Most toxic of all the vitamins excesses
    dangerous or deadly
  • People exposed to sun make it from a
    cholesterol-like compound in the skin
  • Fortified milk is an important food source

24
Vitamin D
  • Factors affecting sun exposure and vitamin D
    synthesis
  • Air pollution
  • City living
  • Clothing
  • Geography
  • Homebound
  • Season
  • Sunscreen
  • Time of day

25
Vitamin E
  • Acts as an antioxidant in cell membranes
  • Important for integrity of cells exposed to high
    oxygen concentrations (lungs and red white
    blood cells)
  • Deficiency rare in human beings, but does occur
    in newborn premature infants

26
Vitamin E
  • Widely distributed in plant foods
  • Destroyed by high heat
  • Toxicity is rare
  • Free radicals
  • Atoms or molecules with one or more unpaired
    electrons that make it unstable and highly
    reactive

27
Vitamin E
  • USDA food guide recommends small daily intakes of
    oils to supply vitamin E
  • DRI
  • Adults 15 mg/day
  • Erythrocyte hemolysis
  • Rupture of the RBCs caused by deficiency

28
Vitamin K
  • Necessary for blood to clot (Koagulation)
  • Deficiency causes uncontrolled bleeding
  • Produced by bacterial inhabitants of the
    digestive tract
  • Toxicity causes jaundice
  • Yellowing of the skin due to spillover of the
    bile pigment bilirubin from the liver into the
    general circulation

29
Vitamin K
  • DRI
  • Men 120 ug/day
  • Women 90 ug/day

30
Vitamin C
  • Antioxidant
  • Helps to maintain collagen (protein of connective
    tissue
  • Protects against infection
  • Helps in iron absorption
  • Cold or cancer prevention not well supported by
    research
  • Ample amts can be obtained from foods

31
Vitamin C
  • Scurvy
  • Vitamin C-deficiency disease
  • Ascorbic acid
  • One of the active forms of vit. C
  • Collagen
  • Chief protein of most connective tissues,
    including scars, ligaments, tendons, underlying
    matrix of teeth
  • Prooxidant
  • Compound that triggers reactions involving oxygen

32
Vitamin C
  • DRI
  • Men 90 mg/day
  • Women 75 mg/day
  • Smokers - 35 mg/day

33
The B Vitamins in Unison
  • Tender Romance Never Fails with 60 or 12
    Beautiful Pearls
  • Thiamin, Riboflavin, Niacin, Folate, B6 and B12,
    Biotin, Pantothenic acid
  • Act as coenzymes
  • Small molecules that work with enzymes to promote
    their activity

34
B Vitamin Roles in Metabolism
  • Help body metabolize carbs, lipids, and amino
    acids
  • Help the body use the energy-yielding nutrients

35
B Vitamin Deficiencies
  • If they are present, they are not felt
  • Only when they are absent do we feel it
  • Deficiencies lead to

36
B Vitamins
  • As part of coenzymes, help enzymes do their jobs
  • Facilitate the work of every cell
  • Some help generate energy
  • Others help make protein and new cells
  • Work everywhere in the body tissue to metabolize
    carbs, fat and protein

37
B Vitamins as Individuals
  • Thiamin
  • Involved in the bodys use of fuels
  • Beriberi
  • Thiamin-deficiency disease
  • Characterized by
  • loss of sensation in the hands and feet
  • muscular weakness
  • advancing paralysis
  • abnormal heart action

38
B Vitamins as Individuals
  • Riboflavin
  • Active in the bodys energy-releasing mechanisms
  • Niacin
  • Needed in energy metabolism
  • Can be eaten preformed or can be made in body
    tryptophan
  • Pellagra
  • Niacin-deficiency disease
  • Symptoms are the 4 Ds diarrhea, dermatitis,
    dementia, and death

39
B Vitamins as Individuals
  • Niacin equivalents (NE)
  • Amt of niacin present in food, including the
    niacin that can theoretically be made from its
    precursor tryptophan present in the food
  • Folate
  • Acts as part of a coenzyme important in the
    manufacture of new cells
  • Form added to foods and supplements is folic acid

40
B Vitamins as Individuals
  • Neural tube defects
  • Abnormalities of the brain and spinal cord
    apparent at birth
  • believed to be related to womans folate intake
    before and during pregnancy
  • Dietary folate equivalent
  • Unit of measure expressing the amt of folate
    available to the body from naturally occurring
    sources

41
B Vitamins as Individuals
  • Vitamin B12
  • Helps to convert folate to its active form
  • Helps maintain the sheath around nerve cells
  • Intrinsic factor
  • Factor found inside a system
  • Pernicious anemia
  • B12 deficiency disease
  • Caused by lack of intrinsic factor
  • Characterized by large, immature RBC damage to
    the nervous system

42
B Vitamins as Individuals
  • Vitamin B6
  • Needed in protein metabolism
  • Plays roles in synthesis of hemoglobin and
    neurotransmitters
  • Assists in conversion of amino acid tryptophan to
    serotonin
  • Serotonin
  • Important in sleep regulation, appetite control,
    mood regulation

43
B Vitamins as Individuals
  • B6 contd
  • Carpal tunnel syndrome
  • Piched nerve at the wrist, causing pain or
    numbness in the hand
  • Often caused by repetitive motion of the wrist

44
B Vitamins and Heart Disease
  • Homocysteine
  • Amino acid produced as an intermediate compound
    during amino acid metabolism
  • Buildup in blood associated with deficiencies of
    folate other B vitamins - may increase risk of
    disease
  • Biotin
  • Coenzyme necessary for fat synthesis and other
    metabolic reactions
  • Panthothenic acid
  • B vitamin important in energy metabolism

45
Non-B vitamins
  • Choline is needed in the diet, but it is not a
    vitamin and deficiencies are unheard of outside
    the lab.
  • May other substances that people claim are B
    vitamins are not (carnitine, inositol, lipoic
    acid)

46
Non-B vitamins
  • Choline
  • Nonessential nutrient used to make the
    phospholipid lecithin and other molecules
  • Carnitine
  • Nonessential nutrient that functions in cellular
    activities
  • Inositol
  • Nonessential nutrient found in cell membranes
  • Lipoic acid
  • Nonessential nutrient
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