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Chapter 8 Vitamins

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Chapter 8 Vitamins What are Vitamins? Essential organic substances Produce deficiency symptoms when missing from diet Yield no energy Basic functions Facilitate ... – PowerPoint PPT presentation

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Title: Chapter 8 Vitamins


1
Chapter 8Vitamins
2
What are Vitamins?
  • Essential organic substances
  • Produce deficiency symptoms when missing from
    diet
  • Yield no energy
  • Basic functions
  • Facilitate energy-yielding chemical reactions
  • Function as co-enzymes
  • Fat-soluble vitamins
  • Water-soluble vitamins

3
Fun Facts
  • Vitamins were named in order of discovery (A, B,
    C, D, )
  • Other substances found not to be essential were
    dropped (e.g., vitamin P)
  • B-vitamins were thought to be one vitamin
    turned out to be many (e.g., B1, B2, B3,)

4
Vital Dietary Components
  • Megadose (gt3-10x needs as a starting point)
  • Proved useful in treating certain conditions
  • Plant and animal foods provide vitamins
  • Most synthesized vitamins work equally well in
    the body vs natural
  • Scientists believe they have discovered all the
    vitamins

5
Storage of Vitamins in the Body
  • Fat-soluble
  • Not readily excreted (except vitamin K)
  • Water-soluble
  • Generally lost from the body (except vitamins B-6
    and B-12)
  • Excreted via urine
  • Vitamins should be consumed daily
  • Occasional lapse is harmless

6
Vitamin Toxicity
  • Fat-soluble vitamins (e.g. Vitamin A)
  • Can accumulate in the body
  • Water-soluble vitamins
  • Some can cause toxicity
  • Mostly likely due to supplementation

7
Preservation of Vitamins
  • Decreased vitamin content
  • Improper storage
  • Excessive cooking gt40C
  • Exposure to light, heat, air, water, and
    alkalinity
  • Eat foods soon after harvest (EAT FRESH)
  • Freeze foods not consumed within a few days
  • Blanching destroys enzymes (bacteria)
  • Slows down vitamin degradation

8
Preservation Tips
9
Fat-Soluble Vitamins Overview
  • Dissolve in organic solvents
  • Not readily excreted
  • Can cause toxicity
  • Absorbed along with fat
  • Fat malabsorption (Xenical/Olestra)
  • May cause deficiency
  • Cystic fibrosis (Vit. deficiency)
  • Transported with fat
  • In lipoproteins

Olestra
Xenical
10
Confirming your knowledgeWhat are the fat
Soluble vitamins, why (i.e. non polar)?
1
2
3
4
11
Vitamin A
  • Narrow optimal intake range
  • Preformed
  • Retinoids
  • Found in animal products (fish/organ meats)
  • Proformed (proVitamin A)
  • Carotenoids
  • Found in plant products
  • Can be converted to Vit A
  • by the body

B carotene
12
Functions of Vitamin A
  • Promote vision
  • Night blindness
  • Promote growth
  • Prevent drying of the skin and eyes
  • Xerophthalmia (figure 8-1) macular degeneration
  • Promote immune function and resistance to
    bacterial infection
  • Cardiovascular disease prevention (b/c
    antioxidant)
  • Cancer prevention (antioxidants and other)
  • Acne medication (Retin-A, Accutane)

13
Challenge Question
  • What is the name following compound (which has
    been shown to reduce prostate cancer risk) and
    what are good sources?

Gann et al., 1999, Cancer Research, 59, 1225
14
Food Sources of Vitamin A see 8-2
15
Recommended Amounts for Vitamin A
  • 900 ?g RAE for men
  • 700 ?g RAE for women
  • Daily Value is 1000 ?g (RAE) 5000 IU
  • Upper Level is 3000 ?g, 10,000 IU
  • Much stored in the liver
  • No separate RDA for carotenoids

16
Toxicity of Vitamin A
  • Large intake of vitamin A (preformed)
  • Over a long period
  • Use of Accutane and Retin-A 10,000 IU or 3000
    RAE
  • Signs and symptoms
  • Bone/muscle pain, loss of appetite, skin
    disorders, headache, dry skin, hair loss,
    increased liver size, vomiting
  • Fetal malformation (binds to DNA ? cell develop.)
  • Possible permanent damage (infants)
  • lt 3000 IUs/day if pregnant

17
Vitamin D
  • Prohormone
  • Derived from cholesterol
  • Synthesized from sun exposure
  • Sunscreen SPF gt8 decreases synthesis 95
  • Expose hands, face, arms 2-3 x/week for 5-10
    minutes each time (more for darker skin)
  • Insufficient sun exposure makes this a vitamin
  • Activated by enzymes in liver and kidneys
  • Deficiency can cause disease

18
Activation of Vitamin D
19
Functions of Vitamin D
  • Regulates blood calcium
  • Along with the parathyroid hormone
  • Regulates calcium phosphorus absorption
  • Reduces kidney excretion of calcium
  • Regulates calcium deposition in bones
  • Influences normal cell development
  • Linked to reduction of breast, colon, and
    prostate cancer

20
Role in Bone Formation
  • Causes calcium phosphorus to deposit in the
    bones
  • Strengthens bones
  • Rickets is the result of low vitamin D
  • Breastfed infants with little sun exposure
  • Osteomalacia (soft bones)
  • Rickets-like disease in adults
  • Bones lose minerals and become porous

21
Challenge Question
  • According to the USDA and ODS Vitamin D is now
    considered a deficiency in N. American diets
  • what are the two major reasons?
  • 1.
  • 2.

22
Food Sources of Vitamin D
  • Fatty fish (salmon, herring)
  • Fortified milk (N. fat, Low fat or Whole)
  • Some fortified cereal

23
Adequate Intake (AI) for Vitamin D
  • 5 ?g/day (200 IU/day) for adults under age 51
  • 10-15 ?g/day (400 - 600 IU/day) for older adults
  • Supplement if a breastfed infant
  • (See physician for details)

24
Toxicity Warning
  • Vitamin D can be very toxic, especially in
    infancy and childhood
  • Upper Level is 50 µg/day
  • Results in
  • Over-absorption of calcium (hypercalcemia),
    increase calcium excretion
  • Calcium deposits in organs (kidneys) blood
    vessels
  • Growth retardation

25
Vitamin E
  • Fat-soluble antioxidant
  • a ß d gamma tocopherol forms
  • Resides mostly on cell membranes

26
Other Functions of Vitamin E
  • Protects double bonds in unsaturated fats
  • Improves vitamin A absorption
  • Deficiency
  • Breakdown of cell membranes
  • Hemolysis
  • Nerve degeneration
  • RDA for adults is 15 mg/day
  • Many adults are not meeting this goal

27
Food Sources of Vitamin E
28
Toxicity of Vitamin E
  • Upper Level is 1,000 mg/day (supplementary
    alpha-tocopherol)
  • Upper Level is 1500 IU (natural sources) or 1100
    IU (synthetic forms)
  • Adivse mixture of natural tocopherols (vs
    synthetic sources)
  • (400 IUs)
  • Toxic effects
  • Inhibit vitamin K metabolism and anticoagulants
  • Possible hemorrhage
  • Muscle weakness, headaches, nausea

29
Vitamin E
  • SHOW Vit E video

30
Vitamin K (Koagulation)
  • Synthesized by bacteria in the colon (10) and
    absorbed (diet)
  • Frequent anti-biotics ? deficiency. . .
  • Role in coagulation process (fig 8-10)
  • Role in calcium-binding potential

31
Food Sources of Vitamin K
  • Liver
  • Green leafy vegetables
  • Broccoli
  • Peas
  • Green beans
  • Resistant to cooking losses
  • Limited vitamin K stored in the body (lt24hr)

32
Adequate Intake for Vitamin K
  • 90 µg/day for women
  • 120 µg/day for men
  • Excess vitamins A and E
  • Interferes with vitamin K
  • May cause hemorrhage and fractures
  • Newborns
  • Routinely injected with vitamin K
  • Breast milk is a poor source
  • Toxicity unlikely readily excreted
  • High Levels ? CVD, prevent reduced clotting

33
Overview of Water-Soluble Vitamins
  • Dissolve in water
  • Generally readily excreted from body
  • Subject to cooking losses
  • Function as coenzymes
  • Participate in energy metabolism
  • 50-90 of B vitamins are absorbed
  • Marginal deficiency more common
  • U.S. Enrichment Act (grains milled?loose vitamins
    . .)
  • Must be added back (enriched) to products
    (cereals)
  • Why experts recommend whole grains/brown rice vs
  • Refined grain products

34
Confirming your KnowledgeOverview of
Water-Soluble Vitamins
  • What are the water soluble vitamins and why (i.e.
    polar) ?

(4)
(3)
(2)
(1)
(5)
(6)
(9)
(7)
(8)
35
Overview of Water-Soluble Vitamins Participate
in energy metabolism
36
Thiamin
  • Sensitive to alkalinity (base) and heat
  • Coenzyme form used in energy metabolism
  • Deficiency Beriberi (severe muscle weakness
  • RDA
  • 1.1 mg/day for women
  • 1.2 mg/day for men
  • Most exceed RDA in diet
  • Surplus is rapidly lost in urine non-toxic

37
Food Sources of Thiamin, fig. 8-14
38
Riboflavin
  • Coenzyme forms participate in energy-yielding
    metabolic pathways
  • Deficiency
  • Cheilosis, inflammation of mouth and tongue,
    dermatitis, sensitivity to sun
  • RDA
  • 1.1 mg/day for women
  • 1.3 mg/day for men
  • Average intake above RDA
  • Non-toxic

39
Food Sources of Riboflavin
  • Milk/milk products
  • Enriched grains/cereals
  • Eggs
  • Liver
  • Spinach
  • Oysters
  • Brewers yeast

40
Niacin
  • Coenzyme forms used in energy metabolism
  • Deficiency
  • Pellagra rough/painful skin (epidemic US lt
    1930s)
  • Dementia, diarrhea, dermatitis,
  • RDA
  • 14 mg/day for women
  • 16 mg/day for men
  • Toxicity
  • Upper Level is 35 mg/day

41
Food Sources of Niacin
  • Enriched grains (breakfast cereals)
  • Beef
  • Chicken/turkey
  • Fish
  • Heat stable little cooking loss
  • 60 mg tryptophan (Amino acid) can be converted
    into 1 mg niacin

42
Pantothenic Acid
  • Part of Coenzyme-A
  • Essential for metabolism of carbohydrate, fat,
    and protein
  • Deficiency rare
  • Usually in combination with other deficiencies

43
Food Sources of Pantothenic Acid
  • Meat
  • Milk
  • Mushrooms
  • Liver
  • Peanuts
  • Adequate Intake 5 mg/day
  • Average intake meets AI

44
Biotin
  • Free and bound form
  • Co-enzyme
  • Metabolism of carbohydrate and fat
  • Helps breakdown certain amino acids
  • Deficiencyrare
  • Scaly, inflamed skin
  • Changes in tongue, lips
  • Decreased appetite, nausea, vomiting

45
Food Sources of Biotin
  • Cauliflower, egg yolk, liver, peanuts, cheese
  • Intestinal synthesis of biotin contributes very
    little (10)
  • Avidin egg protein inhibits absorption
  • More than a dozen raw egg whites a day to cause
    this effect

46
Biotin Needs
  • Adequate intake is 30 µg/day for adults
  • No Upper Level for biotin
  • Relatively nontoxic

47
Vitamin B-6
  • Coenzyme forms
  • Activate enzymes needed for metabolism of
    carbohydrate, fat, and protein
  • Synthesize nonessential amino acids via
    transamination
  • Synthesize neurotransmitters
  • Synthesize hemoglobin and WBC

48
Food Sources of Vitamin B-6, fig. 8-22
49
RDA for Vitamin B-6
  • 1.3 mg/day for adults
  • 1.7 mg/day for men over 50
  • 1.5 mg/day for women over 50
  • Daily Value set at 2 mg
  • Average intake is more than RDA
  • Athletes may need more
  • Alcohol increases vitamin B-6 destruction

50
Vitamin B-6 As a Medicine?
  • 50-100 mg/day therapy
  • Questionable treatment of PMS
  • May treat pregnancy hypertension
  • Carpal tunnel syndrome
  • Morning sickness
  • (100 mg/day may help see Ch. 13)
  • Toxicity potential
  • gt 200 mg/day can lead to irreversible nerve
    damage
  • Upper Level set at 100 mg/day

51
Folate
  • Coenzyme
  • DNA synthesis
  • Homocysteine metabolism
  • Neurotransmitter formation
  • Sensitive to
  • Heat, oxidation, ultraviolet light

52
Folate Deficiency
  • Megaloblast cells
  • Megaloblastic Anemia
  • 10 N. Americans- genetic defect to process
    folate (req. 2X RDA), need genetic testing. .
  • Neural tube defects
  • Women need ample Folic acid
  • Neural tube closes w/i 28 days of pregnancy ?
    spinal bifuda

53
  • Megaloblast cells
  • -Req. ample Folic acid

54
Child bearing Women need ample Folic acid Neural
tube closes w/i 28 days of pregnancy ? spinal
bifuda
55
Food Sources of Folate
  • Liver
  • Fortified breakfast cereals
  • Grains, legumes
  • Foliage vegetables
  • Orange juice

56
RDA for Folate
  • 400 µg/day for adults
  • 600 µg/day for pregnant women
  • Excess intake can mask vitamin B-12 deficiency
  • Upper Level 1 mg (synthetic form)
  • Synthetic form 1.7 X more potent. . .
  • Folate in food has limited absorption

(synthetic form)
(Natural form)
57
Vitamin B-12
  • Synthesized by bacteria and fungi
  • Coenzyme
  • Role in folate metabolism
  • Maintenance of the myelin sheaths
  • RBC formation
  • Deficiency (absorption problems)
  • Pernicious anemia (weakness, sore tongue, back
    pain)
  • Nerve degeneration and paralysis

58
B-12 Absorption -aging
  • Requires a protein from salivary gland
  • Requires stomach acid (declines w/ age)
  • Requires the intrinsic factor (declines w/ age)
  • Absorbed in the last part of the small intestine
  • About 50 of B-12 is absorbed
  • Vegetarian/Vegan diets low in Vit. B-12
  • (need supplement or specified rich source)

59
Therapy for Ineffective Absorption
  • Many factors can disrupt this process
  • Monthly injections of vitamin B-12
  • Vitamin B-12 nasal gel
  • Megadoses of vitamin B-12
  • Allow for passive diffusion

60
Food Sources of Vitamin B-12
  • Synthesized by bacteria, fungi and algae
  • (Stored primarily in the liver of animals)
  • Animal products
  • Organ meat
  • Seafood
  • Eggs
  • yogurt
  • Milk
  • Corn flakes cereal (w/ soy milk)

61
RDA for Vitamin B-12
  • 2.4 µg/day for adults
  • Over age 50 recommended take synthetic form
  • Not bound to foods (no require low stomach acid)
  • Average intake exceeds RDA
  • B-12 stored in the liver (gt 3 years before
    deficiency)
  • Non-toxic

62
Vitamin C
  • Synthesized by most animals
  • Not by humans
  • Decreased absorption with high intakes gt 250mg
  • Excess excreted
  • Diarrhea common
  • Sensitive to
  • Cooking/heat (high temp) use medium setting
  • Iron, copper, oxygen

63
Functions of Vitamin C
  • Synthesis of collagen (connective tissue)
  • Stretch marks
  • Iron absorption
  • Immune functions
  • Prevents duration of common cold?
  • Interacts with w/ oxidized Vit. E recycles?
  • Anti-cancer agent and cataracts
  • Antioxidant?
  • Req. for syn. Of hormones

64
Challenge QuestionWhat has more Vitamin C/gram
and is the best dietary choice for combating the
common cold and why?
  • 1 medium orange
  • 1 medium red pepper

65
Deficiency of Vitamin C
  • Scurvy
  • Deficient for 20-40 days
  • Fatigue, pinpoint hemorrhages
  • Bleeding gums
  • Weakness
  • Fractures
  • Associated with poverty

66
Food Sources of Vitamin C
  • Citrus fruits
  • Potatoes
  • Green pepper
  • Cauliflower
  • Broccoli
  • Strawberries
  • Romaine lettuce
  • Spinach

67
RDA for Vitamin C
  • 90 mg/day for adult males
  • 75 mg/day for adult females (enhances Fe
    absorptn.)
  • Daily Value is 60 mg
  • 35 mg/day for smokers
  • Average intake 70-100 mg/day
  • Upper Level is 2 g/day (inflammation diarrhea)
  • Better to take low doses (250 mg) more frequent
  • vs MegaDOSE 1 Gram (1000 mg) / day

68
Choline
  • Essential nutrient, though
  • not a vitamin
  • All tissues contain choline
  • Precursor for acetylcholine (neurotransmitter)
  • Precursor for phospholipids

69
Food Sources of Choline
  • Widely distributed in foods
  • Fruits/vegetables
  • Milk
  • Liver
  • Eggs
  • Peanuts
  • Lecithin added to food
  • Deficiency rare

70
Needs for Choline
  • Adequate Intake is 550 mg/day for males
  • Adequate Intake is 425 mg/day for females
  • Average intake is 700-1000 mg/day
  • High doses
  • Associated with fishy body odor, vomiting,
    salivation, sweating, hypotension, GI effects
  • Upper Level is 3.5 grams/day

71
Vitamin-like Compounds
  • Choline
  • Carnitine
  • Inositol
  • Taurine
  • Lipoic acid
  • Synthesized in the body at the expense of amino
    acids and other nutrients

72
Vitamins-SUMMARYFunctions in the Body
With a balanced diet no need for supplements?
73
Dietary Supplements 21 Billion
74
Dietary Supplements Classified as
  • Vitamins
  • Minerals
  • Herbs
  • Amino Acids
  • A dietary substance to supplement the diet
  • Try a case study?

Fe2
75
(No Transcript)
76
Vitamins, Supplements SUMMARY
  • If going to experiment . . .
  • Make sure lt (upper limit) of toxic level
  • Min. 6 weeks for evaluation. . .
  • ANY SUPPLEMENT QUESTIONS? See below
  • Check any of the following 6 websites for
    validity
  • 1. www.acsh.org
  • 2. www.quackwatch.com
  • 3. www.ncahf.org
  • 4. http//dietary-supplements.info.nih.gov
  • 5. www.eatright.org
  • 6. www.usp.org/USPVerified/dietarySupplements/
  • 7. web of science- (use UCSC Lib login,
  • http//oca.ucsc.edu/login (22200-0230485-15)
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