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Vitamins

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Title: Vitamins


1
Chapter 7
  • Vitamins

2
Key Concepts
  • Noncaloric
  • Essential nutrients necessary for many metabolic
    tasks and the prevention of certain diseases
  • Organic substances
  • Needed by body for normal metabolism, growth
    maintenance

3
Key Concepts
  • Vitamins do not provide energy
  • Vitamins work as coenzymes to activate other
    enzymes in the body

4
Discovery Early Observations
  • Discovered while searching for cures for classic
    diseases
  • Dr. James Lind, 1753
  • Sailors dying on long voyages without fresh food
  • Scurvy deficiency vitamin C, causes severe
    bleeding
  • Lemons and limes provided, no one became ill

5
Era of Vitamin Discovery
  • Most vitamins discovered in early 1900s
  • At first scientists assigned letters to each
    vitamin
  • A, C, D, E, K
  • This practice was abandoned in favor of more
    specific names
  • Riboflavin, niacin, thiamine, etc.

6
Definition of Vitamin
  • vital, organic substance
  • only necessary in extremely small amounts.
  • cannot be manufactured by the body in sufficient
    quantities to sustain life
  • Vitamins micronutrients
  • Carb/fat/protein macronutrients

7
Function of Vitamins
  • 1. Metabolism coenzyme needed for metabolism
  • 2. Tissue Bone building
  • 3. Prevention of deficiency diseases
  • Scurvy, beri beri, pellagra

8
VitaminsClasses
  • Fat soluble (vit. A,D,E,K)
  • Best absorbed when eaten with fat
  • May be stored for long periods in liver and
    adipose tissue
  • ie Vit A best absorbed w/ whole milk
  • Water soluble (vit. B,C, folate)
  • Easily absorbed by intestinal cells and
    transported by the portal (liver) circulation
  • Not stored, so must be eaten on regular basis

9
Fat-Soluble VitaminsVitamin A
  • Functions
  • Vision (healthy retina, prevent macular
    degeneration)
  • Immunity (production of immune cells, fight
    infection)
  • Growth (of muscle and soft tissue)
  • Deficiency Night Blindness
  • Toxicity symptoms IU 3000mcg/day, liver damage,
    joint pain, headaches
  • Food sources Liver, egg yolk, milk fat, butter
  • Stability cooking veggies can inactivate vit A
  • best absorption w/ fat

10
Vitamin D
  • Functions
  • Absorption of calcium and phosphorus
  • Bone mineralization
  • Requirements none if exposed to sun
  • Deficiency Rickets (malformation of long bones
    in kids) and osteoporosis
  • Deficiency rare milk is fortified w/ Vit. D
  • Toxicity unusual, kidney damage
  • Food sources Milk, margarine

11
Vitamin D
  • OTC vitamin D (ie Caltrate w/ D)
  • From a plant source
  • Humans lack enzyme needed to adequately absorb
    vit. D
  • We only absorb about 1
  • Rx vit. D much more effective Drisdol
  • given orally, weekly or monthly
  • recommended for US residents living north
    of
  • Virginia, less daily sunshine
  • Kidneys must activate Vit. D
    first

12
Child with Rickets
13
Vitamin E
  • Functions
  • Antioxidant (prevents oxidation of molecules
    prevents free radicals from changing healthy
    cells, accepts oxygen)
  • Deficiency Hemolytic anemia (breakdown of RBC),
    premature infants
  • Toxicity none
  • Food sources vegetable oils, nuts, avocado,
    fortified cereals

14
Vitamin K
  • Functions
  • Blood clotting
  • Bone development
  • Requirements intestinal bacteria produces vit. K
  • Deficiency Uncommon, newborns, long term
    antibiotic use
  • Toxicity none
  • Food sources green, leafy vegetables
  • Spinach, broccoli, turnip greens)

15
Water-Soluble Vitamins Vitamin C (Ascorbic
Acid)
  • Functions
  • Build connective tissue (collagen)
  • Antioxidant function (protect from free rad.)
  • Helps w/ absorption of iron
  • NOT truly proven to treat colds URIs
  • Requirements More w/ preg, lactation, smokers
  • Deficiency Scurvy
  • Toxicity tissue, gum bleeding, soft teeth, poor
  • wound healing
  • Food sources strawberries, melon, oranges,
  • tomato, broccoli, potato, peppers,
    cabbage

16
Thiamin (Vitamin B1)
  • Functions needed for utilization of energy,
    helps metabolize carbohydrates
  • GI system (normal appetite, digestion and
    elimination)
  • CNS (alertness, normal reflexes)
  • CV (normal function)
  • Requirements increased in pregnancy
  • Deficiency Alcoholism, Beriberi (CNS)
  • Food sources beef, pork, enriched grains,
    legumes

17
Riboflavin (Vitamin B2)
  • Functions
  • Energy production
  • Tissue building
  • Requirements increased w/ preg. lactation
  • Deficiency usually occurs with protein
    malnutrition
  • Toxicity none
  • Food sources Milk !

18
Niacin (Vitamin B3)
  • Functions
  • Energy production (extracts energy from CHO, fat,
    prot.)
  • Helps to improve lipid levels
  • Requirements higher w/ preg., lact.
  • Deficiency Pellagra (4 Ds)
  • Toxicity from supplements reddened skin w/
    itching and burning
  • Food sources meat, poultry, fish, whole grains

19
Niacin Defeciency
  • 4 Ds
  • Pellegra
  • Dermatitis
  • Diarrhea
  • Dementia
  • Death

20
Folate
  • Functions
  • Regulation of blood homocysteine levels high
    levels can cause CV disease !
  • Reduces likelihood of neural tube defects in
    unborn
  • Requirements 400 mcg/day. Pregnant women, women
    of child bearing age should take in dietary form
    supplements 600mcg/day
  • Deficiency diseases Neural tube defects (spina
    bifida, anencephaly)
  • Toxicity minimal, some nerve damage
  • Food sourcesgreen leafy veg, beans, OJ

21
Vitamin B12 (Cobalamin)
  • Functions
  • Regulation of blood homocysteine levels
  • Hemoglobin production
  • Nervous system functioning
  • Requirements higher w/ preg, lact.
  • Deficiency Pernicious anemia (irreversible nerve
    damage)
  • Toxicity none
  • Food sources lean meats, clams, oysters, crab

22
Vitamin Supplementation
  • Ongoing debateyes or no ??
  • Biochemical individuality the bodys chemical
    composition varies for each person, this also
    changes based upon
  • Life cycle needs
  • Pregnancy and lactation (folic acid )
  • Infancy (vit K at birth)
  • Children and adolescents (rapid growth)
  • Aging (decreased food intake)

23
Vitamin Supplementation, contd
  • Lifestyle
  • Oral contraceptive use (may lack B C)
  • Restricted diets (vegetarians may lack B12)
  • Exercise programs (may need more riboflavin)
  • Smoking (need more vit. C)
  • Alcohol (thiamin, folate)
  • Caffeine (4-6 c/day coffee diuretic effect
    may lack Bs)
  • Disease (increased nutrient needs)

24
Vitamin Supplementation, contd
  • Megadoses
  • Toxicity megadose of fat soluble vitamins (vit.
    A) - liver/brain damage fat sol. stored
    in body
  • Vit. B6 - folate (over 5 gm/day) - severe nerve
    damage
  • Vit. C (ascorbic acid) (over 2 gm/day) -kidney
    stones
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