Unit XI: Fat Soluble Vitamins

1

Chapter 11 Fat Soluble Vitamins ADEK
2
Chapter 11 - FSV

• Characteristics of fat-soluble vitamins
• Do not dissolve in water, but dissolve in fat or
  organic solvents.
• Dietary fat soluble vitamins need bile for
  absorption.
• The fat-soluble vitamins include vitamins A, D,E
  and K
• Found in the fats and oils of foods.
• Stored in the liver and fat tissue until needed
• not readily excreted from the body.
• Risk of toxicity.

3
Storage of vitamins in the body

• Vitamins A, D and E
• These three fat-soluble vitamins can accumulate
  in the liver and fat tissue of the body and are
  not readily excreted. Long-term intakes more
  than the RDA can be toxic, particularly vitamins
  A and D.
• Vitamin K
• The other fat-soluble vitamin, vitamin K, is
  readily excreted from the body.

4
Absorption transport

• The fat-soluble vitamins, like lipids are
  absorbed with dietary fat.
• Bile aids in the absorption of fat-soluble
  vitamins.
• The GI must function adequately for efficient
  uptake of fat-soluble vitamins.
• Under normal conditions, healthy individuals will
  absorb 40-90 of fat-soluble vitamins.

5
Absorption Transport

• Fat malabsorption interfere with the absorption
  of FSV.
• Unabsorbed fat is excreted as feces.
• The following conditions adversely affect the
  uptake of fat-soluble vitamins
• Cystic fibrosis
• Crohns disease
• Celiac disease
• Certain medications

6

Vitamin A

• Family of compounds called Retinoids
• Retinol supports reproductive functions
• Found in animal foods and nutrient supplements.
• Can converted to retinoic acid and retinal in the
  body.
• Retinal Aid in vision
• Retinoic acid regulates growth
• 90 of retinoids are absorbed
• These are preformed Vitamin A form that the
  body readily uses. Found only in animal sources

7
Provitamin A carotenoids

• Found in plant sources
• Not biologically available until they are changed
  into one of the retinoids in the body
• There are over 600 different carotenoids only 3
  can be converted to vitamin A
• Beta carotene (most common form)
• Alpha carotene
• Beta- cryptoxanthin
• Accounts for 25 35 percent of dietary vitamin A
  consumed in the US

8
Functions of Vit A

• Essential for healthy eyes
• Promotes cell differentiation
• Determines what cell becomes in your body
• Supports reproductive system, development of
  limbs, heart eyes and ears
• Promotes bone and teeth growth
• Play a role in immunity and preventing infections
  by creating white blood cells
• Carotenoids, which act as antioxidants, decrease
  the damaging effects of free radicals.

9
Sources of Vitamin A

• Sources
• Preformed Vit A
• Organ meats (liver), milk, cereals, cheese and
  eggs are the most popular sources of
• Provitamin A (carotenoids)
• Fruits peaches, apricots, cantaloupes, mangoes,
  papaya
• Vegetables tomatoes, carrots, winter squash,
  sweet potatoes, broccoli, romaine lettuce,
  collard greens and spinach.
• Adding as little as 1 tablespoon of vegetable oil
  to your diet can increase absorption of
  carotenoids by as much as 25

10
Vitamin A

• RDA can be measured in micrograms of retinoic
  activity equivalents (RAE) or in international
  units (IU). 1 RAE 3.3 IU
• 900 microgram for men
• 700 microgram for women
• Upper limit 3,000 microgram/day
• Deficiency
• Night blindness difficulty seeing at dusk,
  cant adjust from day light to dark
• Vitamin A deficiency is the main cause of
  non-accidental blindness (Xerophthalmia)
• Many die after blindness as a result of
  infection.
• The eye becomes prone to infections when the
  conjunctiva is damaged.
• Infections can spread systemically throughout the
  body.

11

12
Toxicity

• Hypervitaminosis A - is a condition that results
  from excessive intake of vitamin A from
  supplements
• Cause defective physical development during early
  development of the fetus resulting in birth
  defects
• Even 3X RDA vitamin A is considered risky during
  pregnancy.
• Accutane is associated with congenital
  malformations result involving the head and
  brain.
• FDA has recommended that women of childbearing
  years limit their vitamin A intake to 100 RDA

13
Toxicity

• High consumption of vitamin A has been linked to
  osteoporosis and increased risk of fractures
• Provitamin A carotenoids in foods are not toxic
• Extra carotenoids are stored in the liver and in
  the fat under the skin, causing carotenodermia

14

Fig. 11-7, p. 375
15
Vitamin D/calceferol

• Also called the sunshine vitamin because it is
  made with the help of ultraviolet (UV) rays from
  sunlight
• Vitamin D enters your body in an inactive form
• The kidneys convert dietary vitamin D into the
  active form
• Precursor bodys cholesterol

16
Vitamin D/ calceferol

• Functions of Vit D
• Helps bone health by regulating calcium and
  phosphorus concentration in the blood
• When blood concentration of calcium is low,
  vitamin D and parathyroid hormone signals the
  kidney to decrease excretion of calcium and
  phosphorous
• Sources of vit D
• Fortified milk, cereals, yogurt, fatty fish

17
Vitamin D

• Adequate Intake
• 5 micrograms/day for 19-50 yr
• 10 micrograms/day for 51-70 yr
• 15 micrograms/day for gt70 yr
• Upper level 50 micrograms/day

18
Vitamin D

• Deficiency
• Rickets in children (soft bones)
• poor bone mineralization
• Bowed legs
• Unable to hold up their own weight when standing
  up
• Recently researchers have found a rise in rickets
  among children,
• linked to increase consumption of soft drinks
• Limited outdoor activities
• Fear of skin cancer
• Air pollution reduces ultraviolet rays of the sun
  by as much as 60

19
(No Transcript)
20
Vitamin D

• Osteomalacia - adult form of rickets
• Occurs in women with decreased calcium and
  phosphorus intake
• Causes bone weakness and pain
• Can lead to osteoporosis

21
Vitamin D Toxicity

• Hypervitaminosis D associated with
  over-consumption of supplements
• Increased calcium withdrawal in bones and
  intestines
• Increased calcium and phosphorous
• concentrations in the blood (hypercalcemia)
• Increase calcium deposits in kidneys, lungs,
  blood vessels and heart

22
Vitamin E

• Vitamin E is an effective antioxidant
• Prevent oxidation of lipids, vit A and LDL to
  prevent build-up in the arteries
• Neutralize free radicals before they damage cell
  membranes
• Prevents blood clotting in the blood by acting as
  anticoagulant
• There are 8 different forms, only one is active
  in the body (alpha- tocopherol)
• The synthetic is only half as active as the
  natural

23
Vitamin E

• Sources
• Polyunsaturated plant oils (vegetable oils)
• Nuts and seeds
• Leafy green vegetables
• Fortified cereals
• RDA
• Adults need 15 milligrams/day
• Upper limit is 1,000 milligrams

24
Vitamin E

• Deficiency
• Erythrocyte hemolysis in premature infants (red
  blood cell destruction causing anemia)
• Toxicity from synthetic form or fortified foods
• increase risk of hemorrhage
• A deficiency of vitamin K can increase the
  anticoagulant effect

25
Vitamin K

• There are two forms of vitamin K
• Menaquinone synthesized by the intestinal tract
• Phylloquinone found in green plants
• Functions
• Essential for blood clotting
• Vitamin K plays a role synthesizing clotting
  factors
• Without vit k a simple cut on the finger would
  cause uncontrollable bleeding
• Synthesis of bone protein (osteocalcin) that
  regulates blood calcium.

26
Vitamin K

• Inadequate amount of vitamin K may contribute to
  osteoporosis, associated with increased risk of
  hip fractures
• Sources
• Intestinal bacteria can make vitamin K but not
  enough to meet all of the bodys needs
• Leafy green vegetables
• Cabbage family vegetables
• Vegetable oils and margarine

27
Vitamin K

• Deficiency
• Newborn infants receive a single dose of vitamin
  K at birth because of a sterile intestinal tract
  to prevent hemorrhagic disease
• Rare in healthy individuals
• Toxicity
• No known adverse effect from consuming too much
  vitamin K from food or supplement
• Interferes with anticlotting medication (coumadin)

28
Recommendation for Vitamin K

• Adequate Intake (based on amount that is consumed
  on average)
• Infants 2 2.5 microgram
• Children 30 55 microgram
• Men 60 120 microgram
• Women 60 90 microgram

29
Homework/extra credit

• 5 points
• Complete the vitamin/mineral evaluation form
  posted on the course website