This lecture talks about fat soluble vitamins in regards of their structure, functions and abnormalities.

1. Fat –soluble vitamins
Peaks Medical Academy

2. Objectives…
Discuss the important fat soluble vitamins in
terms of:
a) Functions
b) Sources
c) Abnormalities

3. fat-soluble vitamins
 They help our bodies function & stay
healthy.
 The fat-soluble vitamins, A, D, E,
and K, are stored in the body for
long periods of time and generally
pose a greater risk for toxicity than
water-soluble vitamins (B1, B2, B6,
B12, niacin, biotin, folic acid and
ascorbic acid (vitamin C).
 when consumed in excess, well-
balanced diet will not lead to toxicity.

4. Vitamin A

5. functions
1-Helps with
vision and eye
health.
2- Promotes
healthy skin.
3- Supports
bone and tooth
growth.
4- Maintains
healthy immune
system.

6. sources of vitamin A
 The recommendation for vitamin A
intake is expressed as micrograms
(mcg).
 Foods from animal source provide
various retinoid.
 Amounts exceeding 7.5 mg/day of
retinol should be avoided.
 Excessive intake of vitamin A
produces a toxic syndrome called
hyper vitaminosis A.
 Milk, Egg, Spinach, Broccoli, Carrot,
Meat, Papaya, liver.

7. Beta-Carotene
 In addition to its antioxidant
property, Beta- Carotene also
has been shown to have
anticancer action.
 It increases the number of
receptors on WBC for a
molecule known as "major
histocompatibility complex I".

8. Hydrolysis of beta carotene

9. This figure represents
a schematic
presentation for the
activation process of
B-carotene to retinol
in the small intestine

10. FORMS OF VITAMIN A
 Vit A occur in 3 different forms:-
•R = CH2OH
Retinol an
alcohol
•R = CHO
Retinal an
aldehyde
•R = COOH
Retinoic acid an
acid and most
oxidized form

11. Vitamin A - deficiency
 prolonged deficiency →
impairment to adapt to dim light
 more prolonged deficiency
leads to night blindness.
 Conversion of the urinary tract
epithelium to higher frequency
of urinary stone formation.
 Extremely dry skin, hair or nails.

12. Vitamin E

13. Vitamin E
 Vitamin E refers to a group of
eight fat-soluble compounds
that include both tocopherol
and tocotrienol.
 The vitamin is synthesized
by plants, and has eight
different isoforms (Vitamers)
divided into two classes of
four Vitamers each.

14. Tocopherols are saturated
(Single bonds)
Tocotrienols are unsaturated
(Have double bonds)

15. Mechanism of action of antioxidants, vitamin E
 Free radicals, such as superoxide,
hydroxyl ions and nitric oxide all
contain an unpaired electron.
 These radicals can have a negative
effect on cells causing cell damage
that leads to cell death.
 Antioxidants, such as vitamin E due
to its lipid solubility is particularly
important in protecting cell
membranes.
 The resulting the free radical is then
reduced by glutathione, vitamin C or
other molecules. Thus the free
hydroxyl group on the aromatic ring
is responsible for the antioxidant
properties.

16. Uses of Vitamin E as prophylaxis and Therapy
1. Cardiovascular disease(e.g. angina
pectoris and venous thrombosis):
It reduces oxidation of cholesterol in LDL
and VLDL particles which reduces risk of
coronary heart disease.
2. Anemia:
It functions as an antioxidant, enhancing
function and durability of RBCs and stabilizes
their membranes decreases syndromes of
hemolytic and sickle-cell anemia.
3. Immunity:
It increases resistance to viral and
bacterial infections and increases
antibody production by WBCs and
increases phagocytosis.

17. Uses of Vitamin E as prophylaxis and Therapy
4. Alzheimer's disease (AD) and
memory loss:
It can slow progression of AD and help
maintain memory function through
decreasing oxidative damage to neurons.
5. Eye Diseases:
It reduces oxidative damage to the lens,
decreases developing of cataract and
also decreases incidence of macular
degeneration.

18. Distribution and requirement of vitamin E
 The natural form of
the vitamin is
synthesized only by
plants and is found
predominantly in
plant oils.

19. Comparison of Tocotrienol and Tocopherol
Tocotrienol are forms of
natural vitamin E that can
protect against brain cell
damage, prevent cancer
and reduce cholesterol
The unsaturated side-
chain in tocotrienol causes
them to penetrate tissues
with saturated fatty layers
more efficiently making
them ideal for anti-aging.
Tocotrienol are better able
than tocopherol at
combating oxidative stress
of skin that had been
exposed to UV rays of the
sunlight.

20. Vitamin K

21. Vitamin K
 The principal role of Vitamin K is in the post-translational
modification of various blood clotting factors.
 Vitamin K serves as a coenzyme in the carboxylation of certain
glutamic acid residues present in these proteins.
 Vitamin K exists in several forms, for example:
A. phylloquinone (or vitamin K1 ) in plants
B. menaquinone (or vitamin K2 ) in intestinal bacterial flora
C. menadione ( a synthetic derivative of vitamin K ) used in therapy
 Vitamin K is found in cabbage, cauliflower, spinach.

22. Structure of vitamin K
Vit. K1 (Phylloquinone)
Vit. K2 (Menaquinone)
Vit. K3 (Menadione)

23. Functions
1)Plays key role in
blood clotting.
2)Prevents excessive
bleeding.

24. Drugs Interaction with Vitamin K
 Some interactions may increase the need for vitamin K:
Antibiotics
•Prevent absorption and
kill normal bacterial flora.
Anticonvulsants
•e.g. Phenytoin : Affect
Vit K metabolism.

25. Vitamin D

26. Vitamin D
 They are sources of preformed vitamin D
activity and they differ chemically only in
the presence of an additional double
bond and methyl group in the plant sterol
(plant sterol = Ergocalciferol).
 Ergocalciferol (Vit.D2) found in
plants.
 Cholecalciferol (Vit.D3) found in
sun and animal tissue.

28. Function of vit D
1- Increasing the uptake
of Ca++ by the intestine.
2- Minimizing loss of
Ca++ by Kidney.
3- Stimulating
resorption of bone
when necessary.
4- SUPPORTS BONE
HEALTH
5-
REDUCES/CONTROLS-
INFLAMMATION
6- SUPPORTS IMMUNE
SYSTEM
7- HELPS WITH
MUSCLE FUNCTION
8- SUPPORTS BRAIN
CELL ACTIVITY