4. 4
Classification of vitamins
There are about 15 vitamins, essential for humans.
They are classified as
● Fat soluble (A, D, E and K) and
● Water soluble (C and B-group) vitamins.
The B-complex vitamins may be sub-divided into
energy-releasing (B1, B2, B3, B6, biotin etc.) and
hematopoietic (folic acid and B12).
5. Water Soluble Vitamins
Thiamin (B-1)
Riboflavin (B-2)
Niacin (B-3) Vitamin C
Pyridoxine (B-6)
Folic acid(B-9)
Cyanocobalamine(B-12)
Biotin(B-7)
Pantothenic Acid(B-5)
9. The Retinoids
• 3 forms of vitamin A
important for health
– Retinal
– Retinoic acid
– Retinol (key player; can be
converted to other forms)
• β-carotene (a carotenoid
or pigment) in
yellow/orange foods is a
potent provitamin A
10. Carotenoids
Additional physiologic effects
beyond vitamin A
Serving as an “antioxidant”
Remove excess “electrons”
from cell system
Electrons (free radicals)
damage cells and DNA
Can cause mutations
Protecting from cancer (related
to antioxidant function?)
Protecting from heart disease?
Supports immune system
function
11. Vitamin A Roles in the Body
• Promote vision (retinal)
– Maintenance of the cornea
– Converting light energy into nerve impulses
• Participate in protein synthesis and cell differentiation
– Differentiation of epithelial and goblet cells (retinoic acid)
• Support reproduction and growth
• Support immunity (retinoic acid and carotenoids)
• Involved in bone growth and remodeling
• Synthesis of glycoproteins
• Antioxidant activity (β-carotene)
12. Vitamin A - Deficiency
• More obvious deficiency symptoms than other
vitamins
– Night blindness
– Cell keratinization
• Dry skin
• Xerophthalmia (dryness of cornea & conjunctiva)
– Reproductive failure
– Abnormal skeletal development/maintenance
– Immune dysfunction
16. Vitamin A Deficiency - Reproduction
In females:
Increased abortions
Neonates born dead/weak
Deformed young: no eyeballs;
hydrocephalus
In males:
Keratinization of testicular
epithelium
18. Vitamin D - Sources
Not found naturally in many
foods
Synthesized in body
Plants (ergosterol)
Sun-cured forages
Fluid milk products are fortified
with vitamin D
Oily fish
Egg yolk
Butter
Liver
Difficult for vegetarians
19. Vitamin D: The Sunshine Vitamin
• Not always essential
– Body can make it if
exposed to enough
sunlight
– Made from
cholesterol in the
skin
20.
21. Vitamin D
• Vitamin D = calciferol
• Vitamin D2 = ergocalciferol
– Completely synthetic form produced by the
irradiation of the plant steroid ergosterol
– Plant source – cannot be used by birds
• Vitamin D3 = cholecalciferol
– Produced photochemically by the action of
sunlight or ultraviolet light from the precurs or
sterol 7-dehydrocholesterol
22. Formation of Vitamin D
• Skin (UV light)
– 7-dehydro cholesterol vitamin D3
– Ergosterol vitamin D2
• Liver
– OH-group added
• 25-hydroxy vitamin D3
• Storage form of vitamin (~3 months storage in liver)
• Kidney
– OH-group added by 1-hydroxylase
• 1,25-dihydroxy vitamin D3
• Active form of vitamin D, a “steroid hormone”
– OH-group added by 24-hydroxylase
• 24,25-dihydroxy vitamin D3
• Inactive form of vitamin D, ready for excretion
23. Vitamin D - Functions
• Functions
– Bone development
• Calcium absorption (small intestine)
• Calcium resorption (bone and kidney)
• Maintain blood calcium levels
• Phosphorus absorption (small intestine)
– Hormone
• Regulation of gene expression
• Cell growth
24. Vitamin D - Deficiency
Young animals
Rickets
Failure of bones to grow properly
Results in “bowed” legs or knock-knees, outward bowed chest and
knobs on ribs
Older animals
Osteomalacia: Adult form of rickets
Softening of bones, bending of spine, and bowing of legs
Osteoporosis (porous bones):
Vitamin D plays a major role along with calcium
Loss of vitamin D activity with advancing age
Associated with fractures.
Poultry
Decreased egg production & hatchability
Thin-shelled eggs
34. Vitamin E - Deficiency
• Rare – typically associated with fat malabsorption or
excessive intake of polyunsaturated fatty acids
(PUFAs)
– Erythrocyte hemolysis and hemolytic anemia
• Red blood cell breaks open and spill the contents, perhaps due to
PUFA oxidation
• Observed among newborns of several species
• Vitamin E treatment resolves hemolytic anemia
– Prolonged deficiency causes neuromuscular
dysfunction; affects the spinal cord and the retina
• Degeneration of nerve cells (poultry)
35. Vitamin K - Sources
Bacteria in the large intestine (10-
15%) or rumen
Plant sources
Green leafy vegetables
Animal sources
Liver
Milk
36. Forms of Vitamin K
• K1, phylloquinone
– Chloroplasts in plants
• K2, menaquinone
– Bacterial synthesis
• K3, menadione
– Synthetic, water soluble
form
– Complexed to improve
stability
37. Functions of Vitamin K
• Clotting factors are synthesized
in the liver as inactive
precursors - vitamin K converts
them to their active forms
– Conversion of prothrombin to
thrombin, an active enzyme
– Formation of fibrinogen to
fibrin, leading to clot formation
• Stimulates bone formation and
decreases bone resorption
38. Vitamin K - Deficiency
• Primary deficiency rare; secondary deficiency occurs
when fat absorption is impaired (e.g., cystic fibrosis,
Crohn’s disease) or following long-term or high-dose
administration of antibiotics (they kill the bacteria in
large intestine)
– Newborn babies with sterile GI tract; single
vitamin K dose given to prevent hemorrhage
• Prolonged clotting time
– Generalized hemorrhages
39. Vitamin K Deficiency in Human
Hemorrhagic disease in first few days of life;
death caused by subdural hemorrhage
40. 40
Vitamin Other Names Active Form
Vitamin-A Retinol
Retinal
Retinoic acid
-Carotene
Retinol
Retinal
Retinoic acid
Vitamin-D Cholecalciferol(Vit-D3)
Ergocalciferol(Vit-D2)
1,25-Dihydroxy-
cholecalciferol
(Calcitriol)
Vitamin-E -Tocopherol Any of several
tocopherol
derivatives
Vitamin-K Phylloquinone(Vit-K1)
Menaquinone(Vit-K2)
Menadione(Vit-K3)
Phylloquinone
Menaquinone
Menadione
41. 41
Vitamin Function
Vitamin-A Vision, Maintenance of reproduction, growth and differentiation,
maintenance of epithelium and skin.Glycoprotein synthesis, and
-carotene as an antioxidant and anticancer.
Vitamin-D Promotes Ca & P absorption from the intestine.Coordinates the
remodeling action of osteoclasts and osteoblasts. Increases
reabsorption of Ca & P by the renal tubules and also minimizes
excretion of Ca & P.
Vitamin-E Most powerful natural antioxidant, breaking free radical chain
reaction.First line of defense against peroxidation of PUFA,
maintain structural and function integrity of cells, protects RBC
from hemolysis, prevent sterility.
Vitamin-K Post – translational modification of factor II, VII, IX & X
(-carboxylation of glutamate residue).
42. 42
Vitamin Deficiency manifestations
Vitamin-A Nyctolopia, xerophthalmia, bitot’s spots
keratomalacia , Growth retardation,
decreased protein synthesis, lowered
glycoprotein content in the cell & reduced
immunity against infections.
Vitamin-D Rickets in children
osteomalacia in adults
Vitamin-E Rare
In human volunteers, induced deficiency
causes increased fragility of RBC, muscular
weakness, and neurological symptoms.
Sterility in rats.
Vitamin-K Rare in adults,
Hemorrhagic Disease in newborns
43. 43
Vitamin Dietary Sources RDA
Vitamin-A Fish liver oil, liver, kidney,
egg yolk and dairy
products. Carrot,
papaya, mango & green
leafy vegetables.
5000 IU
(1000 µg)
1IU=0.3µg
Vitamin-D Fish liver oil, Egg yolk, etc., 200 IU =10µg
Vitamin-E Vegetable oils 10 mg
Vitamin-K Alfaalfa, cabbage,
cauliflower and other green
vegetables.
Egg yolk, meat, liver,etc.,
Not of much
importance
but about 70-
140mg
