Vitamins nagamani

VITAMINS
Mrs.Nagamani.T, MSc Nursing
Quality Health Care College of Nursing

Introduction: Vitamins
• Vitamins are organic compounds that people need in
small quantities.
• Vitamins are found in almost everything we eat
• Most of the vitamins are not synthesized in the body and
hence they must be supplied in the diet.
• Few vitamins are synthesized in the body. Most of them
are present in diet as precursors.
• The precursor forms of vitamins are called as
provitamins. In the body these provitamins are converted
to vitamins.

Definition
• A vitamin is an organic molecule (or a set of molecules
closely related chemically, i.e. vitamers) that is
an essential micronutrient which an organism needs in
small quantities for the proper functioning of
its metabolism

Classification of Vitamins
• Vitamins are divided into two groups.
1. fat soluble vitamins
2. water soluble vitamins.
Fat Soluble Vitamins
• They are vitamins A, D, E and K. They have some common
properties.
They are:
1. Fat soluble.
2. Require bile salts for absorption.
3. Stored in liver.
4. Stable to normal cooking conditions.
5. Excreted in feces.

IMPORTANCE OF VITAMINS
1. Vitamins are essential for
reproduction. However, they
production.
growth, maintenance and
are not used for energy
2. Fat soluble vitamins are required for normal colour vision,
blood clotting, bone formation and maintenance of membrane
structure.
3. Most of the water soluble vitamins function as coenzymes or
prosthetic groups of several enzymes involved in
carbohydrate, lipid and amino acid metabolism etc.
4. Vitamins A and D act as steroid hormones.
5. Deficiency of fat soluble vitamins produce night blindness,
skeletal deformation, haemorrhages and hemolysis.

IMPORTANCE (Cont..)
6. Deficiency of water soluble vitamins produce beriberi,
glossitis, pellagra, microcytic anaemia, megaloblastic
anaemia and scurvy.
7. Some vitamin analogs are used as drugs. For example folic
acid analogs are used as anticancer agents and antibiotics.
8. Moderate consumption of some vitamins is found to decrease
occurrence or severity of some diseases.
For example carotenes, Vitamin E and Vitamin D
consumption at moderate evel reduces incidence of cancer
and cardiovascular diseases.

IMPORTANCE (Cont..)
9. Consumption of vitamin C in significant amounts reduces
severity of cold. They slow down ageing process also.
However, excessive consumption of fat soluble vitamins leads
to toxicity.
10.Vit B12, Folic acid and Vit B6are beneficial to coronary artery
disease patients. They lower plasma homocysteine levels.

WATER SOLUBLE VITAMINS
• VITAMIN B COMPLEX GROUP

Water Soluble Vitamins
• They are the members of vitamin B complex and
Vitamin C.
Their common properties are
 Water solubility.
 Except Vitamin B12others are not stored.
 Unstable to normal cooking conditions.
 Excreted in urine.

WATER SOLUBLE VITAMINS
VITAMIN B COMPLEX
Members of vitamin B complex are
(1) Thiamin (Vitamin B1)
(2) Riboflavin (Vitamin B2)
(3) Niacin
(4) Pyridoxine (Vitamin B6)
(5) Biotin
(6) Folic acid
(7) Cyanocobalamin (Vitamin B12)
(8) Pantothenic acid.

THIAMIN OR VITAMIN B 1
• Very important vitamin to prevent Beriberi that was
discovered in the West Indies
• A Japanese surgeon in the navy found that beriberi on ships
could be avoided by adding meat and whole grains to the diet
Chemistry
• It is a heat labile sulfur containing vitamin. It contains
pyrimidine ring and thiazole ring which are joined
by methylene bridge.
• It is highly alkaline sensitive.
Absorption and Transport
• It is absorbed in small intestine by active transport mechanism
and simple diffusion. Then it reaches liver through circulation.

THIAMIN
Function
• Thiamin pyrophosphate (TPP) is the active form of
thiamin.
• It is formed from thiamin in presence of ATP in a reaction
catalyzed by thiamin kinase present in liver.
• TPP is the prosthetic group of enzymes like pyruvate
dehydrogenase, α
- keto glutarate dehydrogenase etc.

THIAMIN
Sources
•
•
• Rich Sources. Outer coatings of food grains like rice,
wheat and yeast.
Good sources. Whole cereals, pulses, oilseeds and
nuts.
Fair sources. Meat, liver and egg and fish.
Thiamine Deficiency
1. Adult beriberi. Early signs of beri beri are insomnia,
headache, dizziness, loss of appetite, muscle weakness,
numbness and pricking sensation in lower limbs and
fatigue.

Thiamine Deficiency
If not treated it leads to
(a)Wet beri beri. In which cardiovascular system is affected and
it is characterized by edema.
Edema appears in lower limbs, trunk, face and serous
cavities. Blood pressure becomes abnormal. Heart becomes
weak and death occurs due to heart failure.
(b)Dry beri beri. In which central nervous system is affected. In
addition to early signs severe muscle wasting occurs. As a
result individual is unable to walk and becomes bed ridden.
Death may occur if not treated.
2. Infantile beri beri. In infants thiamine deficiency causes
infantile beri beri. It occurs in infants between 2-10 months of
age.

RIBOFLAVIN OR VITAMIN B 2
Chemistry
• It contains heterocyclic isoalloxazine ring and ribitol a sugar
alcohol. It is sensitive to light and alkali but stable to heat and
acidic medium.

• Absorbed in small intestine and distributed to all tissues by
circulation.
Functions
• Active forms of riboflavin are FMN and FAD. They act as
prosthetic groups of several enzymes. FMN is flavin
mononucleotide and FAD is flavin adenine dinucleotide.They
act as carriers of hydrogen atoms in redox reactions.
Sources
• Whole grains, legumes, pulses, green leafy vegetables, yeast,
eggs, milk and meat are good sources.
• Root vegetables and fruits are fair sources.
Riboflavin (Vitamin B2)

RDA for Riboflavin
• The recommended dietary intake for
riboflavin is 1.3 mg / day .

Riboflavin (Vitamin B2)
Riboflavin Deficiency
• In humans riboflavin deficiency causes oral, facial, occular
lesions.
(a)Angular Stomatitis. Lesions of mouth particularly at corners of
mouth.
(b) Cheliosis. Red swollen and cracked lips.
(c) Swollen and dark tongue
(d)Vascularization of cornea and conjuctiva and blood shot
eyes.
(e) Glossitis. Inflammated magenta coloured tongue.
(f) Anaemia

NIACIN OR VITAMIN B 3
• Niacin is the compound that prevents development of
Pellagra.
• It was isolated from nicotine acid
Chemistry
• The word niacin refers to two pyridine derivatives. They are
nicotinic acid and nicotinamide.
• Both are highly stable to heat and stable to alkali and acid.
Absorption and transport
• Nicotinic acid and nicotinamide are absorbed in small
intestine and reach various tissues through circulation where
they are converted to NAD and NADP.

Niacin
Functions
• Nicotinamide is component of two coenzymes NAD and
NADP. NAD is nicotinamide adenine dinucleotide and NADP
is nicotinamide adenine dinucleotide phosphate.
Sources
• Whole grains, peanuts, legumes, yeast, liver, fish and meat
are good sources.
• Milk and egg are poor source of niacin but rich source of
tryptophan. Vegetables and fruits are poor source of niacin.
Niacin Deficiency
• Niacin deficiency causes pellagra in which skin,
gastrointestinal tract and nervous system are affected.
• Dermatitis, Diarrhoea and Dementia are characteristic
symptoms of pellagra.

DEFICIENCY OF NIACIN
• Pellagra: dermatitis
• Muscular weakness
• Anorexia
• Indigestion
• Skin eruptions
• Diarrhea

Vitamin B 6 or Pyridoxine
• Very important vitamin since it plays a coenzyme role in more
than 100 enzymatic reactions.
Chemistry
• Three compounds derived from pyridineshow vitamin B6 activity. They
are pyridoxine, pyridoxal and pyridoxamine. Pyridoxine is stable to
heat and sensitive to light and alkali.
• Pyridoxine is easily absorbed and reaches various tissues through
circulation. In the tissues pyridoxine is converted to pyridoxal and
pyridoxamine.

PYRIDOXINE
Functions
• Pyridoxal phosphate is active form. It is formed from pyridoxal
by phosphorylation catalyzed by pyridoxal kinase.
• Pyridoxal phosphate act as prosthetic group or co enzyme of
enzymes which are involved in transamination,
decarboxylation, transsulfuration, desulfuration and non-
oxidative deamination reactions.
• Pyriodoxal phosphate is coenzyme for enzymes that are
involved in the synthesis of heme, serotonin, catecholamines
and coenzyme A synthesis.

PYRIDOXINE
Sources
• Whole grains, legumes, liver and yeast are good sources.
Leafy vegetables, milk, meat and eggs are fair sources.
Pyridoxine Deficiency
1. It is rare in human adults.
2. In children vitamin B6 deficiency causes epileptic form
convulsions (seizures) due to decreased formation of neuro
transmitters like GABA, serotonin and catecholamines.

SOURCES OF VITAMIN B 6
• Animal tissues
• Fish
• Poultry
• Whole grains
• Some fruits and vegetables mainly bananas ,
carrots, potatoes, garbanzo beans, avacado

DEFICIENCY OF VITAMIN B 6
• Weakness
• Sleeplessness
• Peripheral neuropathy
• Personality changes
• Dermatitis
• Glossitis

RECOMMENDATIONS FOR B 6
• RDA for vitamin B 6 is 1.3 – 2 mg / day

BIOTIN OR VITAMIN B 7
Biotin participate in reactions in which carbon dioxide is added to
a compound.
• Chemistry
• It is a sulfur containing vitamin. It consist of imidozole
ring fused to tetra hydro thiophene with valerie acid side
chain. It is stable to heat but alkaline sensitive.
• Absorption and transport
• It is absorbedin the small intestine and reaches liver
and other tissues through circulation

Function
• Biotin is prosthetic groups of several carboxylases like
pyruvate carboxylase, acetyl-CoA carboxylase, propionyl-CoA
carboxylase etc.
• Biotin is attached to e-aminogroups of Iysyl residue of
apoenzyme through, amide linkage. In carboxylation reaction
it acts as a carrier of CO2
Dietary sources
• Whole cereals, legumes, groundnuts, milk, meat and fish are
good sources. Vegetables and fruits are fair sources.
Biotin deficiency
• Biotin deficiency is rare in humans because it is present in
most of the common foods.

SOURCES OF BIOTIN
• Whole grains
• Eggs
• Nuts
• legumes

DEFICIENCY OF BIOTIN
• Skin rash
• Neurological disorders
• Impaired growth

RDA FOR BIOTIN
• RDA for Biotin is 30 μg /day for adults

FOLIC ACID
Chemistry
• Folic acid consist of pteridine nucleus, p-aminobenzoic acid
and glutamate. It is sensitive to light and acid but stable to
heat and alkali.
• Folic acid present in natural foods is called as folyl
polyglutamate. In the intestinal mucosal cells hydrolase form
folic acid which is reduced to N5- methyl tetrahydrofolate.
• Methyl tetrahydrofolate is the major circulating form probably
bound to protein.

Function
• Tetrahydrofolate or FH4 which is reduced form of folic acid is
carrier of one carbon units.
• Folic acid is required for the synthesis of DNA in rapidly
dividing cells like bone marrow or erythropoietic cells or
intestinal cells.
• Folic acid prevents neural tube defects (NTD) that occur
during fetal development.
Sources
• Green leafy vegetables like spinach, cabbage, ladyfinger,
curry and mint leaves, pulses like black gram, green gram,
eggs and liver are good sources. Coconuts, whole cereals
and milk are fair sources.

RDA FOR FOLATE
• RDA for adults is 400 μg / day

Deficiency of Folate
• Megaloblastic anaemia is the main symptom of folic acid
deficiency.
• It is most common in pregnant women and in unweaned
children.
• Reduced ability to synthetize DNA

CYANOCOBALAMIN (VITAMIN B12)
• Cyanocobalamin or vitamin B 12 is very imporatnt
vitamin
• It plays an important role in many Coenzymes
Chemistry
• It has complex chemical structure. It is made up of
Tetrapyrrole ring system called as corrin ring with a
central cobalt (Co) atom with molecular formula (C63 H88
N14O14PCO)

• The absorption of vitamin B12 takes place in ileum.
Transcobalamin II delivers vitamin B12to tissues.
Storage
• Unlike other water soluble vitamins vitamin B12is stored in the
liver and other tissues.
Functions
• Vitamin B12act as prosthetic group or coenzyme.
Vitamin B12Deficiency
• Vitamin B12 deficiency affects bone marrow, intestinal tract
and neurological system. In vitamin B12 deficiency these
systems are affected because DNA synthesis, methionine
synthesis and fatty acid synthesis are altered.

RDA OF VITAMIN B 12
• RDA for adults is 2.4 μg /day
• Deficiency can cause anemia

PANTOTHENIC ACID VITAMIN B 5
• Part of Coenzyme A which plays an important role in energy
metabolism.
• Is essential for the formation of ATP from the breakdown of
carbohydrates, protein, fat and alcohol
Chemistry
• It is an amide of β-alanine and dihydroxy dimethyl butyric
acid (Pantoic acid)
• It is stable to heat but unstable to alkali or acid.
• Intestinal phosphatases release pantothenic acid from
dietary sources.
• Free pantothenate or its salts are freely absorbed
in the intestine and reach various tissues through
circulation.

SOURCES OF PANTOTHENIC
• Meat
• Milk
• Mushrooms
• Liver
• Peanuts
• Eggs
• yeast

Functions
• Pantothenic acid is a component of coenzyme A. Coenzyme
(CoA) participates in several enzymatic reactions of
carbohydrate, lipid and amino acid metabolism.
• It serves as carrier of
biosynthesis.
Pantothenic acid deficiency
acyl groups during fatty acid
• It cause burning feet, abdominal cramps, restlessness and
fatigue in humans.
Sources
• Organ meat, liver, milk, whole cereals, legumes and eggs are
good sources. Vegetables and fruits are poor sources.

DEFICIENCY OF B 5
• Headache
• Fatigue
• Impaired muscle coordination
• GI tract disorders

RDA FOR PANTOTHENIC ACID
• RDA for adults is 5 mg / day

VITAMIN C OR ASCORBIC ACID
• Is involved in many processes in human body
• The most important function for vitamin C is the synthesis of
collagen, the principal tissue protein found in tendon, arteries.
Chemistry
• It is a sugar acid known as hexuronic acid. Ascorbic acid
is easily oxidized by atomospheric O2 to dehydroascarobic
acid
• High temperature (cooking) accelerates oxidation.
• Light and alkali also promotes oxidation
• Vitamin C is readily absorbed in the intestine by sodium
dependent active transport mechanism and reaches various
body tissues through circulation. Ascorbic acid enters various
cells like erythrocytes, leucocytes etc. freely.

Functions
1. Ascorbic acid act as antioxidant. It is free radical scavenger.
Since it is a strong reducing agent it protects carotenes,
vitamin E and other B vitamins of dietary origin from oxidation.
2. It is required for the hydroxylation of proline and lysine
residues of collagen. Since collagen is component of ground
substance of capillaries, bone and teeth vitamin C is required
for proper bone and teeth formation also.
3.It participates in hydroxylation reactions of
biosynthesis.
4. It is required for catecholamine synthesis from tyrosine.
5. In the liver bile acid synthesis requires ascorbic acid.
steroid

6. It is required for the absorption of iron in the intestine. It
maintains iron in ferrous form.
7. Catabolism of tyrosine requires ascorbic acid.
8. Vitamin C is effective in controlling bacterial invasion by
inhibiting activity of bacterial hyaluronidase enzyme. It acts as
inhibitor of this enzyme due to structural similarity to
glucuronate of hyaluronin, the substrate of hyaluronidase.

Vitamin C deficiency
1. In adults deficiency of vitamin C causes scurvy. But it rarely
occurs in normal people.
The symptoms of scurvy are
(a)Haemorrhages in various tissues particularly in inside of
thigh, calf and forearm muscles. It may be due to capillary
fragility.
(b) General weakness and anaemia.
(c) Swollen joints, swollen gums and loose tooth.
(d) Susceptible for infections.
(e) Delayed wound healing.
(f) Bone fragility and osteoporosis.
2. Vitamin C deficiency in infants gives rise to infanitle scurvy. It
occurs in weaned infants who are fed on diets low in vitamin
C.

Sources
•
•
Guava, coriander and amarnath leaves, and cabbage are rich
sources. Fruits like lemon, orange, pineapple, papaya, mango
and tomato are good sources.
Apples, bananas and grapes are fair sources.
•

RDA FOR VITAMIN C
• RDA for vitamin c for adults is 60 mg / day

FAT-SOLUBLE VITAMINS
• VITAMIN A
• VITAMIN D
• VITAMIN E
• VITAMIN K

VITAMIN A
• Assists with formation of epithelium, skin and mucus membrane
• Maintains healthy eyes
• Assists with bone remodeling
• Chemistry
• They are retinol (Vitamin A alcohol), retinal (Vitamin A
aldehyde) and retinoic acid (Vitamin A acid).
• They are composed of β−ionine ring (methyl substituted cyclohexenyl
ring) and side chain containing two isoprene units with four
conjugated double bonds.
• Due to the presence of double bonds in isoprenoid side chain vitamin
A exhibits cis-trans (geometric) isomerism.
• Due to the presence of 4 double bonds vitamin A can be oxidized by
air or light slowly.

VITAMIN A
In nature vitamin A occurs in two forms
•
•
retinolesters -In the foods of animal origin.
carotenes - in plant foods as provitamin.
Absorption of Vitamin A
•
• In the intestine pancreatic esterase hydrolyzes retinolesters
present in the diet to retinol and free fatty acid in presence of
bile salts. Retinol is absorbed by mucosal cells.
Dietaryβ-carotene is cleaved into two molecules of retinal by a
dioxygenase present in the intestinal mucosal. It is
transported by lipoprotein.

Functions of vitamin A
The three major retinoids retinal, retinol and retinoic acid have
unique functions.
1. Retinal is required for normal and color vision.
2. Retinol is required for reproduction and growth.
3. Retinol is required for differentiation and function as steroid
hormone.
4. Retinoic acid is required for the synthesis of glycoproteins or
mucopolysaccharides.
5. Retinoic acid also act as steroid hormone. It also promote
growth and differentiation.
6. Retinol and retinoic acid are involved in regulation of gene
expression.

Retinal and colour vision
• Three light sensitive pigments present in cones are
responsible for colour vision. They are porphyropsin, iodopsin
and cyanopsin.
All three pigments contain 11-cis retinal and are sensitive to
red, green and blue colours respectively.
When the photon (light) strikes retina depending on the colour
of the light a particular pigment is bleached. This leads to
generation of nerve impulse and perception of colour by brain.
Defective apoprotein production due to faulty genes leads to
colour blindness.
•
•
•

Deficiency of Vitamin A
1. Night blindness
•
•
•
• In early stages, the affected individual is not able to see
clearly in dim light or night due to block in the resynthesis of
rhodopsin.
In the later stage of deficiency the affected individual cannot
see or read in dim light.
Thus loss of night vision (night blindness) is the major initial
symptom of Vitamin A deficiency.
Night blindness in adults or in preschool children is common
in countries where intake of vitamin A is low.
2. Growth of bone and formation of tooth are defective. Thick
and long bones are formed.
3. Nerve growth also affected. Degeneration of myelin sheath
occurs.

Deficiency of Vitamin A
4. Keratinisation of mucous secreting epithelial cells
(hyperkeratosis) lining respiratory tract and reproductive tract
occurs. Mucous secretion by salivary and lacrymal glands is
also affected.
5. Deposition of keratin in skin (xeroderma) gives rise to
characteristic toad skin appearance.
6. Reproductive disorders like testicular degeneration, resorption
of foetus or foetal malformation are observed.
7. Degenerative changes in kidneys.

Sources
(a) Animal sources.
• Marine fish oils like halibut liver oil, cod liver oil and shark liver
oils are excellent sources. Liver of sheep or goat is also
excellent source. Butter, egg, and milk are good sources.
Freshwater fish contain Vitamin A2 (dehydroretinol) which is
only 40% active.
(b) Plant sources. In plant foods vitamin A is present as
carotenes. Plant oil like red palm oil is excellent source.
• Leafy vegetables. coriander leaves, curry leaves, spinach and
cabbage are good sources.
• Yellow vegetables like carrot, pumpkin and sweet potato and
ripe tomatoes also contain appreciable amounts of vitamin A.
• Fruits. Yellow pigmented fruits papaya, mango, jackfruit,
banana and oranges also contain vitamin A in good amounts.

RDA of Vitamin A
• The Recommended Dietary Allowance (RDA) for men and
women is 900 and 700 μg retinol activity equivalents
(RAE)/day, respectively.
• The Tolerable Upper Intake Level (UL) for adults is set at
3,000 μg/day of preformed vitamin A.

VITAMIN D
• Considered as hormone that facilitates absorption of Ca
and P
• It assists with bone formation by aiding the absorption of
calcium
• It is also called sunshine vitamins.
• Its active forms are vitamin D2 (ergo calciferol) and vitamin D3
(cholecalciferol).
• Calcitriol is the most active form of vitamin D that acts as
steroid hormone.
• They are formed from provitamins which are sterols.

• Absorption, transport and storage
• Dietary vitamin D2 and vitamin D3 are absorbed in the small
intestine in presence of bile salts.
• Absorbed Vit D is incorporated into chylomicrons and
enters circulation via lymph.
• Vitamin D is stored in liver and adipose tissue.

Functions of calcitriol
1. Major action of calcitriol is to increase absorption of calcium
and phosphate in the intestine particularly in duodenum and
jejunum.
2. Calcitriol is required for bone formation and mineralisation of
bone. It increases synthesis of osteocalcin a calcium binding
protein of bone. Osteocalcin is involved in deposition of
calcium salts in bone.
3. Calcitriol affects calcium and phosphorus excretion by kidney.
It reduces the excretion of calcium and phosphorus.
4. Vitamin D is involved in maintenance of normal muscle tone.
5. Calcitriol is an immuno regulatory hormone. It stimulates cell
mediated immunity. It plays a vital role in
monocyte/macrophage activation.

Vit D deficiency symptoms
1. Rickets
• In children vitamin D deficiency causes rickets, results in soft
bones. This leads to deformities in skull, chest, spine, legs
and pelvis.
2. Osteomalacia
• Vitamin D deficiency causes osteomalacia in adults. It is seen
in pregnant women and women with inappropriate diet.
Skeletal pain is early sign. Deformities of ribs, spine, pelvis
and legs are seen.
3. Osteoporosis
• Vitamin D deficiency causes osteoporosis in old people.
Photolysis of provitamins dcreases with age. This and
together with decreased sex hormone production may lead to
deficiency.
• Symptoms are bone pain and porous bones. Bone fractures
are common.

Sources
•
•
Vitamin D is mostly present in foods of animal origin.
Marine fish liver oils like halibut liver oil, cod liver oil and shark
liver oil are good sources.
• Sardines, egg yolk and butter contains small amounts.
However, milk is a poor source of vitamin D, Mushrooms
contain small amounts of vitamin D.
Toxicity (Hyper vitaminosis)
•
• Ingestion of mega doses of vitamin D results in toxicity of Vit D.
Signs and symptoms of vitamin D toxicity are loss of appetite,
nausae, thirst, vomiting, polyuria and calcification of lungs,
renal tubules and arteries. Muscle wasting also occurs.
Demineralisation of bone similar to vitamin D deficiency is
seen.

Vitamin E
• Antioxident and promotes RBC formation
• Deficiency of vitamin E is heomlytic anemia
• RDA 15 mg / day
• Chemically they are tocopherol
• They are derivatives of tocol or 6-hydroxy chromane ring
with phytyl side chain.
• Tocopherols are alkaline sensitive and their vitamin
activity is destroyed by oxidation.
• Among all tocopherols α-tocopherol is most potent and
widely distributed in nature.
• Cooking and food processing may destroy vitamin E to
some extent.

Absorption, transport and storage
•
•
•
•
•
• Dietary tocopherols are absorbed in small intestine in the
presence of bile salts.
Absorbed tocopherols are incorporated into chylomicrons in
mucosal cells of intestine and enters circulation via lymph.
In plasma tocopherols are released from chylomicrons by
lipoprotein lipase.
Liver takes up half of tocopherol and it is stored.
Skeletal muscle and adipose tissue also stores vitamin E.
From the liver tocopherols are transported to other tissues in
β-lipoprotein.

Functions of Vitamin E
1. α-tocopherol in cell membrane and cytosol function as
antioxidant. It is present in high concentration in tissues which
are exposed to high O2 pressure like erythrocytes, lungs,
retina etc.
• It acts as chain breaking antioxidant.
2. Vitamin E is involved in maintenance of muscle tone
3. Vitamin E increases synthesis of hemeproteins
4. Vitamin E prevents dietary vitamin A and carotenes from
oxidative damage.
Sources
•
• Cereal germ oils like wheat germ oil, corn germ oil and
vegetable oils like coconut oil, sun flower oil, peanut oil,
ricebran oil, palm oil, mustard oil, cotton seed oil and
soyabean oil are rich sources of vitamin E.
Vegetables, fruits and meat are relatively poor sources of
vitamin E.

Vitamin K
• Assists in the synthesis of prothrombin required for
blood clotting
• Deficiency symptoms are prolonged bleeding and increased
clotting time.
• Chemically they are quinones
• Vitamin K1 also called as phylloquinone, is the major form of
vitamin found in plants particularly in green leafy
vegetables

• Vitamin K of dietary origin is absorbed in small intestine in
presence of bile salts.
• In mucosal cells of intestine absorbed vitamin K is
incorporated into chylomicrons.
•
•
•
It reaches liver after entering circulation through the lymph.
Liver distributes vitamin K to other tissues.
It rarely accumulates in liver and peripheral tissues.
Sources
Plant Sources
• Cauliflower, Cabbage, spinach, turnip greens, peas and
soybean are rich sources.
Animal sources
• Dairy products like cheese, butter and farm products like eggs
and liver are good sources.

Functions of Vitamin K
•
• Vitamin K is required for the synthesis of blood clotting factors
like prothrombin (factor II), cothromboplastin (factor VII),
(factor IX) and (factor X).
It is required for the carboxylation of the γ
-carbon atom of
glutamic residues of these factors. The γ-carboxylation
generates calcium binding sites which is essential for blood
clotting process.

Deficiency Symptoms of vitamin K
1. Haemorrhage in the new born is most common vitamin K
deficiency symptom. uncontrolled bleeding through nose
(epitaxis) and gastrointestinal tract is likely to occur. However
it can be treated successfully with intra muscular injections of
vitamin K.
2. In adults vitamin K deficiency rarely occurs. However
prolonged use of antibiotics may cause vitamin K deficiency
due to elimination of intestinal flora.

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