Vitamin k, vitamin E lecture3

Vitamin K,vitamin E, Brief introduction, their roles and diseases related to their deficiency

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Fat soluble VITAMINS Fat soluble VITAMINS
Vitamin KVitamin K

2. Learning objectives
Role of vitamin K regarding prothrombin formation
in liver.
Natural and synthetic form of vitamin K.
From where we get vit K naturally.
Daily requirement of vit K.
Deficiency symptoms of vit K.
Why generally recommend vit K inj to newly born
babies.
Toxic effect of high dose of vit K.
Chemistry, functions, deficiency and daily
requirement of Tocopherol.

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Vitamin K
Vitamin K is essential for the formation of
prothrombin couple in the liver & therefore
maintaining the normal prothrombin level in
the blood.
It exist in several forms, for example, in plants
as phylloquinone (vitamin K1), & in intestinal
bacterial flora as menaquinone (vitamin K2).
A synthetic form of vitamin K3 – menadione.
Vitamin K

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Structures of vit K

C11H8O2C11H8O2
Vitamin K1 Vitamin K2
Vitamin K3 (Menadione)

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Source Source
In plants (vit K1) it is chiefly present in green in green
leafyleafy tissues (alfalfa, spinach), also found in
cauliflower, cabbage, tomatoes, soya beans,
rice etc.
In human alimentary canal, it is synthesized
by intestinal floraintestinal flora & endogenously supplied to supplied to
the bodythe body.

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Requirement: Requirement:

120 120 μμg/dayg/day for adult males & 90 90 μμg/dayg/day for
adult females.

Functions of vit K:Functions of vit K:
Vit K is required in the hepatic synthesis of
prothrombinprothrombin & blood clottingblood clotting factors II, VII,
IX & X.

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Deficiency of vit k (Hypovitaminosis)Deficiency of vit k (Hypovitaminosis)
A true vit k deficiency is unusualunusual because
adequate amountsadequate amounts are generally produced by
intestinal bacteriaintestinal bacteria or obtained from the dietdiet.
In case of chemotherapy (antibioticsantibiotics) amount
of vit K is depressed, that can lead to
hypoprothrombinemia in malnourishedmalnourished
individual, e.g: a debilitated geriatric patient.
Newborns have sterile intestinesterile intestine which lack the
bacteria that synthesize vit K. So, it is
recommended that all newbornsall newborns receive a
single IM dosesingle IM dose of vit K as prophylaxisprophylaxis against
hemorrhagic disease.

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Hypervitaminosis Hypervitaminosis
Prolonged administration of large doses of
synthetic vit K (menadione) can produce
hemolytic anemiahemolytic anemia & jaundicejaundice in the infant, due
to toxic effects on RBCstoxic effects on RBCs; therefore, it is no no
longer usedlonger used to treat vit K deficiency.
Normal Hemolytic anemia Jaundice

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Vitamin E

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Vitamin E (TocopherolTocopherol)
The vitamin E consist of eight naturally eight naturally
occurringoccurring tocopherols, of which α-tocopherol
is the most activemost active.
They are commercially important, as they are
antioxidantantioxidant for fats, oils, vitamin A &
carotenes.

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Structural formula of a-tocopherol

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Occurrence
Plant source: All green plantsgreen plants contain
considerable amount of tocopherols. Vegetable Vegetable
fatsfats are the richestrichest naturalnatural source (wheat germ
oil).
Legumes, nuts, cereals are also important
source.
Only a small amountssmall amounts are present in olive &
coconut oils.
Animal tissue contain relatively less amounts.
Milk is poor in this factor.

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Requirements of vit E:
The RDA for α-tocopherol is 15mg15mg for adults.
The vit E requirement increasesincreases as the intakeintake
of polyunsaturated fatty acidpolyunsaturated fatty acid increases.
Deficiency of Vit E:
In human – not takes placenot takes place due to its wide
occurrence in vegetablevegetable.
Vit-E deficiency may be found in
lipoproteinemialipoproteinemia & in diseases such as sprue,
obstructive jaundice etc.

14. Vit E deficiency in adults, is usually associated
with defective lipid defective lipid absorption or transport.
The signs are; sensitivitysensitivity of erythrocytes to
peroxide, & the appearance appearance of abnormal
cellular membrane.

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Functions
Vit E participates in the formationformation of
intercellular substance, collagencollagen & elastic elastic
fibersfibers derived from it.
It is important antioxidantantioxidant & protectprotect easily
oxidizable vit A. Tocopherols are usually
added to commercial oily foodscommercial oily foods to prevent
their oxidation.
Vitamin E Prevents massive hepatic necrosishepatic necrosis
produced on diet deficient in Sdeficient in S containing
amino acids.

16. It protects lungs tissueslungs tissues from polluted air.
Also protects & stabilizes the cell membranecell membrane.
 Vitamin E also takes part in the synthesis of synthesis of
hemeheme.
More recent functions are its curative action
on menopausal disordersmenopausal disorders, male sterilitymale sterility &
prurituspruritus etc.
“Every healthy person, after 45 yrsafter 45 yrs must take
vit-E daily to prevent heart attackheart attack & to retard
agingaging processprocess”.

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References & keys

Mushtaq Ahmad vol-IIMushtaq Ahmad vol-II

Hashmi’s Textbook of Medical BiochemistryHashmi’s Textbook of Medical Biochemistry
Debilitate = weak
Geriatric: old age people
Sprue: tropical disease - deficiency of nutrients absorption from intestine,
diarrhoea, enemia.
