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VITAMIN E�VITAMIN K

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Dr. Ashish Agravatt, MBBS, MD.

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VITAMIN E [TOCOPHEROL]

Chemistry

Sources

RDA

Metabolism

Functions

Deficiency

Toxicity

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VITAMIN E - CHEMISTRY

Tocopherols

α-tocopherol

β-tocopherol

γ-tocopherol

δ-tocopherol

Tocotrienols

α-tocotrienols

β-tocotrienols

γ-tocotrienols

δ-tocotrienols

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VITAMIN E - CHEMISTRY

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Vitamin E

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Dietary Sources

  • Cottonseed oil, cord oil, wheat germ oil and mergarine.
  • Soyabeans, Cabbage, Yeast, Apple seeds, Peanuts.

Daily Requirement 1 mg of α-Tocopherol = 1.49 I.U

Children = 10 – 15 IU/day Adult = 20 – 25 IU/day ↑ in pregnancy and lactation

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VITAMIN E – SOURCES

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VITAMIN E – RDA

RDA

8 – 10 mg/day

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The daily requirement increases with increase in dietary intake of PUFA

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VITAMIN E – METABOLISM

Absorption

Upper SI

Along with lipids

Transport

Chylomicron

VLDL and LDL

Storage

Adipose tissue

liver

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VITAMIN E – FUNCTIONS

As a biological antioxidant

Prevents lipid peroxidation of biological membrane

Prevents peroxidation of vitamin A & PUFA

Reproductive functions & prevents sterility

Vitamin E

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VITAMIN E – FUNCTIONS

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Function of Vitamin- E

  1. Antioxidant property

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Cell membrane

PUFA-H Polyunsaturated FA

PUFA-OO° Peroxyl free radical of PUFA

PUFA-OO°

PUFA-OOH

Toc.OH

(α-tocopherol)

Toc.O°

(free radical of α-tocopherol)

Vit C (OX) or GSSH

Vit C (Red) or GSH

R°

Free radical (Initiator of chain reaction)

I

II

III

O2

H

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(2) Role in reproduction

  • Vitamin- E helps in maintaining seminiferous epithelium intact. Deficiency leads to permanent sterility. Motility of sperm is lost and spermatogenesis is impaired.
  • In female ovary is unaffected by vitamin- E deficiency but foetus does not develop normally dying in utero.

(3) Other function

  • Synthesis of coenzyme Q or Udiquinone.
  • Role in nucleic acid synthesis.

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VITAMIN E & SELENIUM

Selenium complements the antioxidant effects of vitamin E and reduces the requirement of vitamin E

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VITAMIN E - DEFICIENCY

Causes

Inadequate intake

Impaired absorption

Features

Hemolytic anaemia in the new born

Muscle weakness

Spinocerebellar ataxia and impaired vision

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Deficiency of Vitamin- E

  1. Muscular dystrophy
  2. ↑ oxidation of PUFA.
  3. Consequent rise in O2 consumption and peroxide production.
  4. Peroxide cause ↑ in hydrolase activity. Hydrolase breakdown in muscle give rise to muscular dystrophy.

(2) Hemolytic Anemia

↓ Vitamin-E in diet

↓ Plasma Vitamin-E

↑ Susceptibility to hemolysis due to peroxide

HEMOLYTIC ANEMIA

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(3) Low Vitamin- E

Lipoproteinemia and disease like obstructive jaundice, Pancreatitis, Steatorrhoea.

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Clinical & Therapeutic use

  • Nocturnal muscle cramps (NMC)
  • Intermittent claudication (IC)
  • Fibrocystic breast disease (FBD)
  • Atherosclerosis

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VITAMIN K

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VITAMIN K - CHEMISTRY

Pylloquinone

Present in plants

Vitamin K1

Menaquinone

Produced by intestinal bacteria

Vitamin K2

Menadione

Synthetic form

Vitamin K3

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VITAMIN K - SOURCES

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VITAMIN K - RDA

80µg/day

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VITAMIN K - METABOLISM

Absorption

Upper SI

Along with lipids

Transport

Chylomicron

LDL

Storage

Liver

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VITAMIN K - FUNCTIONS

Role in blood coagulation

    • Cofactor for gamma carboxylation of glutamic acid in clotting factors II, VIII, IX and X

Role in bone mineralization

    • Cofactor for gamma carboxylation of glutamic acid in osteocalcin

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VITAMIN K - DEFICIENCY

Causes

In newborn

Impaired absorption

Sterile bacterial flora

Features

Bleeding

Prolonged prothrombin time

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VITAMIN K - ANTAGONIST

Dicumarol

Warfarin

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VITAMIN K - ANTAGONIST

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