VITAMINS

Vijayalakshmi

INTRODUCTION

organic molecules with wide variety of capacitiesprominent function - cofactors for enzymatic reactions generally cannot be synthesized by mammalian cells Vitamins are usually supplied in the diet or in dietary supplements necessary for our growth, energy, and general well-being

HISTORY

Ancient Egyptians recognized night blindness 1747-Scottish naval surgeon James Lind discovered the unknown nutrient (vitamin C) in citrus foods prevented scurvy

1753- Lind published his Treatise on the Scurvy 1860- Louis Pasteur demonstrated that microscopic organisms can cause diseases1880- Christian Eijkman

vitamin-deficiency conditions in animals on an experimental basis 1905- Julius Friedenwald and John Ruhräh

Beri-Beri is probably of microbic origin

1906- Frederick Hopkin's - foods contain a small amount of “growth factors” 1911- Casimir Funk discovered what he

termed "vitamines" 1919- “Eat and Be Healthy”, Virgil MacMickle, M.D., of Portland

“ chemical substances of which the body is composed are similar to those of the foods which nourish it. They are made up of the same chemical elements...the body can only get these from foods...”

FUNCTIONS

Digestion

Converting food into energy

Cell division and growth

Tissue repair

Transporting oxygen and wastes in the circulation

Immunity

FUNCTIONS

Mental alertness

Making hormones

Reproduction

Protecting the body from poisons

Neutralizing the harmful by-products of metabolism such as free radicals

CLASSIFICATIONWater soluble Fat soluble

  Thiamin (B1)

  Riboflavin (B2)

  Niacin (B3)

  Pantothenic acid (B5)

Pyridoxine (B6)

Biotin, Folic acid

  Cobalamin (B12)

Ascorbic acid

Vitamin A

Vitamin D

Vitamin E

Vitamin K

VITAMIN AVitamin A consists of three biologically active molecules, retinol, retinal and retinoic acidRetinol - “sticky” and light sensitive Provitamin A carotenoids – converted to retinol by the body ex- Beta (b)-carotene

Sources

milk, cheese, cream, liver, kidney, cod and halibut fish oil milk, Beta carotene - carrots, pumpkin, sweet potatoes, winter squashes, cantaloupe, pink grapefruit, apricots, broccoli, spinach and most dark green leafy vegetables

FUNCTIONS-VISION

isom eriza tion o f 1 1 -c is re tin a l toa ll-tran s re tin a l

1 1 -c is re tin a l g oes to rod ce llsan d b in d s w ith p ro te in

ca lled op s in to fo rmvisu a l p ig m en t ca lled rh od op s in

1 1 -c is re tin a l

1 1 -c is re tin o l

re tin yl e th e r

R E TIN O L

Immunity- maintains integrity of skin and mucosal cells - Development and differentiation of WBC- by

Retionic Acid- activation of t-cells requires all-trans RA binding

Growth and Development-embryonic development• Regulation of expression of gene for growth hormone

Red blood cell production DEFICIENCIES:

Night Blindness- Bitot’s spot, Xeropthalmia

infectious disease – Diarrhea, respiratory diseases

VITAMIN D

synthesized only when exposed to sunshine.Converted to active form, a,25-dihydroxyvitamin DThe a,25-dihydroxyvitamin D acts as a hormone, and has a specific nuclear receptor

SOURCES

Sunlight(PRIMARY)MILK PRODUCTS:Cheese, butter, margarine, cream, fortified milk SEA FOODS :fish, oystersfortified cereals.

FUNCTIONS:Calcium metabolism Vitamin D endocrine system - D3 bounds to vitamin D-binding protein and transported to liver- converted to 25-OH-D3 or calcidol (inactive)- increase exposure of sunlight – increase blood level of calcidol- hydroxyled to 1,25-OH-D3 or calcitriol- parathyroid hormone released

Vitamin D receptor – Vitamin D Receptor to Retinoic Acid X Receptor to form heterodimer-interacts with DNA

Vitamin D Responsive Elements - change in transcription of a nearby gene.

Cell differentiation- proliferation- psoriasis - the proliferation of skin cells called keratinocytes

- identification of VDR in keratinocytes led to the use of creams containing analogs of calcitriol in the treatment of severe cases of psoriasis.

Immunity – WBC recognizes Antigens- Autoimmune disease - Immune responses are mediated by T-Cells

DEFICIENCIES:RicketsOsteomalacia

VITAMIN K

The K vitamins exist naturally as K1 (phylloquinone) in green vegetables

K2 (menaquinone) produced by intestinal bacteria

K3 is synthetic menadione.

SOURCE

Spinach, cauliflower and other green leafy vegetables

chief source of vitamin K is synthesis by bacteria in the large intestine

FUNCTIONSCoagulation (clotting)

- ability to bind Ca2+ required for activation of the 7 “vitamin k-dependent” clotting factor in the coagulation cascade

- Factors II , VII, IX,X make up the core- Protein Z enhances the action of thrombin by promoting

association with phospholipids- Protein C and S control cascade- Vitamin k-dependent factors synthesized in liver

Bone mineralization – Osteocalcin – Osteoblasts- regulated by active form of vitamin D or calcitriol.

DEFICIENCIES

Liver disease

Poisoning with vitamin K antagonists

Hemorrhagic disease of the newborn results from vitamin K deficiency in human infants

Increased risk of fractures or reduced bone density may result from inadequate intake of vitamin K

VITAMIN E

Describes a family of 8 alpha, beta, gamma, delta and 4 tocotrienolsAlpha tocopherol is the only vitamin E that is actively maintained in human body found in tissues and bloodMaintains integrity of cell membrane and protects fats from oxidation

VITAMIN E

SOURCES:

Vegetable oils, nuts, egg yolk, Parmesan, chickpeas, wheat germ, oatmeal, olives,carrots, parsnips, red peppers, green leafy vegetables, sweet potatoes, tomatoes, sweet corn

DEFICIENCIES:Sever malnutrition

Genetic defects

Fat malabsorption

Neurological symptoms

VITAMIN B

THIAMIN B1

RIBOFLAVIN B2

NIACIN B3

PANTOTHENIC ACID B5

VITAMIN B6

TYPE FUNCTION

SOURCE

DEFICIENCY

B1

Thiamin pyrophosphate

Coenzyme

non – coenzyme function

Whole grains,

cereals, legumes nuts, lean pork, yeast

BERI-BERI

B2

Flavin mononucleotide

Flavin adenine dinucleotide

Oxidation-reduction (redox) reactions

Antioxidant functions

liver, eggs, cheese, milk and cereals

damage to eyes, mouth, and genitals

NIACIN

found in fish,poultry, meat, nuts and eggs

Niacin is required for the synthesis of of the active form of vitamin B3 NICOTINAMIDE ADENINE DINUCLEOTIDE

Deficiency disease is pellagra

VITAMIN B6

PYIDOXAL, PYRIDOXAMINE and PYRIDOXINE

Protein metabolism

Deficiencies are rare and usually related to overall deficiency of all the B-complex vitamins.

VITAMIN C

derived from glucose via the uronic acid pathway

extracted from plant sources such as rose hips, blackcurrants or citrus fruits

easily oxidised in air

SOURCES

Broccoli, Brussels sprouts, cauliflower, cabbage, mange tout, green leafy vegetables, red peppers, chilies, watercress, parsley, blackcurrants, strawberries, kiwi fruit, guavas, citrus fruit.

VITAMIN C

FUNCTIONS:synthesis of collagen, neurotransmitter, norepinephrine

protects indispensable molecules

regenerate other antioxidants such as vitamin E

DEFICIENCY:Scurvy