VITAMINS

VITAMINS

Introduction

Vitamins were discovered by Dutch physician, Christiaan Eijkmann, who won the 1929 Nobel prize in physiology and medicine. The word vitamin was derived from the term vitamine. The term "vitamine" was first used in 1912 by Dr. Casimir Funk, a Polish biochemist, in reference to substances that were vital to life and contained an amine.

Vitamins are a group of organic food substances or nutrients found only in living things, plants and animals.

Vitamins can be defined as naturally occuring organic substances which are required in minute amount to maintain normal health of the organism.

Vitamins are vital nutrients which helps our internal organs to work properly. We need vitamin in very small amount. Vitamins do not produce any energy but is essential for maintaining our health.

Vitamins are nutrients that found in food like, cereals, lentils, fruits and vegetables.

We need vitamins in very small amount and it helps in growth and for maintaining our health.

Vitamins are necessary in small amounts for normal metabolism and good health. Vitamins and minerals have no calories and are not an energy source, but assist in metabolizing nutrients in food and are invaluable in keeping your body running smoothly. Vitamins are sometimes referred to as the "spark plugs" of our human machine.

FUNCTIONS OF VITAMINS

Vitamins promote normal growth, provide proper metabolism, ensure good health and protect against certain diseases.

Vitamin is required by the body in small amounts for metabolism, to protect health, and for proper growth in children.

Vitamins assist in the formation of hormones, blood cells, nervous-system chemicals, and genetic material

Vitamins combine with proteins to create metabolically active enzymes that in turn produce hundreds of important chemical reactions throughout the body.

Vitamins are responsible for keeping cells strong, binding tissues, fighting infections, etc.

Vitamins help regulate metabolism, help convert fat and carbohydrates into energy, and assist in forming bone and tissue.

Vitamin A plays an important role in vision, bone growth, reproduction, cell division and differentiation.

CLASSIFICATION

Vitamins are divided into two classes based on their solubility.

The fat-soluble vitamins The water-soluble vitamins are vitamin A vitamin B12, vitamin D

vitamin B6, vitamin E biotin, vitamin K. niacin,

thiamin,

riboflavin,

pantothenic acid,

vitamin C (ascorbic acid)

DIFFERENCE BETWEEN FAT & WATER SOLUBLE VITAMINS

Fat soluble vitamin

soluble in fat

require bile salt & fat for

their absorption.

not excreted in urine.

generally stored in liver.

do not act as co-enzyme.

ex- A, D, E & K

Water soluble vitamin

soluble in water.

Easily absorbed.

They

Not stored in body except

vit.B12.

act as co-enzyme.

vit.B12 & vit.C

VITAMIN A (RETINOL)

OCCURANCE- Preformed vitamin A, or retinol, is found in:

Liver

Egg Yolk

Oily fish such as:  

HerringPilchards

Tuna

Sardines

Whole Milk .

Butter

Cheese

Good Sources of Beta Carotene include:

Carrots

Yellow and dark green leafy vegetables (e.g. spinach,

broccoli, watercress)

Herbs such as:  

Basil

Coriander

Parsley

Apricots

Pumpkin

Melon

Sweet Potatoes

Mango

Papaya

Red Pepper

Guava

Vitamin A is needed for new cell growth, healthy skin, hair, and tissues, and vision in dim light.

Recommended dietary allowances : 900 µg(male, age 19–70)

CHEMISTRY- IS DITERPENOID

STRUCTURALLY VIT. A IS CLOSELY RELATED TO PLANT PIGMANT CAROTENE (C40H56) WHICH EXIT IN DIFFERENT ISOMERIC FORMS.

CHEMISTRY

RetinolVitamin A is the collective name for a group of fat-soluble vitamins. The most useable form of the vitamin is retinol, often called preformed vitamin A as it is the active form in the body. Retinol (an alcohol) can only be found in animal sources and can be converted by the body into retinal (an aldehyde) and retinoic acid (a carboxylic acid), other active forms of vitamin A.Beta CaroteneBeta carotene, a hydrocarbon, is one of a family of dark pigments called provitamin A carotenoids, some of which can be converted to retinol by the body. In the liver, one molecule of beta carotene can be cleaved by an intestinal enzyme into molecules of retinol, so good food sources of beta carotene can also be good sources of retinol. The conversion of carotenoids to retinol will decrease when body stores are full thus preventing a retinol overdose, which can lead to toxic symptoms.

Fig.1 The Chemical Structure of Retinol

Fig.2 The Chemical Structure of Beta Carotene

BIOLOGICAL FUNCTION

It plays important role on vision, growth and development. We need vitamin A for maintenance of skin; hair and mucosal membrane of body .It also act as antioxidant, which required for neutralizing free radicals found in body and cause damage to body tissue

Vitamin A in the Body

Vitamin A is essential in the body for maintaining the immune system and vision and alsoforgrowth and tissue differentiation. It is also thought to aid prevention of cancer.

Vision

The retina of the eye is made up of light receptor cells, called rods, which allow us to 'see' light and dark. Within these cells is a pigment called rhodopsin which is a complex of opsin, a protein, and retinol. On exposure to light this complex disintigrates and releases electrical charges to the brain via the optic nerve. New rhodopsin is then formed from opsin and retinol.

.

. Immune System

Vitamin A aids health by maintaining the surface linings of the eyes and the intestinal, respiratory and urinary tracts, thus preventing bacteria from entering. It has also been suggested that vitamin A helps lymphocytes (a type of white blood cell) to function effectively, and that carotenoids may act as antioxidants in the body.

Tissue Differentiation

In the body there are many different cells with many different functions. The process by which a cell becomes a specific type of cell is called differentiation, and vitamin A is essential for differentiation of epithelial cells (i.e those of the skin, the mucous membranes, the cornea and the blood vessel walls).

DEFFICIENCY OF VIT. A

Deficiency of vitamin A can result in:

Night blindness - impaired vision in dim light.

Xerophthalmia - partial or total blindness due to damage of the cornea from a severe

deficiency.

Skin lesions.

Inhibited growth and bone development and loss of weight in the young.

Increased susceptibility to infection.

Keratomalacia an eye disorder that leads to a dry cornea. One of its major causes is Vitamin A deficiency.

Overdose diseaseHypervitaminosis A

VITAMIN D (CALCIFEROL)

Vitamin D has two main forms:

D2 (ergocalciferol)

D3 (cholecalciferol).

Vitamin D is a fat-soluble vitamin which is obtained either through the diet or simply by exposure to sun light. The human body can produce Vitamin D; sunlight creates a reaction producing vitamin D3 (cholecalciferol) which is then converted by the liver and kidneys into biologically active metabolites.

cholecalciferol(Vitamin D3)

SOURCES:

Vitamin D sources:

Vitamin D is found in

milk (fortified), cheese, whole eggs, liver, salmon, and fortified margarine.

The skin can synthesize vitamin D if exposed to enough sunlight on a regular basis.

FUNCTION

Prevents Rickets ( a childhood disease) - symptoms include malformed bones, bowed legs, late tooth development, listlessness.Regulates bone formation and repair.

VITAMIN E

Vitamin E:- ANTISTERILITY FACTOR

is a generic term for tocopherols and tocotrienols Vitamin E is a family of α-, β-, γ-, and δ- (respectively: alpha, beta, gamma, and delta) tocopherols and corresponding four tocotrienols. Vitamin E is a fat-soluble antioxidant that stops the production of reactive oxygen species formed when fat undergoes oxidation.

SOURCE

Excellent sources of vitamin E include

mustard greens, turnip greens, chard, and sunflower seeds.

Very good sources of vitamin E include

almonds and spinach.

Good sources of vitamin E include

collard greens, parsley, kale, papaya, olives, bell pepper, brussels sprouts, kiwifruit, tomato, blueberries, and broccoli.

Natural TOCOPHEROL exists as a mixture of 4 homologues, Alpha, Beta, Gamma, Delta - available as a mixed product known as MIXED TOCOPHEROL - which is also known as vitamin E. Riken Vitamin Co., Ltd. supplies TOCOPHEROL products and specialties according to requirements by separating or combining the homologues using unique technology.

 

Fig. 3The Chemical Structure of TOCOPHEROL

Homologues R1 R2 R3

Alpha- TOCOPHEROL

CH3 CH3 CH3

Beta- TOCOPHEROL

CH3 H CH3

Gamma- TOCOPHEROL

H CH3 CH3

Delta- TOCOPHEROL

H H CH3