1. VITAMINS
BIOCHEMISTRY

2. Vitamins are micronutrients
Vitamins differ from macronutrients- in structure, function and amounts.
Vitamins are similar to macronutrients- all are vital to life, organic and available from all food group
Both defecienies and excesses of a vitamin can affect health

3. Vitamins µg-mg Nutrients /day VITAMINE VITAL+ AMINE
Vitamin is derived from the fact that substances are needed for life(vita) and because thiamine happened to be an amine.
Not all vitamins are amines or nitrogen containing compounds

4. Vitamins
Definition
Vitamins are organic nutrients that are required in small quantities for a variety of biochemical functions and which generally cannot be synthesized in the body and must be supplied by the diet

5. Water soluble Fat soluble Vitamins Classification B complex
C or Ascorbic acid
A or Retinol
D or Cholecalciferol
E or Tocopherol K

6. VITAMINS Water soluble vitamins B1 - Thiamine B2 - Riboflavin
B3 - Niacin
B5 - Pantothenic acid
B6 - Pyridoxine
Biotin
Folic acid
B12- Cobalamine
Vitamin B complex
Vitamin C or Ascorbic acid

7. VITAMINS Vitamins B-complex Energy-releasing Hematopoietic Other B1 B2
Biotin
Pantothenic acid
Folic acid
Vitamin B12
Pyridoxine

8. Difference b/w water soluble & fat soluble vitamins VITAMINS
Water soluble vitamins
Fat soluble vitamins
Solubility
Water soluble
Fat soluble
Absorption
Simple
Along with lipids
Storage
*No storage
Stored in liver
Excretion
Excreted
Not excreted
Excess intake
Nontoxic
Toxic
Deficiency
Manifests rapidly
Manifests slowly
Treatment
Regular dietary supply
Single large dose

9. Fat soluble vitamins
Vitamin A
Vitamin D
Vitamin E
Vitamin K

10. vitamin

11. Absorption, Transport and storage
VITAMIN A
Chemistry
Sources
Daily Requirements
Absorption, Transport and storage
Functions
Deficincy
Vitamin A excess
A. History.It was first recognized as an essential nutritional factor by Elmer McCollum in
1915 and then isolated from fish-liver oil by Holmes in On account of its established role
in the visual process, it is often called as antixerophthalmic factor or the “bright eyes” vitamin.
It was first synthesized in 1946 by Milas.

12. Vitamin A CHEMISTRY Retinoids Carotenes
Vitamin A occurs in two forms in food
Retinoids
Retinol
Retinal
Retinoic acid
Carotenes
α- carotene
β- carotene
γ- carotene

13. Retinoids
RETINOL
β-ionone ring
RETINAL
RETINOIC ACID

14. β- carotene

15. Vitamin a

16. Sources of vitamin A

17. sources

18. Recommended daily allowance [RDA]
The daily requirement of vitamin A is expressed as retinol equivalents [RE]
1000 RE
MEN
800 RE
WOMEN
1RE = 1µg of retinol
= 3.3 IU of retinol

19. ABSORPTION TRANSPORT AND STORAGE
VITAMIN A
ABSORPTION TRANSPORT AND STORAGE

20. ABSORPTION TRANSPORT AND STORAGE
RETINA
ABSORPTION TRANSPORT AND STORAGE
TARGET TISSUES

21. ABSORPTION TRANSPORT AND STORAGE

22. FUNCTIONS OF VITAMIN A Antioxidants :β -carotenes
Vision : 11-cis retinal [Wald’s visual cycle]
Reproduction: Retinol
Growth and differentiation : Retinoic acid
Epithelial Integrity : Retinol
Immunity
Antioxidants :β -carotenes
Glycoprotein synthesis

23. Vitamin A and Vision RODS RHODOPSIN 11-Cis retinal Opsin
Photoreceptor cells in the retina
Photosensitive pigment
11-Cis retinal
Opsin

24. Wald’s visual cycle Rhodopsin cycle comprises two distinct events
Bleaching of rhodopsin & generation of nerve impulse
Regeneration of rhodopsin

25. Wald’s visual cycle

28. Vitamin a and colour vision
CONES
Porphyropsin
Iodopsin
Cynopsin
Photoreceptor cells in the retina
Required for vision in daylight and colour identification

29. Vitamin a deficiency Causes Inadequate intake Impaired absorption
Impaired storage & transport
Increased excretion [RBP]
Alcoholism

30. Vitamin a deficiency Features Nightblindness Xerophthalmia Bitot spots
Keratomalacia
Infections
Hyperkeratinization of skin
Growth retardation

31. Bitot’s spot
Bitot’s spot

32. Xerophthalmia
Keratomalacia

33. Diagnosis of vitamin deficiency
Impaired dark adaptation time
Decreased vitamin A in plasma
Decreased RBP in plasma
Normal plasma vitamin
20 to 80 µg/100ml

34. Vitamin a toxicity Over ingestion Causes Bone and joint pain Anorexia
Hair loss
Headache
Hepatomegaly
Weight loss