Introduction to Vitamins

The history and overview of vitamins and their classifications that gives a glimpse to the requirement and clinical significance of vitamins in Medical Science

1. Vitamins Prof. (Dr.) Viyatprajna Acharya, M.D.

2. LEARNING OBJECTIVES Why Vitamins? What are they? How they were found? Where found? Are they all same? Why know in medical science?- Clinical significance How they are important in metabolism? Where else they are required?

3. How they were found??? Ancient Greece- liver dipped in honey cured night blindness The ‘limeys’ 1912- Hopkins “ accessory factors” 1913- Casimir Funk “ Vitamine ”- initially discovered vitamins contained amino group 1915- Mc Collum & Davis named as A,B, C … 1930- Final classification of vitamins   Kazimierz Funk

4. What are vitamins??? Chemically unrelated organic compounds Can’t be synthesised adequately by humans Must be supplied in diet Defn : Vitamins may be regarded as organic compounds required in the diet in small amounts to perform specific biological functions for normal maintenance of optimum growth an health of the organism.

5. Intestinal bacteria synthesises few vitamins B vitamins and K Antibiotics kill them Hence vitamins are prescribed along with

6. How they are classified??

7. Fat soluble Vs Water soluble vitamins Fat soluble Water soluble Solubility in fat + Water solubility + Absorption Along with lipids; need bile salts *Simple Carrier proteins Present *Nil Storage In liver *No storage Excretion Not excreted Excreted Deficiency Seen when stores are depleted *Rapidly manifests Toxicity Hypervitaminosis Unlikely Tt of deficiency Single large dosage may prevent Regular dietary supply is required Major vitamins A, D, E & K B complex & C ** Vit B12 is an exception

8. Fat soluble vitamins Soluble in fats and oils and in fat solvents All are isoprenoid compounds- one or more isoprene units Isoprene units-  CH 2 =C(CH 3 )-CH=CH 2 Diverse functions Vit K- coenzyme function

9. Water soluble vitamins Need to be supplied continuously in diet Usually vitamin deficiencies are multiple rather than individual Overlapping symptoms Mostly coenzymes- energy generation or hematopoiesis Rapidly dividing tissues manifest the deficiency manifestations B1, B6, B12- neurological manifestation

10. Vitamers Chemically similar substances that possess qualitatively similar vitamin activity Vitamin A- Retinol, retinal & retinoic acid Vitamin B6- Pyridoxine, pyridoxal and pyridoxamine

11. A silent mind sees better www.vpacharya.com