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.

3. 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?

5. 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

6. 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.

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

8. How they are classified??

9. 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

10. Fat soluble vitamins
• Soluble in fats and oils and in fat solvents
• All are isoprenoid compounds- one or more isoprene
units
• Isoprene units- CH2=C(CH3)-CH=CH2
• Diverse functions
• Vit K- coenzyme function

11. 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

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

13. A silent mind
sees better
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