Pharmacology for Dentistry

384 Section 10/ Vitamins and Trace Elements

FAT SOLUBLE VITAMINS

VITAMIN A

Vitamin A is widely distributed in plant
and animal foods. In plants, the main
source of vitamin A is green leafy
vegetables e.g. spinach and amaranth. The
darker the green leaves, the higher the
carotene present. Vitamin A is also present
in green & yellow vegetables and fruits e.g.
pumpkin, papaya and mango, and in roots
e.g. carrots (richest source among plant
source). The most important carotenoid is

betacarotene which has the highest vitamin

A percentage. Carotenes are converted to

vitamin A in the small intestine.

In animal foods, vitamin A is present in

liver, eggs, butter, cheese, milk, fish and meat.

Fish liver oil are the richest source of retinol.

It is vital for the functioning of retina.

Vitamin A is essential for differentiation

and growth of epithelial tissue. It enhances

function of immune system and protect

against development of certain malignan-

cies. Different forms of vitamin A mediate

different functions.

Table 10.1.2: Diseases due to deficient supply of vitamins.

Vitamins Deficiency

1. Vitamin A Night blindness (inability to see in dim light), conjunctival
   xerosis (dry and non-wettable conjunctiva), corneal xerosis
   (dry and non-wettable cornea and become opaque), kerato-
   malacia (cornea becomes soft and burst open and vision is
   lost), Bitot’s spots, growth retardation, dry and rough skin,
   sterility due to faulty spermatogenesis.


2. Vitamin D Rickets (reduced calcification of growing bones).


3. Vitamin E Axonal degeneration, ophthalmoplegia (however, vitamin E
   deficiency does not occur clinically).


4. Vitamin K Decreased prothrombin content of blood and blood clotting time
   is prolonged.


5. Vitamin B 1 (Thiamine) Beriberi (characterized by nerve involvement – peripheral neu-
   ritis), Wernicke’s encephalopathy (characterized by ophthalmo-
   plegia, polyneuritis and mental disorientation).


6. Vitamin B 2 (Riboflavin) Angular stomatitis (occurs in malnourished children).


7. Vitamin B 3 (Niacin or Nicotinic acid) Pellagra (characterized by diarrhoea, dermatitis and dementia).


8. Vitamin B 5 (Pantothenic acid) Clinical deficiency is not known (has role in biosynthesis of
   corticosteroids).


9. Vitamin B 6 (Pyridoxine) Peripheral neuritis, mental confusion, impairs the optimal
   utilization of pyridoxine [INH (anti TB drug) is a recognised
   antagonist].


10. Vitamin B 12 (Cyanocobalamin) Megaloblastic anaemia (pernicious anaemia), demyelinating
    neurological lesions in the spinal cord & infertility.


11. Vitamin C (Ascorbic acid) Scurvy


12. Folic acid Megaloblastic anaemia and gastrointestinal disturbances such
    as diarrhoea, distension and flatulence. Severe folate deficiency
    causes infertility or even sterility.