Ascorbic acid is essential for the production of collagenous or intercellular material which holds the cells in proper relation to each other. It is essential for healthy development of teeth, bones, cartilage and connective tissues.
It plays an important part in the healing of wounds and improves the ability to withstand stresses of injury and infection.
Vitamin C has many functions such as:
a) Antioxidant,(b) Collagen biosynthesis,(c) Oxidation of tyrosine,(d)Reduction of ferric iron into ferrous iron in the gastro-intestinal tract so that iron gets more readily assimilated by the body and (e) Conversion of folic acid into its active form, folinic acid.
Deficiency of Ascorbic Acid
Disease caused by deficiency of ascorbic acid is called Scurvy which is probably the oldest recognized deficiency disease.
The principal symptoms of scurvy are restlessness, loss of appetite, and general soreness to touch, sore mouth and gums with bleeding and loosening of the teeth, haemorrhages and swelling of the legs with problems about the knee joints. Anemia may occur as a result of the loss of blood.
Marginal symptoms of this disease are yellow skin, muddy complexion, lack of energy and pains in limbs and joints. Irritability, retarded, growth and tooth defects may also occur due to deficiency of vitamin C. Delayed healing of minor wound and pinpoint haemorrhages may also occur due to depletion of tissues.
A balanced diet for school children and adults should contain some 30-50 mg. of vitamin C per day.
Sources of Ascorbic Acid
Almost 100 per cent of the daily intake of ascorbic acid is obtained from the vegetables and fruits which is found in highest concentration in fresh fruits from the plant.
Fresh citrus fruits like lemon, orange, grape, amla, pineapple, guavas are excellent sources of Vitamin C. Spinach, green pepper, cabbage and turnip also contain good amount of vitamin C even when cooked.
Milk, egg and meat do not contain this vitamin. Human milk contains six times as much ascorbic acid as cow’s milk.
Warm environment, exposure to heat, solubility in water, alkalinity and dehydration destroy the ascorbic acid in the foods.
Vitamin C oxidizes enzyme present in the foods and therefore itself is responsible for the destruction of Vitamin C on exposure to air. It is active upon to 60o C, but after that it becomes inactive at higher temperature; therefore, cut fruits and vegetables should be consumed immediately. Even if these are to be cooked, they should be cooked in the water whenever the cooking temperature exceeds 60o C.