It is also known as retinol because it produces the pigments in the retina of the eye. vitamin ‘A’ is essential for growth and vitality. Vitamin A helps form and maintain healthy teeth, skeletal and soft tissue, mucous membranes, and skin. It builds up resistance to respiratory and other infections and works mainly on the eyes, lungs, stomach and intestines. It prevents eye diseases and plays a vital role in nourishing the skin and hair. It helps to prevent premature ageing and senility, increases life expectancy and extends youthfulness. The main sources of this vitamin are fish liver oil, liver, whole milk, curds, pure ghee, butter, cheese, cream and egg yolk, green leafy and certain yellow root vegetables such as spinach, lettuce, turnip, beets, carrot, cabbage and tomato and ripe fruits such as prunes, mangoes, papaya, apricots, peaches, almonds and other dry fruits. A prolonged deficiency of vitamin A may result in inflammation of the eyes, poor vision frequent colds, night blindness and increased susceptibility to infections, lack of appetite and vigour, defective teeth and gums and skin disorders.
The recommended daily allowance of vitamin A is 5,000 international units for adults and 2,600 to 4,000 international units for children. When taken in large therapeutic doses, which are usually 25,000 to 50,000 units a day, it is highly beneficial in the treatment of head and chest colds, sinus trouble, influenza and other infectious diseases . It is also valuable in curing night blindness and other eye diseases as well as many stubborn skin disorders. This vitamin can be given up to 1,00,000 units a day for a limited period of four weeks under doctors supervision.
The Food and Nutrition Board at the Institute of Medicine recommends the following:
(micrograms per day = mcg/day)
0 – 6 months : 400 mcg/day
7 – 12 months: 500 mcg/day
1 – 3 years : 300 mcg/day
4 – 8 years : 400 mcg/day
9 – 13 years : 600 mcg/day
Adolescents and Adults
Males age 14 and older : 900 mcg/day
Females age 14 and older : 700 mcg/day
Specific recommendations depend on age, gender, and other factors (such as pregnancy). Women who are pregnant or producing breast milk (lactating) need higher amounts.