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A fat-soluble vitamin essential for vision, immunity and epithelial health, whose deficiency is the leading cause of preventable childhood blindness.
Vitamin A is a fat-soluble vitamin that the body needs for vision in dim light, for the health of epithelial tissues such as the cornea, skin and the lining of the gut and airways, for immune defence, and for growth and reproduction. It comes in two forms: preformed vitamin A, or retinol and its esters, found in animal foods such as liver, egg yolk, milk and fish liver oils; and provitamin A carotenoids, chiefly beta-carotene, found in carrots, pumpkin, mango, papaya and dark green leafy vegetables, which the body converts into retinol. Because it is fat-soluble, it is stored in the liver, so intake need not be daily — but for the same reason very large doses can accumulate and become toxic. Vitamin A deficiency remains a major public health problem among young children and pregnant women in India, which is why the government has run a national supplementation programme since 1970.
Type: ConceptTwo dietary forms — preformed vitamin A (retinol, retinyl esters) from animal foods, and provitamin A carotenoids such as beta-carotene from plant foods
Fat-soluble and stored in the liver, so it is absorbed along with dietary fat and does not need to be eaten every day
Essential for rhodopsin, the light-sensitive pigment in the rod cells of the retina that makes vision in dim light possible
Maintains epithelial tissue — including the cornea, which is why deficiency ends in blindness — and supports immune function
Deficiency progresses in stages: night blindness, then conjunctival dryness and Bitot's spots, then corneal damage and keratomalacia
Deficiency also raises the risk of death from measles and diarrhoea, so supplementation is a child-survival measure, not only an eye-health measure
Excess is dangerous too — hypervitaminosis A from very high doses of preformed vitamin A can damage the liver and harm a developing foetus, though beta-carotene from food does not cause this
Frequency: One of the most frequently asked nutrition topics in SSC, railway and banking general-awareness papers, and a standing theme in UPSC questions on nutrition programmes
Vitamin A does two different jobs in the eye. In the retina, retinol is converted into retinal, which combines with a protein to form rhodopsin, the pigment in rod cells that responds to dim light. When vitamin A runs short, rhodopsin cannot be regenerated fast enough and the person stops seeing in low light — night blindness, the first and fully reversible stage. Separately, vitamin A keeps epithelial surfaces moist and healthy. As deficiency deepens, the conjunctiva dries out and foamy grey patches called Bitot's spots appear, and then the cornea itself dries, ulcerates and can melt — keratomalacia. The cruelty of the sequence is that the first stage costs a few rupees of vitamin to reverse, while the last stage is permanent.
Think of rhodopsin as film in a camera that must be reloaded after every shot. Vitamin A is the film. Run out, and the camera still points at the scene but records nothing in low light — and if the shortage goes on, the lens itself clouds over for good.
1970 — National Prophylaxis Programme Against Nutritional Blindness
200,000 IU orally every six months to children aged 1-3 years
2006 — to children aged 6 months to 5 years
9 doses from 9 months to 5 years; first dose 100,000 IU with measles vaccination, then 200,000 IU every six months
About 60.5 per cent of children aged 9-59 months received a dose in the previous six months
Food Safety and Standards (Fortification of Foods) Regulations notified on 9 August 2018; '+F' logo on fortified packs
Edible oil and milk (with vitamin D); rice, wheat flour and salt carry other micronutrients
Biannual vitamin A rounds
States deliver mega-doses twice a year through health and anganwadi workers under the National Health Mission, which is why campaign months matter more than clinic visits for coverage
Fortified edible oil and milk
Because almost every household buys oil, adding vitamins A and D to it reaches people who never attend a supplementation round — the logic of fortification as a passive intervention
Golden Rice
Rice engineered to make beta-carotene in the grain, developed to address vitamin A deficiency in populations that eat milled rice as a staple — the standard example of biofortification in exam answers
Measles and vitamin A
WHO recommends vitamin A for children with measles because deficiency sharply raises the risk of severe illness and death, linking the vitamin to immunisation programmes
Ministry of Health and Family Welfare
Runs vitamin A supplementation through the National Health Mission
Food Safety and Standards Authority of India (FSSAI)
Sets fortification standards and administers the '+F' logo
POSHAN Abhiyaan
India's flagship nutrition mission, the umbrella for tackling malnutrition and micronutrient deficiency
World Health Organization
Recommends vitamin A supplementation for children aged 6-59 months in areas where deficiency is a public health problem
Vitamin A is fat-soluble (with D, E and K) and stored in the liver; retinol from animal foods, beta-carotene from plants
Functions: dim-light vision through rhodopsin, epithelial integrity, immunity, growth
Deficiency sequence: night blindness → Bitot's spots → corneal xerosis → keratomalacia; the leading cause of preventable childhood blindness
Deficiency also worsens measles and diarrhoea mortality — supplementation is a child-survival measure
India's programme began in 1970; widened to 6 months-5 years in 2006; 9 doses from 9 months to 5 years
First dose 100,000 IU with measles vaccine at 9 months; later doses 200,000 IU every six months
NFHS-4 coverage about 60.5 per cent of children aged 9-59 months in the previous six months
Fortification: 2018 FSSAI regulations, '+F' logo; edible oil and milk fortified with vitamins A and D; Golden Rice is the biofortification example
Too much preformed vitamin A is toxic (hypervitaminosis A) and harmful in pregnancy; beta-carotene from food is not
It is needed to make rhodopsin, the pigment that allows vision in dim light, and to maintain epithelial tissues such as the cornea, skin and gut lining. It also supports immunity and growth.
Night blindness first, then conjunctival dryness with Bitot's spots, and finally corneal damage and keratomalacia, which causes permanent blindness. Deficiency also increases deaths from measles and diarrhoea.
Liver, egg yolk, milk and fish liver oils supply preformed vitamin A. Carrots, pumpkin, mango, papaya and dark green leafy vegetables supply beta-carotene, which the body converts to retinol.
Children receive nine mega-doses between 9 months and 5 years — the first dose of 100,000 IU with the measles vaccine, then 200,000 IU every six months — delivered through the National Health Mission.
Yes. Because it is fat-soluble and stored in the liver, very high doses of preformed vitamin A can cause hypervitaminosis A, damaging the liver and harming a developing foetus. Beta-carotene from food does not carry this risk.