Vitamin A is a fat-soluble vitamin that is important for better eye vision, immunity and also for proper growth, reproduction and fetal development.
There are 2 types of Vitamin A –
Preformed vitamin A – This is the active form of vitamin A that our body can use as it is! This form of vitamin A, also known as retinol, is found in animal products such as liver, fish, organ meat, etc.
Provitamin A – This is seen in plant-based products and needs to be converted into retinol (Preformed Vit-A) before being used by the body. Provitamin A is seen in plants in the form of an antioxidant called carotenoids
Most of the vitamin A in your body is kept in the liver in the form of retinyl esters to be used as and when required. Conversion of Provitamin (carotenoids) to the usable form – retinol is dependent on genetic factors, and overall health and may not be always efficient.
Liver meat, egg yolk, cheese, fatty fish, cod liver oil etc are rich sources of Retinol (Preformed Vit- A).
Carotenoids (ProVit-A) are anti-oxidants that give orange pigmentation to fruits and vegetables. They are seen in carrot, pumpkin, papaya, sweet potato, mango and other orange coloured fruits and vegetables
Recommended intake (RDA) of VitA is 700 – 900 mcg, while the upper limit is 3,000 mcg. Doses above 3,000 mcg on a regular basis can be toxic to the body.
Vit-A toxicity is often seen only with regular supplementation. Toxicity because of eating vit-A rich food is unheard of.