Vitamin A Retinol for Healthy Eyesight

Vitamin A or retinol is found in foods of animal origin, while carotene is provided by foods of both plant and animal origin. Vitamin A can either be ingested or synthesized within the body from plant carotene. Those whose intake of vitamin A is only in the form of carotene should take a daily recommended amount as follows: Men: 2,400 mcg; Women: 2,400 mcg; Lactation: 3,800 mcg; Children: 1,600-2,400 mcg; Infants: 1,200 mcg. As a concentrated solution, retinol is light yellow in color. It solidifies when cooled and has a mild pleasant odour. It is insoluble in water or glycerol but soluble in most organic solvents. It is sensitive to oxidation by air in the presence of light.

Approximately 80% of vitamin A is absorbed in the human system. It is passed along with fat through the lymphatic system into the bloodstream. The absorption of vitamin A increases if it is taken with fats. Absorption is more rapid in men than in women. The absorption of this vitamin is poor in cases of diarrhoea, jaundice, and abdominal disorders. Vitamin A is stored in the liver. A healthy person can store about 97.2 mcg of vitamin A per gm of liver.
Approximately 20% of vitamin A which is not absorbed is excreted within one or two days into the faeces. Of the 80% absorbed, about 20% - 50% either combines with or burns down into products that are excreted within about one week in the faeces or urine. The remainder 30% - 60% of the absorbed vitamin A is stored.

Functions and Sources of Vitamin A

Vitamin A Deficiency Symptoms and Healing Properties and Precautions

Vitamin A for Eye Problems and Skin Disorders

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