Vitamin A influences human growth, improves skin condition, protects an organism from infection, promotes growth and development epithelial cells, is a part of visual pigment of eye rod cell, rhodopsin and visual pigment of cones – iodopsin. These pigments regulate dark adaptation of an eye. There is information about Vitamin A provides stable level of blood sugar helping an organism to use insulin more effectively. If this information is confirmed the use of retinol will become the first step to the victory over the resistance to insulin and such diseases as diabetes I and II types, hypertonia, hypoglycemia and fatness.

Mostly known symptom of hypovitaminosis of Vitamin A is so called “mooneye” that is a decline of sight when there is lack of light around. Lack of the vitamin leads to changes almost in all organs and systems of an organism. Excess of the vitamin causes stomach ache, monoschesis, hepatomegaly and splenomegaly, gastroenteric upset, hair loss, tingle, joint pain, sickness, vomit, clefts on the lips and in mouth corners.

The best sources of the vitamin are fish oil and liver, then it goes butter, egg yolk, cream and milk. Cereals and skim milk contain not enough of Vitamin A the same as beef.

However Vitamin A can be formed of some pigments in organism (in liver and intestine wall). The pigments are called carotenes, they are widespread in plants. The most active is b-carotene (provitamin A). It is considered that1 mg of b-carotene is as effective as 0.17 mg of Vitamin A (retinol). There is much of the carotene in apricots, dogrose, blackberries, yellow pumpkins, buckthorn, ashberries, water melons, red pepper, spinach, celery, parsley, fennel, lettuce, carrots, onions, green pepper, nettle, dandelion, clover.

Daily need in the vitamin for adults is 1 mg, for pregnant and nursing women – 1.25 – 1.5 mg, for children – 0.4 mg. The need increases while pregnancy, diabetes and liver disease.

Vitamin A can stand high temperature for short time. It is sensitive to oxygen and UVR
It is better to keep in dark place. It is steadier in food.

Vitamin A is better digested together with fat. Provitamin of Vitamin A is b-carotene which forms retinal and then retinol. Vitamin A is accumulated in liver.