Antibiotics, laxatives money, drugs that inhibit the absorption of fat in the gastrointestinal tract (some funds to reduce weight) and medications that reduce blood cholesterol, affect the absorption of vitamin A. In recent years, The direct dependence of retinol deficiency on the duration of sun exposure, especially for people living in the middle and northern latitudes, leaving for vacation in southern countries. Vitamin A and retinol vision deficiency can cause night (twilight), and in some cases, total blindness. Vitamin A ensures the existence of normal cells of the mucous membranes eyes. Hallmarks for the failure of retinol is xerophthalmia (dry eyes). When added to the diet of patients of vitamin A for xerophthalmia improves. Proved that vitamin A prevents the development of night blindness, saves eyesight, especially the twilight and night.
It Retinol helps eyes adjust when moving from bright light into the darkness. If there is insufficient vitamin A growing day-blindness – "Night blindness" – the deterioration of twilight and night vision. Vitamin A and immunity in retinol deficiency reduces the body's resistance to infections. This is due to atrophic changes and the depletion of T-zones. Experiments have shown that vitamin A has a stimulating effect on various of the immune response.
Retinol provides the formation of immune (protective) cells lining the respiratory tract and gastrointestinal tract, serving as a natural barrier to the penetration of the infection. When avitaminosis vitamin A deficiency there is increased susceptibility to infection. Enhancing immunity, retinol significantly improves resistance to infectious diseases, including, for colds, flu, flu and bronchitis.