Vitamins are important nutrients for the normal maintenance of the body functions and immunity.
Vit A is a fat soluble vitamin, which can be obtained either as a preformed vitamin, or as retinols, which are converted in the body to the active vitamin A. Retinols are found in green vegetables and orange fruits, while vitamin A is found animal sources like fish, eggs, and liver. In breast fed infants, the daily requirements of vitamin A are provided by the breast milk. However, once weaning begins, the diet needs to be fortified with vitamin A.
Vit A plays a major role in maintaining the barrier integrity, in T cell lymphopoiesis, and CD4 T lymphocyte production. The pro inflammatory cytokine Gamma interferon and IL2 levels is decreased by IL10, normally. However, in Vit A deficiency states, the IL10 production is decreased, resulting in increased susceptibility to infections. In a meta-analysis of 20 controlled trials, it was found that the supplementation of vitamin A in the diet significantly decreased the mortality and morbidity among children in the developing countries
Vit A absorption maybe affected in case of malabsorption states. Dietary supplementation ensures protection against recurrent infections, aids in faster recovery and decreased complications after measles and gastroenteritis, and ensures optimal growth and development of the nervous system in children, particularly ocular maturation. Vit A is very important for the development of normal fucntions of the rods and cones of the eyes. Any deficiency of this vitamin will result in night blindness and altered color vision.
Vit C is a powerful antioxidant, which is essential for the normal formation of bones, collagen and intercellular tissues. Vit C is obtained from fruits and juices, citrus fruits and gooseberry being a rich source of vitamin C.
Vit C is a powerful antioxidant, and plays a vital role in the immune system .It affects the functions of the proliferation of neutrophils, the phagocytes and adhesion molecules of monocytes .As a powerful antioxidant, the vitamin C protects the host from the adverse effects of the oxidants released by the invading microorganisms. Controlled trials have shown lower incidence of pneumonia and lower respiratory infections when vit C levels have been supplemented in the diet. Studies conducted at Quebec, Canada also show low levels of Vit C in the approximately 20% of the population, who thus require supplementation in their diet
Long standing Vitamin C deficiency causes Scurvy, which is commoner in younger children with inadequate supplementation during weaning. It is characterized by painful subcutaneous bleeds, joint bleeds, bleeding gums etc, due to the capillary damage. Untreated scurvy can result in joint deformity and locomotor disabilities.
Sources of Vit A & C :
Vit A is found in fish oils, especially the oily fish like mackerels, tuna, salmons etc. Egg is a rich source of Vit A. Besides these, this vitamin is rarely found in vegetarian sources. Hence, it needs to be supplemented in those who consume a totally vegetarian diet.
Vit C is found in citrus fruits like lemons, oranges as well as guavas, gooseberry and kiwi fruit. It is a good idea to include at least some of these in the diet regularly, to prevent deficiency