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What roles does vitamin A play in vision, growth, and immunity?
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vitamin
Vitamin E in gel-cap form.
Vitamin A is a fat-soluble compound essential for several critical biological processes. Its roles in vision, growth, and immunity are summarized below:
- Vision: Vitamin A is vital for maintaining normal sight. In the retina, it is converted into retinal, which combines with the protein opsin to form rhodopsin. This light-sensitive pigment is necessary for dark adaptation and vision in low-light conditions.123
- Growth: Retinoic acid, a derivative of vitamin A, plays a key role in regulating embryonic development, cell differentiation, and normal tissue morphogenesis. It is essential for overall growth, and its deficiency can lead to growth retardation.13
- Immunity: Vitamin A is necessary for the proper functioning of the immune system. It helps maintain the integrity of epithelial tissues—such as the skin and the mucous membranes lining the respiratory and digestive tracts—which serve as the body's primary barriers against bacterial invasion and infection.23
Deficiency in this vitamin can lead to severe health issues, including night blindness, increased susceptibility to infectious diseases, and skin disorders.13