Vitamin A is a group of fat-soluble compounds that can be differentiated into two categories,
depending on whether the food source is an animal or a plant:
Vitamin A found in foods that come from animals is called ’preformed vitamin A’ or ’retinol’; it is
one of the most active forms of vitamin A.
Vitamin A found in fruits and vegetables is called ’provitamin A carotenoid’, which can be
cleaved into retinol in the body; the carotenoid ’beta-carotene’ is most efficiently converted into
retinol, making it an important vitamin A .
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Functions
A sufficient vitamin A (retinol) intake is essential for
the process of vision (especially night vision)
growth and development – it is involved in the genetic regulation of cell and tissue
formation, programming, and communication needed for reproduction and for the proper
development of the embryo in the womb
immune function – it helps to protect against infections by ensuring the effectiveness of
mechanical barriers (e.g., skin), and increasing the production and efficacy of protective cells
(e.g., lymphocytes)
male and female reproductive organs.
The European Food Safety Authority (EFSA), which provides scientific advice to assist policy
makers, has confirmed that clear health benefits have been established for the dietary intake of
vitamin A in contributing to:
normal cell differentiation;
a normal development and function of the immune system;
the maintenance of normal skin and mucous membranes;
the maintenance of normal vision;
normal iron metabolism.
Deficincy
Vitamin A deficiency usually results from inadequate intake of foods high in vitamin A or
beta-carotene, a precursor of vitamin A. The earliest symptom of vitamin A deficiency is night
blindness. Groups at risk for insufficient vitamin A supply are mainly pregnant and
breast-feeding women, newborns, children with frequent infections, the elderly and people who
avoid animal-derived foods.