Vitamin A was identified as a
necessary growth factor in 1915 and was the first vitamin to be discovered.
It is obtained from food in a combination of two different forms: as
pre-formed vitamin A and as pro-vitamin A, which the body can convert to
vitamin A as necessary. Pre-formed vitamin A, often in the form of retinal
or retinal, is found in foods of animal origin and pro-vitamin A, of which
beta-carotene is the best known form, is found in orange, yellow and dark
green vegetables and fruits. Both forms are fat soluble.
What does it do for your body?
EYES - Vitamin A is essential
for eyes to function effectively. It is involved in the growth and repair of
the eye and in the production of a chemical called visual purple, which
helps in night vision.
EPITHELIAL CELLS - Vitamin A is involved in the growth and repair of
epithelial cells. These cells cover the internal and external surfaces of
the body and are found in the skin, lungs, developing teeth, inner ear,
cornea of the eye, sex organs, glands and their ducts, gums, nose, cervix
and other areas. This growth and maintenance role is vital for many bodily
functions. For example, the good health of the digestive tract lining is
important in protecting against ulcers and maintenance of the lining of the
vagina and uterus is important in fertility.
PREGNANCY - Vitamin A is necessary in pregnancy for the development of the
NERVES - Vitamin A is involved in the production of membranes and of myelin,
which coats the nerves.
GLANDS AND HORMONES - Vitamin A plays a role in the maintenance of the
adrenal gland and synthesis of certain hormones such as thyroid hormone.
THE IMMUNE SYSTEM - Vitamin A is known as "the anti-infective vitamin" as it
is vital for the development of the body’s natural defenses. It stimulates
and enhances many immune functions. This immune enhancing function promotes
healing of tissues and increases resistance to infection.
Adequate vitamin A intake, either from diet or supplements, is very
important especially for children. Many studies have found that vitamin A
supplementation reduces the risk of infectious diseases in areas where
vitamin A deficiency is widespread. A recent research review of several
studies found that adequate vitamin A intake in children resulted in many
health benefits. Children in developing countries are often at high
risk of vitamin A deficiency. In developed countries, ensuring adequate
vitamin A intake is particularly important for immune support.
GROWTH AND BONE FORMATION - Vitamin A is necessary for growth and the
formation of bones and teeth, collagen synthesis, cartilage synthesis and
ANTIVIRAL ACTIVITY - Laboratory experiments have shown vitamin A to have