HEALTH MATTERS
IMPORTANCE OF
VITAMIN A
By Kepha Nyanumba
M
icronutrient deficiencies are
of great public health and
socioeconomic importance
worldwide. They affect low-income
countries but are also a significant
factor in health probl ems in
industrialized societies with impacts
among wide vulnerable groups in
the population, including women,
children, the middle-aged, and the
elderly.
derived from the diet.
months of losing their sight.
Deficiencies in micronutrients such
as vitamin A can have devastating
consequences. According to WHO,
Vitamin A deficiency is a public
health problem in more than half
of all countries, especially in Africa
and South-East Asia, hitting hardest
young children and pregnant women
in low-income countries.
Vitamin A is a fat-soluble vitamin
that is naturally present in many
foods. There are two different types
of vitamin A. The first type, retinoids
(retinol), is found in meat, poultry,
fish, and dairy products. The second
type, carotenoids (provitamin A) is
found in fruits, vegetables, and other
plant-based products.
Micronutrients are dietary
components, often referred to
as vitamins and minerals, which
although only required by the
body in small amounts, are vital to
development, disease prevention, and
wellbeing. Micronutrients are not
produced in the body and must be
Globally, 1 in 3 pre-school aged
children and 1 in 6 pregnant
women are vitamin A deficient due
to inadequate dietary intake. An
estimated 250 million preschool
children are vitamin A deficient with
half of vitamin A deficient children
who become blind dying within 12
The only type of vitamin A the body
can readily use is retinol. When you
get carotenoids (provitamin A) from
plant sources, your body must convert
the carotenoids into bioavailable
retinol.
‘‘Experimental studies in animal models,
along with epidemiological studies, have
shown that vitamin A deficiency leads to
immunodeficiency and increases the risk
of infectious diseases. Vitamin A and its
metabolites play critical roles in both innate
and adaptive immunity.’’
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There are a number of factors that
inhibit your body’s ability to absorb
carotenoids and convert them into
retinol. This includes genetics,
digestive problems, alcohol use,
certain medicines, toxic exposures,
and medical conditions that interfere
with the digestion of fat (including
cystic fibrosis, pancreatic enzyme
deficiency, and gallbladder and liver
disease).
What are the Signs of Vitamin A
Deficiency?