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Micronutrients
- Iodine
- Vitamin A
- Iron
- Zinc
- Folate
Micronutrients, so called because they are needed by the body
only in minute amounts, play leading roles in the production
of enzymes, hormones and other substances, helping to
regulate growth, activity, development and the functioning of
the immune and reproductive systems. Adequate intake is
especially crucial during early childhood and other periods
of rapid growth, pregnancy and breastfeeding.
The 1990 World Summit for Children singled out deficiencies
of three micronutrients — iron, iodine and vitamin A — as
being particularly common and of great concern for women and
children in developing countries. The Summit set goals for
the virtual elimination of iodine and vitamin A deficiencies
and the reduction of iron deficiency anaemia in women by one
third by the year 2000. Since then, knowledge of the
prevalence and importance of deficiencies of zinc and folate
have also been recognized. And more is being learned every
day about the importance of micronutrients for both the
physical and cognitive development of children.
Iodine
- Iodine deficiency is the single most important cause of
preventable brain damage and mental retardation. In pregnant
women it significantly raises the risk of stillbirth and
miscarriage. There is also evidence that severe iodine
deficiency increases women's risk of pregnancy-related death.
- An estimated 43 million people worldwide suffer from
varying degrees of brain damage and physical impairment due
to iodine deficiency, including 11 million who are cretins,
afflicted with profound mental retardation. Some 760 million
people have goitres, the swelling of the thyroid gland in the
neck that is the most common and visible sign of iodine
deficiency.
- Less severe iodine deficiencies in children and adults
can mean a loss of 10 intelligence quotient (IQ) points and
can impair physical coordination.
- The successful global campaign to iodize all edible salt
is reducing the risk of iodine deficiency, which threatened
1.6 billion people as recently as 1992. About 12 million
infants born in 1996 were spared that risk thanks to iodized
salt, and the number of babies born cretins is estimated to
have dropped by more than half, from 120,000 in 1990 to under
55,000 worldwide.
Vitamin A
- Over 100 million young children suffer from vitamin A
deficiency. It is a contributing factor in the 2.2 million
deaths each year from diarrhoea among children under five and
the nearly 1 million deaths from measles. Severe deficiency
can also cause irreversible corneal damage, leading to
partial or total blindness.
- Results of a dozen field trials in Brazil, Ghana, India,
Indonesia, Nepal and elsewhere indicate that supplementing
the diets of children at risk of vitamin A deficiency can
reduce deaths from diarrhoea. Four studies showed deaths were
reduced by 35-50 per cent. The vitamin can also reduce by
half the number of deaths due to measles.
- Vitamin A capsules cost roughly 2 cents each.
Supplementation reduces the risk of death of a child
deficient in vitamin A by 23 per cent. In 1997 alone, the
lives of at least 300,000 young children were saved by
vitamin A supplementation programmes in developing countries.
- Supplements of both vitamin A and zinc may boost
children's resistance to malaria, which kills 600,000 young
children each year, according to early evidence from a study
in Papua New Guinea. One third of children receiving vitamin
A had lower fevers due to mild to moderately high levels of
malaria parasites.
- Low-dose vitamin A supplements have been found to reduce
pregnancy-related deaths by an average of 44 per cent among
women in areas where deficiency is widespread, according to a
large-scale study in Nepal. The global toll of maternal
deaths is nearly 600,000 each year, the vast majority of
which are women in developing countries who die from largely
preventable causes. Yet scientists emphasize that high-dose
vitamin A supplements should never be taken by women of
childbearing age because of the potential risk of harm to a
developing foetus.
- A 1994 study of HIV-infected women in Malawi concluded
that vitamin A-deficient women were four and a half times
more likely to pass on the virus to their children.
Iron
- Iron deficiency anaemia, the most common nutritional
disorder in the world, lowers resistance to disease and
weakens a child's learning ability and physical stamina. It
is a significant cause of maternal mortality, increasing the
risk of haemorrhage and infection during childbirth.
- Nearly 2 billion people are estimated to be anaemic and
millions more are iron deficient, the vast majority of them
women. A range of factors cause iron deficiency anaemia,
including inadequate diet, blood loss associated with
menstruation and parasitic infections such as hookworm.
- A single dose of antiworm medicine costs as little of 3
cents and can eliminate or significantly reduce intestinal
worm infections, an important cause of anaemia.
- Fortifying foods with iron and providing iron
supplements are two approaches to addressing iron deficiency.
Fortification of wheat flour and flour products is being
promoted, particularly in Latin America and the Middle East,
where these foods are widely consumed. UNICEF is a major
supplier of iron/folate tablets, providing a total of 2.7
billion for pregnant women in 122 countries from 1993 to
1996.
Zinc
- Zinc promotes normal growth and development and is an
element in enzymes that work with red blood cells which move
carbon dioxide from tissues to lungs. It also helps maintain
an effective immune system. Zinc deficiency in malnourished
children contributes to growth failure and susceptibility to
infections, and is also thought to be associated with
complications of childbirth. There are, however, no data on
the prevalence of zinc deficiency. This deficiency usually
occurs where malnutrition is prevalent and is now recognized
as a public health problem in many countries.
- Trials in Bangladesh, India and Indonesia have shown
reductions of about one third in the duration and severity of
diarrhoea in children receiving zinc supplements and a median
12 per cent decline in the incidence of pneumonia.
- Zinc supplements helped blunt the most severe malaria
cases in children under age five, reducing by over a third
the number of such cases seen at health centres, according to
a study on zinc and vitamin A supplementation. Overall clinic
visits by those receiving zinc decreased by a third, and
signs of other infections were reduced by 20-50 per cent.
- The cost of a year's supply of zinc supplements for a
child is only $1.
- Zinc deficiency, increasingly recognized as widespread
among women in developing countries, is associated with long
labour, which increases the risk of maternal and infant
death. A number of studies have found that zinc
supplementation reduces complications of pregnancy.
Folate
- Folate is a B vitamin that helps in the formation of red
blood cells. Folate also regulates the nerve cells at the
embryonic and foetal stages of development, helping to
prevent serious neural-tube defects of the spinal cord and
brain.
- Folate deficiency causes birth defects in the developing
foetus during the earliest weeks of pregnancy — before most
women are aware that they are pregnant. It is also associated
with a high risk of pre-term delivery and low birthweight.
Folate deficiency also contributes to anaemia, especially in
pregnant and lactating women, and may be associated with
increased risk of maternal death and illness.
- UNICEF is a major supplier of iron/folate tablets for
pregnant women in developing countries, helping to reduce the
risks of folate deficiency for both mothers and infants.
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