Key facts on vitamins and minerals
Iron Deficiency and Anaemia:
| Prevalence |
Risk factors |
Consequences |
| » |
Most common nutritional disorder
worldwide. |
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244 million people (46%) in Africa
suffer from anaemia. |
|
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Food intake: Low intakes of
meat/fish/poultry, high intakes of phytates (legumes, cereals); Low intakes of
Vitamin C, Allergy to cow's milk |
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Physiology: Preterm delivery or Low
birth weight; Pregnancy and adolescence - periods of high iron requirement;
Heavy menstrual losses |
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Infections: Parasite infections
(i.e. hookworm, schistosomiasis, ascaris) - which cause heavy blood losses;
Malaria (causes anaemia, not iron deficiency) |
|
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Anaemia |
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Increased risk of maternal
mortality and child mortality (severe anaemia) |
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Reduced cognitive performance
resulting in lower school performance, and 2.5% drop in future
productivity |
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Lower work performance and
endurance (5-17%) |
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Impaired iodine and Vitamin A
metabolism |
|
Vitamin A Deficiency:
| Prevalence |
Risk factors |
Consequences |
| » |
53 million (49%) preschool children
in Africa affected |
|
| » |
Low intakes of dairy products,
eggs, and ?-carotene from fruits and vegetables |
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Parasite infections (ascaris) |
|
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Increased risk of mortality in
children and pregnant women. Risk of death from childhood diseases increases by
as much as 23-40%. |
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Increases the risk of severe
illness and recovery time from common infections such as measles and
malaria |
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Increase clinic attendance and
health care costs |
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Leading global cause of preventable
childhood blindness |
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Night blindness, xerophthalmia |
|
Iodine Deficiency Disorders:
| Prevalence |
Risk factors |
Consequences |
| » |
260 million people (43%) in Africa
have insufficient iodine intakes |
|
| » |
Residence in areas with low levels
of iodine in soil and water |
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Living in high altitude regions,
river plains, far from sea |
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Consumption of non-detoxified
cassava |
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Consumption of non- iodised salt
|
|
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Birth defects |
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Increased risk of stillbirth and
infant mortality |
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Cognitive and neurological
impairment, including cretinism |
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Impaired cognitive functioning |
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Hypothyroidism |
| » |
Goitre |
|
Zinc Deficiency:
| Prevalence |
Risk factors |
Consequences |
| » |
Moderate to high prevalence in
Africa |
|
| » |
Low intakes of animal products |
| » |
High phytate intakes (cereals and
legumes) |
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Malabsorption and infection with
intestinal parasites |
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Diarrhoea, especially
persistent |
| » |
Genetic disorders |
|
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Non-specific if marginal
deficiency |
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Poor pregnancy outcomes |
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Impaired growth (stunting) |
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Lowered resistance to infections,
particularly diarrhea |
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Severe deficiency results in
dermatitis, retarded growth, diarrhea, mental disturbance, delayed sexual
maturation, recurrent infections |
|
B-Vitamin Deficiency Disorders:
| Prevalence |
Risk factors |
Consequences |
| Folate
(Vitamin B9) |
|
|
|
|
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Low intakes of fruits and
vegetables, legumes and dairy products |
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Malabsorption and intestinal
parasites |
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Genetic disorders of folic acid
metabolism |
|
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Megaloblastic anaemia |
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Risk factor for neural tube and
other birth defects |
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Elevated plasma homocysteine |
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Heart disease and stroke |
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Impaired cognitive function |
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Depression |
|
| Vitamin
B12 (Cobalamin) |
|
|
|
|
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Low intakes of animal products |
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Malabsorption from food due to
gastric atrophy or bacterial overgrowth |
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Genetic disorders of Vitamin B12
metabolism |
|
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Megaloblastic anaemia |
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Severe deficiency can cause
developmental delays, poor growth in infants and children, neurological
dysfunction |
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Risk factor for neural tube
defects, elevated plasma homocysteine and impaired cognitive function |
|
| Vitamin
B1 (thiamine) |
|
|
| » |
Insufficient data on
prevalence |
| » |
Regularly reported in famine
situations and among displaced populations |
|
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High consumption of refined rice
and cereals |
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Low intakes of animal and dairy
products, and legumes |
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Breastfeeding from deficient
mothers |
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Chronic alcoholism |
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Genetic disorder of thiamine
metabolism |
|
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Beriberi (severe deficiency)
presents in two forms: |
| |
Cardiac form, with risk of heart
failure (predominant in neonates) |
| |
Neurological, with chronic
peripheral neuropathy (loss of sensation and reflexes) |
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Wernicke-Korsakov syndrome (usually
in alcoholics) with confusion, lack of coordination and paralysis |
|
| Vitamin
B2 (Riboflavin) |
|
|
| » |
Insufficient data on prevalence,
likely to be very common in African countries |
|
| » |
Low intakes of animal and dairy
products |
| » |
Chronic alcoholism |
|
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Non-specific, can include |
|
Fatigue |
|
Eye changes |
|
Dermatitis |
|
Brain dysfunction |
|
Impaired iron absorption and
utilization |
|
| Vitamin
B3 (Niacin) |
|
|
| » |
Insufficient data on marginal
deficiency |
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Severe deficiency in form of
pellagra occur in parts of Africa, among displaced people and in famine
situations |
|
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Low intakes of animal and dairy
products |
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High consumption of refined
cereals |
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Maize-based diets (not lime
treated) |
|
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Severe deficiency results in
pellagra |
| » |
Dermatitis |
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Digestive mucosa disorders,
including diarrhea and vomiting |
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Neurological symptoms, depression,
memory loss |
|
| Vitamin
B6 |
|
|
| » |
Insufficient data on prevalence,
likely to be widespread in Africa |
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Typically associated with
deficiencies in other B-vitamins |
|
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Low intakes of animal products |
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High consumption of refined
cereals |
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Chronic alcoholism |
| » |
|
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|
|
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Non-specific symptoms, may
include |
|
Neurological disorders,
convulsions |
|
Dermatitis |
|
Anaemia |
|
Risk factor for elevated plasma
homocysteine |
|
Vitamin C (Ascorbic Acid) Deficiency:
| Prevalence |
Risk factors |
Consequences |
| » |
Insufficient data on moderate
deficiencies |
| » |
Severe deficiency (scurvy) occurs
in famine situations and among displaced people dependent on food aid for a
long time |
|
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Low intake of fresh vitamin C-rich
fruits and vegetables |
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Prolonged cooking of
vegetables |
|
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Severe deficiency results in scurvy
with bleedings gums, joint and muscle pain, peripheral oedema |
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Anaemia |
|
Vitamin D deficiency:
| Prevalence |
Risk factors |
Consequences |
| » |
Insufficient data on prevalence,
likely to be prevalent in some parts of Africa |
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More prevalent in at northerly or
southerly latitudes, where daylight hours are limited during winter months |
|
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Low exposure to ultra-violet
radiation |
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Wearing excess clothing |
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Having darkly pigmented skin |
|
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Rickets in Children and
Osteomalacia in adults |
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Linked to range of diseases and
health problems including cancer, multiple sclerosis, diabetes |
|
Calcium Deficiency:
| Prevalence |
Risk factors |
Consequences |
| » |
Insufficient data, low intakes very
common |
|
| » |
Low intakes of dairy products |
|
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Decreased bone mineralization |
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Increased risk of osteoporosis in
adults |
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Increased risk of rickets in
children |
|
For more information on vitamin and mineral deficiencies, see Allen, L,
De Benoist, B, Dary, O, and Hurrell, R (eds).
Guidelines on food fortification with micronutrients. 2006. WHO
and FAO. Geneva.
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