Vitamin A deficiency

Key messages for primary care practitioners

  • Vitamin A deficiency is extremely rare in the indigenous UK population but is a serious public health concern in many low income countries, particularly in Africa and South East Asia.
  • Young children and pregnant women from low-income countries are most likely to be affected.
  • Practitioners should be alert to the possibility of vitamin A deficiency in at risk migrant patients and where they suspect it may wish to seek advice on appropriate diagnosis and management from their local endocrinology or paediatric team.
  • Vitamin supplementation should be considered for all infants from one month to five years, especially in at risk groups. Low income families in the UK who receive one of a range of income related benefits and tax credits may qualify for Healthy Start [external link].  Pregnant women, women with a child under one and children aged 6 months to their 4th birthday can get free Healthy Start vitamin supplements.  The supplements for children contain vitamin A.
  • Vitamin A has teratogenic effects in overdose and the Department of Health recommends that pregnant women, or women who may become pregnant should not be advised to take supplements containing vitamin A and should not eat foods rich in vitamin A such as liver and liver based products [1].

Background information

Symptoms

Testing and treatment

Prevention and control

Patient information (English only)

Other useful resources

References

Background information

  • WHO estimates that approximately one third of the world's school age population and 15% of pregnant women are biochemically vitamin A deficient. One percent of all children and 8% of all pregnant women are night blind as a result [2].
  • Vitamin A is an essential nutrient needed in small amounts (0.7mg a day for men, 0.6mg a day for women [3]) for the normal functioning of the visual system, and maintenance of cell function for growth and development, epithelial integrity (skin and mucous membranes), red blood cell production, immunity and reproduction [2,4,5].
  • Vitamin A is found in two forms: 
    • as retinol in foods from animal sources, such as whole eggs, milk, cheese and liver. In the UK fat spreads are also fortified with retinol. 
    • as carotenoids (mainly beta-carotene) in plant sources which are converted to retinol in the body e.g. green leaves, carrots, ripe mangos, and other orange-yellow vegetables and fruits.  
  • The main cause of vitamin A deficiency globally is a diet that is chronically deficient in the vitamin. Conditions associated with chronic diarrhoea can also reduce vitamin A absorption. Furthermore chronic or repeated infections can deplete physiological supplies. These factors may co-exist in people who are socio-economically disadvantaged.
  • Some research suggests that having more than an average of 1.5mg per day of vitamin A over many years may affect bone health and make them more likely to fracture as people get older.
  • Supplementation of smokers and subjects previously exposed to asbestos with beta carotene  has been associated with an increased risk of lung cancer. The mechanism for this effect is unknown but it seems likely that beta-carotene has a tumour promoting effect of some type. The EVM 2003 recommends that, as a matter of prudence, smokers or those exposed to asbestos should not take ß carotene supplements [6].

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Symptoms

  • Deficiency may be subclinical; children at risk include:
    • toddlers and preschool age children living at or below the poverty level 
    • children with inadequate health care or immunisations 
    • children living in areas with known nutritional deficiencies 
    • recent migrants or refugees from developing countries that have a high incidence of vitamin A deficiency and/or infectious disease  
    • children with diseases of the pancreas, liver, or intestines, or with inadequate fat digestion or absorption [5]
  • Clinical deficiency has numerous health consequences and children and pregnant women are most at risk as demands for vitamin A are higher during growth and pregnancy [7]:
    • Xerophthalmia - the leading preventable cause of blindness in children globally
    • Night blindness, especially during pregnancy when the additional metabolic demands cannot be met by a pre-existing marginal maternal vitamin A status 
    • Anaemia
    • Increased susceptibility to infections
    • Failure to thrive
  • Practitioners should be alert to the possibility of vitamin A deficiency in at risk migrant patients.

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Testing and treatment

Serum retinol is considered to be an insensitive measure of vitamin A status because it is buffered by retinol binding protein [6]. For the purposes of population surveys however serum retinol concentrations below 0.70 μmol/l are used as being indicative of vitamin A deficiency with severe deficiency below 0.35 μmol/l [2]. Although there is not yet international consensus, a serum retinol concentration below 1.05 μmol/l has been proposed to reflect low vitamin A status among pregnant and lactating women [2].

Treatment of vitamin A deficiency is generally based on diet and sometimes use of supplements (particularly for children with deficiency or for those with severe measles under two years of age where vitamin A has been shown to be effective in preventing serious complications). Practitioners should however be aware that vitamin A has toxic effects at high serum concentrations [6], particularly in pregnant women where teratogenic effects have been noted. Treatment with supplements should therefore be carefully monitored.

Vitamin A deficiency is extremely rare in the indigenous UK population and there are no standard UK guidelines for the diagnosis and treatment of vitamin A deficiency. Primary care practitioners who suspect vitamin A deficiency in a migrant patient may wish to seek advice on appropriate diagnosis and treatment from their local endocrinology or paediatric team.

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Prevention and control

The Department of Health recommends daily supplementary vitamin drops for all infants from one month to five years [8]. The Healthy Start [external link] Children's vitamin drops contain a combination of vitamins A, C and D and are available free of charge to children aged from 6 months to their 4th birthday in families who qualify for the Healthy Start Scheme [9].

NHS organisations may have local arrangements where they provide them free to those not on the scheme or at a small cost.

[Note that pregnant women or women who may become pregnant, who are not vitamin A deficient should be advised not to take supplements containing vitamin A (including fish liver oils), nor should they eat liver or liver products such as paté because of the risks of overdose and toxicity [1].]

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Patient information (English only)

Patient UK vitamin A leaflet [external link] 

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Other useful resources

NHS Choices advice on vitamin A [external link]  

Healthy Start [external link] - for information on vouchers for healthy food for children and pregnant women

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References

  1. Department of Health, Chief Medical Officer. Department of Health Press Release no 90/507. Women cautioned: watch your vitamin A intake. Department of Health, 1990.
  2. Global prevalence of vitamin A deficiency in populations at risk 1995-2005 [external link]. WHO Global Database on Vitamin A Deficiency. Geneva, World Health Organization, 2009  
  3. Report on Health and Social Subjects 41 'Dietary Reference Values (DRVs) for Food Energy and Nutrients for the UK', Report of the Panel on DRVs of the Committee on Medical Aspects of Food Policy (COMA) 1991.  Department of Health.
  4. British Nutrition Foundation: Vitamins [external link] 
  5. National Institutes of Health Office of Dietary Supplements. Dietary Supplement Fact Sheet: Vitamin A and Carotenoids [external link] 
  6. Expert group on vitamins and minerals 2003: Vitamin A (Retinol) [external link]
  7. World Health Organization. Micronutrient deficiencies: Vitamin A deficiency [external link]
  8. Department of Health. Birth to Five (2009 edition). Chapter 1: Feeding your baby [external link] 
  9. NHS Healthy Start website [external link]

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