Advice and guidance on the health needs of migrant patients for healthcare practitioners.
Vitamin A deficiency is extremely rare in people born in the UK, but is a serious public health concern in many low income countries, particularly in Africa and South East Asia.
Vitamin A deficiency particularly affects young children and pregnant women from low-income countries as it is :
- a major cause of preventable bchoilindness in children and increases the risk of disease and death from severe infections
- causes night blindness in pregnant women and may increase the risk of maternal mortality especially in the third trimester
Consider vitamin A deficiency in at-risk migrant patients. Where you suspect it, seek advice on appropriate diagnosis and management from your local endocrinology or paediatric team.
Consider vitamin supplementation for all infants and children under five years old.
Low-income families in the UK who receive one of a range of income-related benefits or Child Tax Credits may qualify for Healthy Start. Children between six months and four years old may also qualify for free Healthy Start vitamin supplements which contain vitamin A.
However, advise pregnant women or women who may become pregnant to avoid vitamin A supplementation and foods rich in vitamin A, such as liver and liver based products, because vitamin A intake over a certain amount may have teratogenic effects.
WHO estimates that approximately one third of pre-school aged children and 15% of pregnant women (at risk of deficiency) are biochemically vitamin A deficient globally. Vitamin A deficiency is one of the leading preventable causes of blindness in children globally.
The number of people who are night blind as a result is approximately:
- 1% of all children
- 8% of all pregnant women
The main cause of vitamin A deficiency globally is a diet that is chronically deficient in vitamin A. This deficit is exacerbated by high rates of infection especially diarrhoea can also reduce vitamin A absorption and repeated infections can deplete physiological supplies which becomes most apparent at stages of high nutritional demand such as early childhood, lactation and pregnancy. These factors may co-exist in people who are socio-economically disadvantaged.
Vitamin A is an essential nutrient needed in small amounts for:
- normal functioning of the visual system
- maintenance of cell function for growth and development
- epithelial integrity (skin and mucous membranes)
- red blood cell production
The daily amount of vitamin A needed by adults is:
- 0.7mg a day for men
- 0.6mg a day for women
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.
At Risk Groups
- premature infants
- Infants and young children in low-income countries (including infants who are exclusively breastfed by vitamin A deficient mothers)
- pregnant and lactating women in low-income countries
- people with cystic fibrosis
- recent migrants or refugees from low-income countries that have a high incidence of vitamin A deficiency and/or infectious disease
- children with inadequate health care or immunisations
Infants, children and pregnant women are most at risk as demands for vitamin A are higher during growth and pregnancy.
Forms of vitamin A
Vitamin A is found in 2 forms: retinol and carotenoids.
Vitamin A is essential to the normal structure and function of the skin and mucous membranes. It is vital for vision, embryonic development, growth and cellular differentiation and the immune system.
Retinol occurs in foods from animal sources, such as:
- whole milk
It is also voluntarily added to some fat spreads.
Carotenoids (mainly beta-carotene) occur in plant sources which are converted to retinol in the body, for example:
- green leafy vegetables
- mangos and other orange-yellow vegetables and fruits
Deficiency may be subclinical. However clinical deficiency has numerous health consequences including:
- xerophthalmia (dry eyes) - an early sign of chilhood blindness
- night blindness and/or longer vision restoration levels in different ambient light settings
- anaemia (as those with vitamin A deficiency also tend to have low iron)
- increased susceptibility to infections
- increased severity and mortality from infections
Be alert to the possibility of vitamin A deficiency in at-risk migrant patients.
Testing and treatment
Serum retinol is not useful for assessing the vitamin A status of individuals as it is not always correlated with intake or clinical signs of deficiency. Serum retinol is homeostatically controlled, unless liver vitamin A stores are either:
- severely depleted (<0.70 μmol/l)
- very high (>1.05 μmol/l).
It is only at these extremes that the serum retinol level reflects the liver Vitamin A stores
In population studies however, the distribution of serum retinol values and the prevalence of individuals with serum retinol values below 0.70 μmol/l (indicative of vitamin A deficiency) and 0.35 μmol/l (severe deficiency) can provide useful information.
Although there is no international consensus as yet, a serum retinol concentration below 1.05 μmol/l has been proposed to reflect low vitamin A status among pregnant and lactating women.
Treatment of vitamin A deficiency is generally based on a Vitamin A rich diet, and the use of supplements, particularly for children with deficiency or for those with severe measles under 2 years of age, where some studies have found vitamin A to be effective in preventing serious complications.
Vitamin A has toxic effects at high serum concentrations, particularly in pregnant women. Excessive supplementation in pregnant women, can be teratogenic.
Vitamin A deficiency is rare in people born in the UK, but low intakes are relatively common 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.
Prevention and control
The Department of Health recommends daily supplementary vitamin drops for all infants and children under 5 years. If infants are drinking 500ml of infant formula a day supplements may not be needed.
Healthy Start 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.
NHS organisations may have local arrangements where they provide vitamins free, or at a small cost, to those not on the scheme.
- not to take supplements containing vitamin A (including fish liver oils) as they might be teratogenic
- not to eat liver or liver products, such as paté, as they may contain high levels of vitamin A
Patient.co.uk has produced a leaflet on vitamin A.
NHS.UK has more information about vitamin A.
Healthy Start has information on vouchers for healthy food for children and pregnant women.