Background

Vitamin A is a fat soluble vitamin that is required for vision, immune function, growth and maintenance of epithelial cells.[1] Infants accumulate stores in the 3rd trimester of pregnancy and rely on breast milk for supply. Vitamin A is measured in retinol equivalents . Foods contain both retinol and vitamin A precursors (carotenoids), which can be converted to vitamin A.

1 retinol equivalent (RE)

1 mcg retinol 6 mcg beta-carotene 12 mcg other provitamin A carotenoids

3.33 IU vitamin A (from retinol)

WHO recommends supplementation in high risk* children and women post-partum to prevent vitamin A deficiency.[6, 7] Vitamin A deficiency is associated with visual impairment and increased mortality in children, particularly from measles and diarrhoea. Treatment with vitamin A has been shown to reduce mortality in children with measles infection.[1, 2] Vitamin A used as primary prevention has been shown to reduce all-cause mortality in babies aged < 6 months,[3, 4] and in infants > 6 months of age.[5]

• Infants < 6 months: 50,000 IU at 6, 10 and 14 weeks
• Infants 6 - 12 months: 100,000 IU every 4 - 6 months
• Children > 12 months of age: 200,000 IU every 4 - 6 months
• Post-partum women: 200,000 IU x 2 doses within 6 weeks of delivery, at least 24 hours apart
• Additional guidelines are available for treatment of xerophthalmia.

Note: *High risk is defined as: measles, diarrhoea, respiratory disease, chicken pox, severe protein calorie malnutrition or living in vicinity of children with clinical Vitamin A deficiency.

Prevalence of vitamin A deficiency

Low vitamin A was found in 19% - 38% of African refugee children attending RCH immigrant health clinic in the early 2000s (noting many of these children had spent time in refugee camps) [8,9] and 3% of Karen refugee children in a community based sample in Victoria.[10] No cases of xerophthalmia have ever been identified within our service.

Assessment

• Consider vitamin A deficiency in children from Africa and South Asia , especially if they have had restricted food access pre-arrival, or have poor nutrition. Maps of prevalence are available.
• Eye signs of vitamin A deficiency: night blindness, Bitot's spots (grey-white deposits on the bulbar conjunctiva adjacent to the cornea) or xerophthalmia (dryness, corneal ulceration, keratomalacia).
  • Children with eye signs should be referred for urgent ophthalmology assessment .

Screening

• Screening for low Vitamin A is part of the initial refugee health assessment for children where food access has been restricted. Screening is probably unnecessary in children after initial settlement if they have good nutritional status and an age appropriate diet
• The laboratory should report age-specific ranges for serum Vitamin A. A serum retinol < 0.7 micromol/l is significantly low for children of all ages
  • Serum retinol may be transiently low during acute infections
  • Vitamin A is light sensitive and blood samples for testing must be protected from light, otherwise levels will be (falsely) low

Management

• Promote breast feeding of infants and encourage Vitamin A rich foods for infants and children
  • Vitamin A rich foods include yellow fruits and vegetables, butter/margarine, cheese, eggs and offal (liver, kidney)
  • Vitamin A is destroyed by prolonged cooking, and the vitamin A content of foods can be reduced by drying or freezing
• Low vitamin A should be treated (Table 1). High dose capsules (50,000 IU) containing an oil-based solution (and gelatin) are available, these do not require a prescription, although they may need to be ordered in the community setting.

Table 1: Treatment of low vitamin A

Vitamin A level	Age	Vitamin A dose	Follow-up
0.35 - 0.7 micromol/L(or low for age)	< 6 months 6 - 12 months > 12 months	50,000 IU stat 100,000 IU stat 200,000 IU stat	Repeat dose at 6 months if risk factors persist
< 0.35 micromol/L(or eye signs)	< 6 months 6 - 12 months > 12 months	50,000 IU oral daily for 2 days 100,000 IU oral daily for 2 days 200,000 IU daily for 2 days	Follow-up levels and repeat dose at 2 - 4 weeks

• Australian recommended daily intakes [11] are shown below in Table 2.

Toxicity

• Vitamin A toxicity may follow doses of 20 times the RDI in children, although high dose supplementation in children with measles is not associated with acute toxicity/adverse effects.[1]
• Side effects include irritability, vomiting and bulging fontanelle in 1 - 2%, which generally resolves within 48 hours of ingestion.[12]
  
  • Vomiting is more common in those aged < 6 months and is usually mild and self-limited.[6]
  • Massive overdose can cause rough skin, dry hair, hepatomegaly, and raised ESR, serum calcium and ALP.
• High dose Vitamin A should not be given to women of child-bearing age who may be pregnant. Doses should not exceed 10,000 units a day or 25,000 units a week.[13] Most commercial cod-liver oil capsules contain less than this amount.

Table 2. Australian Recommended Dietary Intake Vitamin A by life stage and gender

Infants	Gender	AI
0 - 6 months	All	250 mcg/day of retinol (as retinyl esters)
7 - 12 months		430 mcg/day of retinol equivalents
Children and adolescents	Gender	EAR as RE	RDI as RE
1 - 3 years	All	210 mcg/day	300 mcg/day
4 - 8 years		275 mcg/day	400 mcg/day
9 - 13 years	Girls	420 mcg/day	600 mcg/day
14 - 18 years		485 mcg/day	700 mcg/day
9 - 13 years	Boys	445 mcg/day	600 mcg/day
14 - 18 years		630 mcg/day	900 mcg/day

Note: The Adequate Intake (AI) is used when no EAR or RDI is available and is based on observed/experiemental intakes. The Estimated Average Requirement (EAR) reflects the estimated median requirements, the Recommended Daily Intake (RDI) meets or exceeds the requirements for 97.5% of the population. RE = retinol equivalents.

References

• References

_{Immigrant health resources. Initial: Georgie Paxton and Emma Magrath. Last updated September 2018 Contact: georgia.paxton@rch.org.au}