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Vitamin deficiency in children: cause for concern?


 - Overt vitamin deficiency is uncommon in children in the UK (apart from vitamin D).


 - Those who cover up their skin, have high skin pigmentation or who spend little time outdoors risk low levels of vitamin D


 - The Department of Health recommends that children over six months and under five years are given a daily supplement of vitamins A, C and D

As a dietitian I have regularly reviewed a child's meagre nutritional intake and been asked by the parent whether the child is at risk of vitamin deficiency. Many parents report that their children's diets are limited by variety, portion size or both. But just how prevalent is vitamin deficiency in children in the UK? What vitamins pose the biggest concern? Which children are most at risk of deficiency? And should children be given vitamin supplements routinely?

How common is vitamin deficiency in 
children in the UK?

For the majority of children most vitamins are relatively easy to obtain through a mixed and varied diet by including foods daily from the five food groups. Children with acute or chronic disease may have different requirements.

Parents and healthcare professionals often have concerns if the children have limited intakes of fruit and vegetables. Recent evidence suggests that fruit and vegetable intake in school children was less than desired, especially in 15-18 year olds (200g per day as opposed to the suggested 400g per day). A fifth of children surveyed aged four to 18 years ate no fruit during the study period, with 4% eating no vegetables.1 With limited fruit and vegetable intake, adequate levels of vitamins A and C may be at risk.

Vitamin A is involved in immune function, healthy skin, night vision and growth. Sources of vitamin A are shown in Table 1. Vitamin C has a role in immunity and maintaining good health, but also importantly in facilitating the absorption of iron, especially from non-haem (vegetarian) sources. Sources of vitamin C are shown in Table 2. For these and most other vitamins however, overt deficiency is rare. Intakes of key vitamins from all dietary sources were above or close to recommendations for all age groups with the exception of vitamin D, according to the National Diet and Nutrition Survey (NDNS) in 2011.2 The results presented from this survey did not specifically address children who were fussy eaters.

Vitamin D is the vitamin we need to be the most concerned about. Mean vitamin D intakes were lower than in previous NDNS surveys.3 There has also been a rise in vitamin D deficiency in the UK in recent years. Vitamin D deficiency can cause a variety of different symptoms including muscle spasms, poor growth, poor dental development, irritability, immune problems and ultimately rickets where the child develops bone deformity and may have curved or bowed legs. With better nutrition in the post-war years it was felt to be a disease of the past, but a study in 2011 showed that 32% of children attending a paediatric orthopaedics unit had vitamin D levels below 50nmol/l, and were at risk of deficiency.4

Who is at risk of vitamin D deficiency?

Those who cover up their skin, have high skin pigmentation or who spend little time outdoors risk low levels of vitamin D are most at risk of being deficient in vitamin D. This is because the major contributor to vitamin D status is not from diet (oily fish and fortified foods provide only small amounts), but from the action of sunlight on skin. A study from 2011 found 35% of 4-18 year olds had low vitamin D levels. Levels were not affected by diet or gender but there was an increased risk of low levels in non-white skin types, those who exercised outdoors less, who watched more TV and who were overweight.5 In the UK, sunlight is only effective at making vitamin D under the skin from April to September. With safe sun messages to cover up and put on high sun protection factor cream, it has been easy to forget about the invaluable contribution sunshine makes to healthy vitamin D levels. Sun cream can prevent vitamin D production. Parents need to be given sensible advice about safe sun exposure for themselves and their children enabling them to avoid the damaging effects of the sun, while maximising their vitamin D absorption.

The National Institute for Health and Care Excellence (NICE) in association with Cancer Research UK have stated that “Sun exposure is the most important source of vitamin D. The many factors that affect vitamin D production make it impractical to offer a one-size-fits-all sun exposure recommendation, but the time required to make sufficient amounts is typically short and suberythemal (before the point of sunburn). Regularly going outside for a matter of minutes around the middle of the day without sunscreen, while taking care to avoid sunburn, should be enough to provide the benefits of vitamin D without unduly raising the risk of skin cancer.”6

There are other vulnerable groups at risk of vitamin D deficiency. The Department of Health (DH) recommends that a daily dose of vitamins A (233ug), C (20mg) and D (7.5ug) be taken by the following groups:7
    
  - Breastfed infants from six months (or from one month if there is any doubt about the mother's vitamin status during pregnancy).

 - Infant formula-fed infants who are over six months and taking less than 500ml infant formula milk per day.

 - Children under five years of age.

The vitamins are available as part of the Healthy Start scheme up until the age of four, or can be bought widely in pharmacies and supermarkets. Parents are encouraged to give them to their children because of the sometimes erratic nature of childhood eating and the relatively high requirements of young children. Pregnant and breastfeeding women are advised to have a daily supplement of vitamins C, D and folic acid. Despite the recommendations, a study in 2011 highlighted a lack of knowledge about vitamin supplementation guidelines. Only 52% of midwives and health visitors were aware of DH guidelines.8 This contrasted with a 2006 study in which 81% of health visitors recommended vitamins for breastfed infants at six months and 57% recommended vitamins until five years. Eight out of ten health visitors successfully identified Asian children as being particularly at risk of vitamin D deficiency, but were much less likely to identify Black Africans (29% of health visitors) and Black Caribbeans (16% of health visitors) as also being at risk.9

What about fussy eaters?

Fussy eating is extremely common in toddlers and food refusal is quite normal, especially with new foods. Parents often worry about vitamin deficiencies and may need support during this temporary situation. They should be encouraged, where possible, to include foods from each of the main food groups daily. Small amounts of new foods tried often are the most likely to work. Parents should avoid force-feeding or offering food as a reward, and aim to eat at least some meals with their child to set a good example of eating. Parents should offer vitamins A, C and D up until the age of five. Enlarging the diet through increasing the variety of food, rather than relying on vitamin supplements, should be the aim; but continuing a vitamin supplement may be beneficial if the diet continues to be very limited. Children with extreme food refusal who exist on only a handful of foods will probably need a multivitamin. They will also require input from a multidisciplinary team including paediatrician, dietitian, clinical psychologist and speech and language therapist for a full feeding assessment.

Conclusion

Vitamin deficiency is not prevalent in the UK, apart from a rise in low levels of vitamin D. Most children over five years, eating a varied and mixed diet do not need a daily vitamin supplement. However, recognising the erratic nature of eating in young children and their high requirements, the DH recommends that infants over six months and under five years should have a vitamin A, C and D supplement. Children who limit their intake because of fussy eating may benefit from a vitamin supplement if their intakes are very limited. Evidence suggests that children who are particularly at risk of vitamin D deficiency because of limited sun exposure should take a vitamin D supplement.

References

1.     Ruxton CHS, Derbyshire E. Diet Adequacy in UK School Children. Nutrition & Food Science 2011;41:20-33.
 

2.     DH. Diet and Nutrition Survey of Infants and Young Children. 2011.
 

3.     DH. National Diet and Nutrition Survey. 2008-2010.
 

4.     Davies JH, Reed JM, Blake E, Priesemann M, Jackson AA, Clarke NM. Epidemiology of vitamin D deficiency in children presenting to a pediatric orthopaedic service in the UK. J Pediatr Orthop. 2011;31:798-802.
 

5.     Absoud M, Cummins C, Lim MJ, Wassmer E, Shaw N. Prevalence and predictors of vitamin D insufficiency in children: a Great Britain population based study. 2011.
 

6.     NICE and Cancer Research UK. Vitamin D expert review. 2010. Available at: www.nice.org.uk/nicemedia/live/11871/49665/49665.pdf
 

7.     Scientific Advisory Committee on Nutrition (SACN) Update on vitamin D. Position Statement by the Scientific Advisory Committee on Nutrition. London: The Stationary Office; 2007
 

8.     Locyer V, Porcellato L, Gee I. Vitamin D deficiency and supplementation: are we failing to prevent the preventable? Community Pract 2011;84:23-6.
 

9.     Cleghorn S. Do health visitors advise mothers about vitamin supplementation for their infants in line with government recommendations to help prevent rickets? J Hum Nutr Diet 2006;19:203-8.

Resources
Healthy Start
Infant and Toddler Forum
Vitamin D deficiency leaflet