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CPD Module 1: Vitamin D status of young children

The importance of vitamin D has come to the fore in recent years leading to frequent discussion...

Supported by Petit Filous

This module will:

  • Introduce vitamin D: what it does in the body, where we find it in the diet and the consequences of vitamin D deficiency for children’ health.
  • Describe the latest advice on vitamin D from Public Health England (PHE).
  • Provide figures on vitamin D intakes and prevalence of deficiency in UK children using the National Diet and Nutrition Survey (NDNS), a government rolling survey of the UK population.
  • Offer practical advice to identify children who may be at risk of vitamin D deficiency, and suggest ways to improve children’s vitamin D status[1].
     

What is vitamin D and why is it essential?

Often called ‘the sunshine vitamin’, vitamin D is a hormone which our bodies make in response to sunlight. However, as a particular wavelength of light is needed for vitamin D synthesis, we only get the right spectrum of sunlight during April to September. From October to March, body stores of vitamin D must be topped up from the diet to maintain an optimal vitamin D status.

Vitamin D is vital for normal development of bones, teeth and muscles, and is proven to support normal immune function[2][3]. These functions are particularly important in children as they are growing and developing. Emerging research suggests that vitamin D may have other roles, e.g. heart health, prevention of auto-immune diseases, prevention of type 2 diabetes[4] and treatment of asthma[5].

Vitamin D deficiency can cause seizures and cardiomyopathy in infants, rickets and poor growth in children and muscle weakness at any age.  

Signs and symptoms include aches and pains; myopathy causing delayed walking and rickets with bowed legs, knock knees, poor growth and muscle weakness[6].

Sources of vitamin D

Regular sun exposure in the summer provides around 90% of our vitamin D. The remaining 10%, plus all of our vitamin D in winter, is made up from the diet[7].

Oily fish, such as salmon, mackerel, sardines, herring, tuna and trout, is the best natural source of vitamin D[1][8]. However, just one in five children in the UK eats oily fish regularly[9]. Alternative dietary sources include egg yolk, fortified dairy products such as fromage frais and yogurt, fortified breakfast cereals, and meat (which is not a rich source but nevertheless provides around 23% in the diet due to the amounts consumed). Current EU regulations do not allow baby foods to be fortified with vitamin D.

The NDNS (years 1-4)[10] reveals the main dietary contributors to vitamin D intakes in UK children aged 1½ to 3 years and 4 to 10 years (see Figure 1). Interestingly, in the latest NDNS (years 5-6)[11], yogurt and fromage frais and other dairy desserts provided 15% of vitamin D in younger children and 7% in older children highlighting the importance of these dairy foods.

Figure 1: Dietary contributors to vitamin D intake in UK children [10]

 

New vitamin D recommendations

In 2016, the Scientific Advisory Committee on Nutrition (SACN) produced a report which recommended that everyone over the age of four years should aim to consume 10 micrograms of vitamin D daily. The full recommendations are given in Table 1.

Table 1: SACN guidance on vitamin D

 

SACN clearly stated that “it is difficult to achieve the RNI/Safe Intake from natural food sources alone” and recommended that the Government consider strategies to boost vitamin D intakes. Therefore, PHE came out with a strong public health message to combine natural sources with fortified foods and dietary supplements[12]

Is vitamin D in young children an issue in the UK?

Yes, the NDNS[11] shows that a fifth of the general population is deficient in vitamin D – defined as having a blood level of hydroxyvitamin D below 25 nanomoles per litre – and there has been a resurgence of rickets in some communities.Figure 2 presents the proportion of children with vitamin D deficiency which increases with age, probably because fortified milk consumption declines without being replaced by other rich sources of vitamin D.

Figure 2: Proportion of UK children with vitamin D deficiency[1][14]

 

However, it is difficult to get all the vitamin D we need from the diet due to limited natural sources, so intakes are low across most age groups. Toddlers consume just 3.9 micrograms daily on average, falling to 2.0 micrograms in 1½ to 3 year olds and 2.4 micrograms in 4 to 10 year olds[10].

As sunshine provides 90% of vitamin D in the summer, children with limited sun exposure rely more heavily on dietary sources. Concern about skin cancer has led to strict policies on sun protection in nurseries and schools. As these all block sunlight, an unintended consequence has been reduced vitamin D synthesis and increased vitamin D deficiency amongst children.

Practical considerations for improving vitamin D status

Health visitors and other Community Practitioners can have a positive impact on vitamin D status in families with babies and young children by identifying those who are at risk, and by delivering appropriate advice on sun exposure, diet and supplementation. The box below suggests how these groups may be identified.

Identifying children at risk of poor vitamin D status

  • Those living in Northern parts of the UK.
  • Children who cover their skins for cultural or religious reasons.
  • Children using sunblock in summer.
  • Children whose mothers were low in vitamin D during pregnancy.
  • Vegetarian or vegan children.
  • Children with darker skins.
  • Obese children.
  • Children from lower socio-economic groups.
  • There is much confusion about how much sun exposure is needed to ensure adequate vitamin D status. A NICE guideline[15] outlined the benefits and risks of sun exposure but advised people to manage their own risks as the likelihood of burning will differ depending on the season, time of day and skin tone.

However, an expert group[16] claimed that exposure of the arms and face between 11am and 3pm for 10-15 minutes daily would probably be enough for most light skinned people. Sun bathing is not required. After this time, normal precautions to avoid sun burn should be taken, particularly for children. People with darker skins may need longer in the sun but care should still be taken to avoid sunburn.

Diet plays a vital role, especially in winter, and children should be offered a variety of vitamin D sources which will include oily fish, eggs, fortified dairy products such as Petits Filous fromage frais and yogurt, fortified breakfast cereals, fortified milks, as well as supplements in line with NHS advice[17].

Summary of practical advice

  • Children should be encouraged to play outside between 11am and 3pm during April to September for 10-15 minutes before sun cream and other precautions to avoid sunburn are applied. Individual risk of burning should be carefully assessed and time in the sun moderated accordingly.
  • Children’s diets should include vitamin D-rich foods such as fortified dairy products (daily), eggs (several times weekly) and oily fish (once a week).
  • Children aged one to four years, and anyone with darker skin, should take a daily supplement of vitamin D as per NHS guidance.
  • In addition, everyone aged over four years should take a 10 microgram supplement daily from October to March.

Conclusions

Vitamin D deficiency is a major issue in the UK leading to a greater risk of poor bone health. Current mean intakes in children are in the region of 2.0 to 2.4 micrograms daily[10], well below the recommended 10 micrograms. Advice on safe sun exposure and consumption of foods rich in vitamin D should be given to all at risk groups. Supplements are warranted in winter and spring.

  • Dr Carrie Ruxton, registered dietitian

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References

  1. Scientific Advisory Committee on Nutrition (2016). Vitamin D and health. www.gov.uk/government/publications/sacn-vitamin-d-and-health-report
  2. European Commission (2012) Commission Regulation (EU) No 432/2012 establishing a list of permitted health claims made on foods, other than those referring to the reduction of disease risk and to children’s development and health. Official Journal of the European Union L136: 1–40.
  3. European Commission (2016) EU Register of nutrition and health claims made on foods. http://ec.europa.eu/food/safety/labelling_nutrition/claims/register/public/?event=register.home
  4. Lapp JL (2009 Vitamin D: Bone health and beyond. American Journal of Lifestyle Medicine 3: 386-393.
  5. Cochrane Reviews (2016) http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD011511.pub2/abstract
  6. Royal National Orthopaedic Hospital. www.rnoh.nhs.uk/clinical-services/paediatric-adolescents/vitamin-d-children
  7. Ruxton CHS, Derbyshire E (2009). Health impacts of vitamin D: are we getting enough? Nutrition Bulletin 34: 185–197.
  8. National Institutes for Health website https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/
  9. Ruxton CHS (2011). The benefits of fish consumption. Nutrition Bulletin 36: 6-19.
  10. Bates et al. (2014) National Diet and Nutrition Survey. Results from years 1 to 4 (combined) of the Rolling Programme. London: PHE/FSA.
  11. Bates et al. (2016) National Diet and Nutrition Survey. Results from years 5 and 6 (combined) of the Rolling Programme. London: PHE/FSA.
  12. Public Health England (2016) PHE publishes new advice on vitamin D. www.gov.uk/government/news/phe-publishes-new-advice-on-vitamin-d
  13. Pearce SHS & Cheetham TD (2010) Diagnosis and management of vitamin D deficiency. British Medical Journal 340: b5664.
  14. NatCen Social Research et al. (2013). Diet and Nutrition Survey of Infants and Young Children, 2011. www.gov.uk/government/publications/diet-and-nutrition-survey-of-infants-and-young-children-2011
  15. NICE (2016) Sunlight exposure: risks and benefits. www.nice.org.uk/guidance/ng34
  16. Cancer Research UK (2010) Joint position statement. www.cancerresearchuk.org/about-us/cancer-news/news-report/2010-12-16-joint-position-statement-issued-to-provide-vitamin-d-clarity?rss=true
  17. NHS Choices (2015) Vitamins and minerals: vitamin D. www.nhs.uk/Conditions/vitamins-minerals/Pages/Vitamin-D.aspx

 

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