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Almost a fifth of UK adults and up to a third of children aged 4 to 10 years have low vitamin levels.  There is now a call for HCPs to encourage the use of daily supplements to prevent vitamin D deficiency among at-risk people including those aged 6 months - 5 years, pregnant and breastfeeding women.



After studying this module you should:

  • Appreciate the sources of vitamin D and the way the body controls vitamin D levels
  • Be able to describe the importance of vitamin D and the interrelationship with other micronutrients during pregnancy and lactation
  • Appreciate the potential consequences of vitamin D deficiency for the mother and her baby
  • Understand the role of licensed daily supplementation in addition to a healthy balanced diet to ensure adequate levels of vitamin D during pregnancy and lactation and into early childhood


  • Read clinical content
  • Complete CPD assessment
  • Receive learning log for your records


Reviewed by: Nicky Clark MA, RM, RGN, ADM, Cert.Ed (of Adults), SFHEA






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      Pre-learning reflection

      Please take a moment to answer these pre-learning questions.  Once completed, click 'next step' below to start this module.  These answers will be logged on your CPD certificate which will be emailed to you on completion as evidence of your learning.


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      • There are five forms of vitamin D, of which vitaminsD2 (ergocalciferol) and vitamin D3 (cholecaliferol - see right) are the most important for humans
      • Sunlight is the main source of vitamin D in the UK 
      • Vitamin D is essential for the uptake for calcium and phosphorus from the diet

      Without vitamin D, humans absorb only 10 to 15% of the calcium, and about 60% of the phosphorus, in the diet


      Already studied the clinical review? Go straight to the test here
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      The vitamin D pathway

      • Ultraviolet B penetrates the skin and converts 7-dehydrochloesterol to previtamin D3.  This, in turn, is transformed rapidly into vitamin D3

      • Enzymes in the liver convert vitamin D3 from the skin and diet into 25-hydroxyvitamin D, the main circulating form
        • Measuring 25-hydroxyvitamin D determines a patient's vitamin D status
      • Enzymes in the kidneys metabolise 25-hydroxyvitamin D into the active form, 1,25-dihydroxyvitamin D
        • Levels of parathyroid hormone, calcium and phosphorus tightly control production of 1,25-dihydroxyvitamin D by the kidneys
      • The placenta synthesises 1,25-dihydroxyvitamin D




      vitamin d
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      Prevalence of vitamin D deficiency

      • Approximately one fifth of UK adults have low vitamin D levels:
        • The proportion of adults aged 19-64 years with low vitamin D levels rises from 8% between July and September to 39% from January to March
        • Almost 75% of Asian adults may have low vitamin D status in the winter
        • The proportion of children aged 4 to 10 years with low vitamin D status rises from 2% between July and September to 32% from January to March
      • In Cardiff, half of women from non-European ethnic backgrounds showed low levels of vitamin D at their first antental appointment

      • In a London antenatal population, the following proportions of women were vitamin D deficient:
        • 64% of Middle Eastern women
        • 58% of black women
        • 47% of Asian women
        • 13% of Caucasian women



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      Signs and symptoms of vitamin D deficiency

      Signs and symptoms

      Adapted from: Royal National Orthopaedic Hospital Trust

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      Effects of low maternal vitamin D status

      • Low maternal vitamin D status has been associated with several neonatal adverse outcomes including:
        • Poor foetal and infant skeletal growth
        • Impaired mineralisation of bones and teeth
        • Rickets with fits and stridor
        • Hypocalcaemia and hypocalcaemic seizures
        • Heart disease
        • Impaired growth during the first year
        • Thin, deficient enamel of primary teeth and dental caries




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      Effects of low maternal vitamin D status

      • Low vitamin D status can cause problems in the mother during pregnancy and lactation that include:
        • Muscle and joint pain
        • Poor appetite
        • General apthay and weakness
        • Babies born small for gestational age
        • Increased risk of first caesarean section
        • Increased risk of bacterial vaginosis in pregnant women



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      CMO recommendations

      • Social and healthcare professionals should encourage vitamin D supplementation by at-risk groups:
        • Children aged between six months and five years
        • Pregnant and breastfeeding women
        • People over 65 years of age
        • People with low or no exposure to the sun
        • People with darker skin
      • At-risk groups should take a daily supplement that provides 100% of the reference nutrient intake

      • Children aged 6 months to 5 years should take vitamin drops containing 7-8.5 micrograms of vitamin D per day
      • Infants who are fed infant formula will not need vitamin drops until they are receiving less than 500ml of infant formula a day

      • Breastfed infants may need to receive drops containing vitamin D from one month of age if their mother has not taken vitamin D supplements throughout pregnancy




      Issues with unlicensed supplements

      • A range of vitamin D supplements are available.  Nurses and other prescribers could consider the following when deciding which formulation to use

      • Unlicensed supplements may have variable content
        • Studies have shown 14.3-171% of label content
        • Cases of hypervitaminosis and hypercalcaemia have occurred with the content was approximately 880 times higher than declared on the label
      • Unregulated excipients may be present in unlicensed supplements

      • Licensed medications have dedicated medical information services, which provide information within 24 hours



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      Now that you have reviewed the learning, please complete the following multiple choice questions to test what you've learnt and receive your CPD certificate.
      What is the main biologically active form of vitamin D?
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      What proportion of children aged 4 to 10 years have low vitamin D status from January to March?
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      Low maternal vitamin D status has been associated with which of these neonatal outcomes?
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      What is the CMO’s recommendation for vitamin D levels in drops for children aged 6 months to 5 years?
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      Post-learning reflection

      Please take a moment to answer these post-learning questions.  These answers will be logged alongside your pre-learning responses on your CPD certificate which will be emailed to you on completion as evidence of your learning.


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