Micronutrients: Vitamin D

Micronutrients: Vitamin D

Last week we talked about vitamin A, this week we will look at another of the fat-soluble vitamins, vitamin D.


Vitamin D, sometimes known as ‘The Sunshine Vitamin’ has several important functions in the body. Vitamin D - More than just strong bones caption with picture of skeleton handIt’s most well known function is related to calcium absorption. Adequate calcium intake is essential for healthy teeth and bones. Even with a diet that is rich in calcium, without sufficient levels of vitamin D, the body is unable to absorb the calcium.

A lack of vitamin D and subsequent calcium malabsorption can lead to bone deformities such as rickets in children and bone pain and tenderness as a result of a condition called osteomalacia in adults. There is accumulating evidence that vitamin D may also play a role in the prevention of serious chronic diseases including cardiovascular disease, diabetes mellitus, some inflammatory and autoimmune disorders as well as some types of cancers such as colorectal cancer in men and breast cancer in women.


Due to Irelands northerly latitude, little to no vitamin D can be produced from sunlight during the Vitamin D Sourceswinter months (October to March) as very little UVB light from the sun reaches the surface. This lack of vitamin D production from the sun increases reliance on dietary intakes of vitamin D to ensure sufficient status. However dietary sources are limited:

  • Oily fish such as salmon, sardines and mackerel
  • Eggs
  • Fortified foods such as cereals and milks


Groups at risk of not getting enough vitamin D are:

  • All pregnant and breastfeeding women
  • Babies and children under the age of 5
  • Older people aged 65 years and over
  • People with darker skin tones such as those of African, African-Caribbean and South Asian origin
  • Anyone who spends very little time outside during the summer such as the housebound, office workers, shift workers


Approximately 10 – 15 minutes of sunlight per day (depending on skin type and sunscreen usage) Sun shining through treesduring the summer months will enable the body to produce sufficient vitamin D. But it is also important to avoid over exposure due to the increased risks of skin cancer.

The HSE recommends that to ensure all babies get enough vitamin D they should be given 5 micrograms (200 IU) every day from birth to 12 months whether breastfed, formula fed or taking solid foods.

The British Dietetic Association recommends that people should take a daily supplement containing 10 micrograms (400 International Units) of vitamin D if they are aged 65 or over or have limited sunlight exposure.

All pregnant and breastfeeding women should take a daily supplement of 10 micrograms (400IU) of vitamin D to ensure the mothers requirements are met and to build adequate foetal stores for early infancy.

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Liam Leech, BSc (Hons) Sport and Exercise Science, MSc. ANutr.

Liam Leech

BSc (Hons) Sport and Exercise Science, MSc. ANutr.





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