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Vitamin D deficiency is common in Ireland


Vitamin D is vital for good health, growth and strong bones. A lack of this important vitamin is common, particularly in Ireland, as it is made in the skin by exposure to the sun - something we don't have a lot of here!

Vitamin D is a fat soluble vitamin which means that it can be stored in our body for future use. The main action of vitamin D is to help absorption of dietary calcium and phosphorus, which is essential for bone structure and strength. Vitamin D is made in our skin following exposure to sunlight. The required sunlight has to fall on bare skin for 20 to 30 minutes. Two to three exposures of sunlight per week from April to September is enough to achieve healthy amounts of the vitamin in our bodies. Foods containing vitamin D include oily fish, egg yolk and fortified foods, such as certain margarines, cereals and infant formula.

Vitamin D deficiency

People at most risk of being deficient in Vitamin D include the following

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  • Pregnant or breast feeding women, especially women who have had several babies within a short time frame may suffer from vitamin D deficiency. This is because extra vitamin D is required for growth.
  • Breast fed babies whose mothers lack vitamin D or babies who are fed for prolonged periods of time are also at risk.
  • People who have very little sunlight exposure will also require supplementation. In particular:
  • Housebound patients.
  • People who cover up when they go outside.
  • People with dark skin.
  • Strict sunscreen users.
  • Elderly people have thinner skin which is less capable of making vitamin D and are a particularly vulnerable group.
  • Patients with Crohn's disease, coeliac disease and some types of liver and kidney diseases are also at risk of vitamin D deficiency.
  • Strict vegetarians, vegans or those who do not eat fish certainly require supplementation.


Symptoms are often nonspecific or vague:

  • Babies with severe vitamin D deficiency can have muscle cramps, seizures and breathing difficulties. They may be irritable, more prone to infections, have delayed teething and may be reluctant to start walking.
  • Children with severe deficiency may have soft skull or leg bones and their legs may look curved.
  • Adults with vitamin D deficiency tend to complain of vague aches and pains. In severe cases, they may complain of difficulty standing up or climbing stairs, and may walk with a waddling pattern. Bone pains may develop in the ribs, hips, pelvis, thighs and feet.


A diagnosis of vitamin D deficiency is based on thorough medical history including patient symptoms and examination. A simple blood test will be performed and this will then confirm the diagnosis.


The treatment of vitamin D deficiency supplementation with a form of vitamin D called ergocalciferol or calciferol. These products need to be taken daily for 12 months in order to allow the body to catch up on reduced levels. After the deficiency has been treated, the body's stores of vitamin D need to be maintained with further supplementation. Those treated for vitamin D deficiency will need to be reviewed a few weeks or months after starting treatment. A further review after one year is advised.


As mentioned, various groups of people are prone to developing vitamin D deficiency and are therefore advised to take vitamin D supplements. This includes:

  • Pregnant and breast feeding women.
  • Breast fed babies.
  • Young children up to the age of five years.
  • All people aged 65 years and over.
  • Individuals whose skin is not exposed to sun.
  • Those who have dark skin.
  • People who suffer with certain intestinal, kidney or liver diseases.