Vitamin D is a fat-soluble vitamin, which regulates the formation of bone and absorption of calcium from the intestine. It is also necessary for the immune system to fight infections. Vitamin D deficiency leads to the development of soft, brittle and misshapen bones (rickets) in children. Suboptimal Vitamin D status is seen in 7% of toddlers and 10-16% in teenagers and there is growing public health concern around Vitamin D status in general. Deficiency is preventable in infants and toddlers and all vulnerable groups should supplement with 10ug Vitamin D daily throughout winter months.
Vulnerable to vitamin D deficiency
Infants and toddlers are vulnerable to Vitamin D deficiency if their mother was Vitamin D deficient during pregnancy, either low exposure to sunlight or not taking a supplement. Children with pigmented skin in particular those from Asia, Africa and the Middle East are at greater risk of deficiency that white children. Breast milk is low in Vitamin D, and lower still if the mother was deficient during pregnancy. Public Health England (PHE) and the SACN (Scientific Advisory Committee on Nutrition) recommend that all vulnerable groups should take a Vitamin D supplement of 10 micrograms (ug) daily (400 international units) for around 6 months of the year, and preferably throughout the winter months. Vulnerable groups include:
- pregnant and breast feeding mothers
- all infants under one year of age
- all children until 4 years of age
The Sunshine Vitamin
About 90% of our requirements for Vitamin D come from action of the sunlight on the skin. The sun’s UV rays cause Vitamin D to be formed on the skin. This is then absorbed into the blood stream, which can either be stored for future needs or passed through the liver and kidneys to become actively used by the body. The body’s ability to store Vitamin D is important as it is only made during the summer months. 20 minutes of UV sunlight (10am – 3pm) from April to October on face, arms and legs daily is sufficient to provide adequate Vitamin D all year round. The use of sun block and sunscreens reduce Vitamin D production. Do use sunscreens when you are exposed to strong sunshine for extended periods eg. on the beach or during outdoor sports. Short periods in the sunshine without sunscreen give sufficient sun exposure to produce Vitamin D.
Dietary Vitamin D
The remaining 10% of our Vitamin D is supplied by dietary intake. Good dietary sources are limited and the best and only significant source is oily fish. Smaller amounts can be found in eggs and fortified foods like infant formula, margarine and breakfast cereals. Diet alone cannot supply sufficient vitamin D without exposure to sunlight.
For further information the latest evidence for Vitamin D and Health, see link to post on is the sunshine vitamin enough?