Vitamin D is a nutrient that is vital for the development of healthy bones.

Vitamin D serves several important functions in relation to calcium metabolism. It helps to increase calcium absorption from the gastrointestinal system and kidney and thereby make it available to body tissues and the blood. It also functions to aide with the deposition of calcium to bone.

The body’s main source of vitamin D arises from the manufacture of this vitamin in the skin on exposure to sunlight. Research has found many people are deficient in vitamin D due to more time being spent indoors. Only 10 – 15 minutes of exposure to outdoor sun is necessary for the production of vitamin D. However, it is important to avoid excessive exposure from sunlight, particularly in Summer due to the risk of skin damage and skin cancers.

Dietary sources of vitamin D are limited. These sources of vitamin D from the diet arise often from foods fortified (boosted) with vitamin D such as milk, soy drinks, margarine and cereals. It is also found naturally in liver, fish (tuna, salmon, sardines, herring and mackerel) and egg yolk.⁶

Certain individuals with limited exposure to sunlight are at risk of vitamin D deficiency. The institutionalised,⁷ housebound elderly,⁸ veiled women and dark skin individuals may be at risk of vitamin D deficiency,⁹ Also individuals with illnesses of the gastrointestinal system such as Coeliac disease¹⁰ may not absorb adequate amounts of vitamin D from the diet. In high-risk individuals such as the elderly or those found to have low levels of vitamin D, vitamin D supplements are appropriate.^11,12 In addition, if calcium intake from dietary sources is inadequate, the use of calcium supplements may be necessary.

You should discuss with your doctor whether you require supplements of calcium or vitamin D.

Content updated February 20, 2006