To protect bone and muscle health, everyone over one year of age needs 10 micrograms of vitamin D daily, according to a new report issued to the British government on Thursday.

The new recommendation, made by the Science Advisory Committee on Nutrition (SACN), comes after a five-year review which revealed one in five people in Britain has insufficient vitamin D levels.

Vitamin D is essential for the absorption of calcium, which is vital to maintain healthy bones and teeth. The human body makes most of its vitamin D from direct sunlight on the skin but we also get a small amount from some foods, including oily fish and eggs.

Groups most at risk of vitamin D deficiency include people who don't spend a lot of time outdoors, ethnic minority groups with darker skin, which doesn't make vitamin D as easily, and people in occupations with limited sunlight exposure such as night shift workers, the report says.

"Until now it has been assumed that sunlight would provide the vitamin D needed by most of the population all the year round. We now know this is not true because about one in five people in the UK have a low blood level of vitamin D," said Prof. Hilary Powers from the University of Sheffield, who chairs the SACN.

The SACN have recommended that in order to achieve this blood level people in Britain need 10 micrograms of vitamin D daily. However, the average intake of vitamin D from food and supplements is only about three micrograms.

"There are very few foods that contain a good source of vitamin D so it is very important to ensure we include a variety of oily fish, such as tuna, salmon and sardines, eggs and certain fortified breakfast cereals in our diets," said Powers.