It uses the vitamin to regulate the amount of calcium and phosphate in the body.
Without enough vitamin D, it can lead to severe bone deformities, rickets or osteomalacia.
But you could lower your risk of a vitamin D deficiency by adding certain foods to your diet.
Regularly eating oily fish could help you to obtain the recommended amount of vitamin D, said charity Heart UK.
Oily fish includes herring, mackerel, salmon and sardines, it said.
Liver and fish oil are also good sources of vitamin D, as well as infant formula.
“Vitamin D is a fat-soluble vitamin that is present in only a few foods in our diet,” said the charity.
“It is needed for healthy bones and teeth and to help control how calcium and phosphorus are used in the body.
“Most people find it difficult to get the recommended intake of vitamin D from foods alone.”
You could also top up on vitamin D by eating some breakfast cereals, added Heart UK.
Adding full-fat milk or yoghurt to your cereal could boost the amount of vitamin D in your breakfast even further.
Eggs, meat and fortified spreads are also modest sources of the – so called – ‘sunshine’ vitamin.
Everyone needs about 10mcg of vitamin D every day. That’s the average amount needed to maintain healthy levels in the blood.
But, the average intake of vitamin D from diet is about 2-3mcg a day.
You could top up on vitamin D by spending more time in direct sunlight, said the NHS.
But, some people could be at risk of a vitamin D deficiency during the winter months due to reduced daylight hours.
The Department of Health recommends that everyone takes a 10mcg vitamin D supplement during the winter months.
Some supplements are declared as International Units (IU). 10mcg is the equivalent to 400IU.
Those most at risk of a deficiency are infants, older people, and those that spend most of their time indoors.