In summer months, the majority of the population will get enough vitamin D through exposure to sunlight and a healthy, balanced diet.
Between October and early March the NHS says we do not make enough vitamin D from sunlight, so you need to get vitamin D from your diet.
Dietary vitamin D is available in foods such as oily fish, cod liver oil, red meat, fortified cereals, fortified spreads and egg yolks.
In the UK, milk is not fortified with vitamin D, so dairy products contain only small amounts of vitamin D.