colecalciferol

Certain people may be at greater risk of vitamin D insufficiency or deficiency. Patients who have low / no exposure to sunlight.²

Vitamin D is synthesised in the skin upon exposure to sunlight containing sufficient ultraviolet B (UVB) radiation and this is the main source for most people.²

Patients with dark skin tones.²

The pigment melanin, which gives skin its brown or black colour, absorbs UV radiation.²

Patients who are over 65.³

The metabolism of vitamin D and calcium becomes more complex with age. Older people have less 7-dehydrocholesterol, which reduces their capacity to produce vitamin D.³

Patients who are overweight.³

Vitamin D is stored in fat cells, but this source is not readily available as it cannot be released until the fat cells are broken down.³

Patients who are vegetarian or vegan.⁴

A study found that, in the UK, plasma 25(OH)D concentrations were lower in vegetarians and vegans than in meat and fish eaters.⁴