In some countries, vitamin D is listed in micrograms, and the relationship is as follows: 2.5 mcg (micrograms) = 100 IU. 5 mcg = 200 IU. 10 mcg = 400 IU. 15 mcg = 600 IU. 20 mcg = 800 IU.

The NHS warns: "A lack of vitamin D can lead to bone deformities such as rickets in children, and bone pain caused by a condition called osteomalacia in adults." Children from the age of one and ...

Children from the age of one and adults need 10 micrograms (mcg) of vitamin D a day, according to the NHS. Babies up to the age of 1 year need 8.5 to 10 micrograms of vitamin D a day. The NHS ...