Insufficient in Ireland is also set at 30--50 nmol/L (12--20 ng/mL).

Sunlight UVB radiation needed to make vitamin D is only available in Ireland during the months of April through October. This is due to our geographic location 52o - 55o North and means that Ireland experiences a ‘vitamin D winter’ that stretches from the end of October to late March.

Currently, 94 % of children, 94 % of teenagers and 90 % of adults on the island of Ireland have inadequate vitamin D intakes. Therefore, almost everybody in Ireland needs a supplement of vitamin D and 15 µg (600 IU) is recommended on a daily basis.

N.B. In the early 2000s, over 20 cases of rickets (a weakening of the bones caused by severe vitamin D deficiency) in infants and toddlers were reported in Ireland.