The authority's report, Recommendations for a National Policy of Vitamin D Supplementation for Infants in Ireland, comes in response to observations that many of the country's infants, adults, adolescent girls and pregnant women had poor vitamin D status, placing them at risk of health problems later in life. "It is evident that low intakes of vitamin D are prevalent among all age groups throughout Ireland and that the recommended daily intake of 5micrograms of vitamin D per day is not being met," said Dr Mary Flynn, chief specialist in public health nutrition, FSAI. "Babies are most susceptible to developing the bone deformities associated with rickets because of the rapid growth and development that occurs during the first year of life and the likelihood of having insufficient stores of vitamin D to meet their needs. It is therefore necessary to adopt a clear, simple and safe recommendation. We conclude that all infants aged 0-12 months living in Ireland would benefit from vitamin D supplementation," she said. Vitamin D refers to two biologically inactive precursors - D3, also known as cholecalciferol, and D2, also known as ergocalciferol. The former, produced in the skin on exposure to UVB radiation (290 to 320 nm), is said to be more bioactive. The latter is derived from plants and only enters the body via the diet, from consumption of foods such as oily fish, egg yolk and liver. Both D3 and D2 precursors are hydroxylated in the liver and kidneys to form 25- hydroxyvitamin D (25(OH)D), the non-active 'storage' form, and 1,25-dihydroxyvitamin D (1,25(OH)2D), the biologically active form that is tightly controlled by the body. However, Ireland's northerly latitude means that vitamin D production from sunlight is severely compromised particularly during the winter months of October to March. The report also highlights that the dietary sources of the vitamin - including fortified foods - were not able to raise vitamin D levels in the Irish population. According to the FSAI's report, as many as 23 cases of rickets were reported in recent years at two Dublin-based paediatric hospitals. As rickets is the most extreme consequence of vitamin D deficiency, the FSAI expects the incidence of deficiency in Ireland is underestimated. But before a policy of supplementing all infants with vitamin D can start in Ireland, a new supplement containing only vitamin D needs to be formulated, said FSAI. The only currently available supplement for infants in Ireland, Abidec, also contains vitamin A, which when combined with infant formula, exceeds the safe upper limit of vitamin A. Once available, this new vitamin D supplement should be accessible to all infants aged 0-12 months, said the authority. Interest in vitamin D has been increasing around the world for all age groups, with calls to increase vitamin D intake growing louder. Indeed, only recently fifteen experts from universities, research institutes, and university hospitals around the world called for international agencies to "reassess as a matter of high priority" dietary recommendations for vitamin D because current advice is outdated and puts the public at risk of deficiency (The American Journal of Clinical Nutrition, Vol. 85, pp. 860-868). A recent review of the science reported that the tolerable upper intake level for oral vitamin D3 should be increased five-fold, from the current tolerable upper intake level (UL) in Europe and the US of 2000 International Units (IU), equivalent to 50 micrograms per day, to 10,000 IU (250 micrograms per day).