• Vitamin D nutrient intake for all life stages.

      McKenna, M; McCarthy, R; Kilbane, M; Molloy, E (Irish medical journal, 2011-04)
      Vitamin D, unlike other nutrients, is a conditionally required nutrient being obtained from two sources – predominantly by skin production upon exposure to natural ultraviolet (UV) solar radiation, and to a lesser extent by oral intake. Being a fat soluble vitamin it has a long half-life of about two weeks and is stored in fat tissues.1 For nearly six months of the year from October to March in Ireland, skin production is absent and the population is dependent on oral intake from natural foodstuffs, (which are consumed in small quantities only), fortified foodstuffs (most notably some milk products for the past 25 years) and vitamin D supplements, either in multivitamin tablets or in combination with calcium tablets.
    • Vitamin D nutritional status in preterm infants and response to supplementation.

      McCarthy, Roberta A; McKenna, Malachi J; Oyefeso, Oyinkansola; Uduma, Ogenna; Murray, Barbara F; Brady, Jennifer J; Kilbane, Mark T; Murphy, John F; Twomey, Anne; O' Donnell, Colm P; et al. (2013-07-14)
      Little is known about vitamin D status in preterm infants and their response to supplementation. To investigate this, we assessed serum 25-hydroxyvitamin D (25OHD) levels using RIA in a consecutive sample of stable preterm very low birth weight (VLBW) infants (born ≤ 32 weeks gestation or birth weight ≤ 1·5 kg), and we explored associated factors. Serum 25OHD level was first assessed once infants were tolerating feeds (n 274). If this first 25OHD level was below 50 nmol/l (20 ng/ml), which is the level associated with covering requirements in terms of skeletal health in the majority, then we recommended prolonged augmented vitamin D intake ( ≥ 10 μg (400 IU) daily) from a combination of fortified feeds and vitamin supplements and follow-up re-assessment at approximately 6 weeks corrected age (n 148). The first assessment, conducted at a median for chronological age of 18 (interquartile range (IQR) 11-28) d, found that 78 % had serum 25OHD levels below 50 nmol/l. Multivariable analysis demonstrated that the determinants of serum 25OHD levels were duration of vitamin D supplementation and gestational age at birth (r 2 0·215; P< 0·001). At follow-up, after a median of 104 (IQR 78-127) d, 87 % achieved levels ≥ 50 nmol/l and 8 % had levels >125 nmol/l, a level associated with potential risk of harm. We conclude that low 25OHD levels are an issue for preterm VLBW infants, warranting early nutritional intervention. In infants with serum 25OHD levels < 50 nmol/l, a vitamin D intake of ≥ 10 μg (400 IU) daily achieves target levels in the majority; however, further work is needed to determine the exact dose to safely meet target levels without overcorrection.