Estimation of the dietary requirement for vitamin D in healthy adults

Kevin D. Cashman, Tom R. Hill, Alice J. Lucey, Nicola Taylor, Kelly M. Seamans, Siobhan Muldowney, Anthony P. FitzGerald, Albert Flynn, Maria S. Barnes, Geraldine Horigan, Maxine P. Bonham, Emeir Duffy, JJ Strain, Julie Wallace, Mairead Kiely

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208 Citations (Scopus)


Background: Knowledge gaps have contributed to considerable variation among international dietary recommendations for vitamin D. Objective: We aimed to establish the distribution of dietary vitamin D required to maintain serum 25-hydroxyvitamin D [25(OH) D] concentrations above several proposed cutoffs (ie, 25, 37.5, 50, and 80 nmol/L) during wintertime after adjustment for the effect of summer sunshine exposure and diet. Design: A randomized, placebo-controlled, double-blind 22-wk intervention study was conducted in men and women aged 20-40 y (n = 238) by using different supplemental doses (0, 5, 10, and 15 mu g/d) of vitamin D 3 throughout the winter. Serum 25(OH) D concentrations were measured by using enzyme-linked immunoassay at baseline (October 2006) and endpoint (March 2007). Results: There were clear dose-related increments (P < 0.0001) in serum 25(OH) D with increasing supplemental vitamin D-3. The slope of the relation between vitamin D intake and serum 25(OH) D was 1.96 g(-1) intake. The vitamin D intake that maintained serum 25(OH) D concentrations of >25 nmol/L in 97.5% of the sample was 8.7 mu g/d. This intake ranged from 7.2 mu g/d in those who enjoyed sunshine exposure, 8.8 mu g/d in those who sometimes had sun exposure, and 12.3 mu g/d in those who avoided sunshine. Vitamin D intakes required to maintain serum 25(OH) D concentrations of >37.5, >50, and >80 nmol/L in 97.5% of the sample were 19.9, 28.0, and 41.1 mu g/d, respectively. Conclusion: The range of vitamin D intakes required to ensure maintenance of wintertime vitamin D status [as defined by incremental cutoffs of serum 25(OH) D] in the vast majority (>97.5%) of 20-40-y-old adults, considering a variety of sun exposure preferences, is between 7.2 and 41.1 mu g/d. Am J Clin Nutr 2008; 88: 1535-42.
Original languageEnglish
Pages (from-to)1535-1542
JournalAmerican Journal of Clinical Nutrition
Issue number6
Publication statusPublished (in print/issue) - Dec 2008


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