British Journal of Nutrition

Human and Clinical Nutrition

Effect of adiposity on vitamin D status and the 25-hydroxycholecalciferol response to supplementation in healthy young and older Irish adults

L. Kirsty Forsythea1, M. Barbara E. Livingstonea1, Maria S. Barnesa1, Geraldine Horigana1, Emeir M. McSorleya1, Maxine P. Bonhama2, Pamela J. Mageea1, Tom R. Hilla3, Alice J. Luceya3, Kevin D. Cashmana3, Mairead Kielya3, J. J. Straina1 and Julie M. W. Wallacea1 c1

a1 Northern Ireland Centre for Food and Health, University of Ulster, Coleraine BT52 1SA, UK

a2 Department of Nutrition and Dietetics, Monash University, Clayton, Victoria, Australia

a3 Department of Food and Nutritional Sciences, University College Cork, Cork, Republic of Ireland

Abstract

There is increasing epidemiological evidence linking sub-optimal vitamin D status with overweight and obesity. Although increasing BMI and adiposity have also been negatively associated with the change in vitamin D status following supplementation, results have been equivocal. The aim of this randomised, placebo-controlled study was to investigate the associations between anthropometric measures of adiposity and the wintertime serum 25-hydroxycholecalciferol (25(OH)D) response to 15 μg cholecalciferol per d in healthy young and older Irish adults. A total of 110 young adults (20–40 years) and 102 older adults ( ≥ 64 years) completed the 22-week intervention with >85 % compliance. The change in 25(OH)D from baseline was calculated. Anthropometric measures of adiposity taken at baseline included height, weight and waist circumference (WC), along with skinfold thickness measurements to estimate fat mass (FM). FM was subsequently expressed as FM (kg), FM (%), FM index (FMI (FM kg/height m2)) and as a percentage ratio to fat-free mass (FFM). In older adults, vitamin D status was inversely associated with BMI (kg/m2), WC (cm), FM (kg and %), FMI (kg/m2) and FM:FFM (%) at baseline (r − 0·33, − 0·36, − 0·33, − 0·30, − 0·33 and − 0·27, respectively, all P values < 0·01). BMI in older adults was also negatively associated with the change in 25(OH)D following supplementation (β − 1·27, CI − 2·37, − 0·16, P = 0·026); however, no such associations were apparent in younger adults. Results suggest that adiposity may need to be taken into account when determining an adequate wintertime dietary vitamin D intake for healthy older adults residing at higher latitudes.

(Received August 18 2010)

(Revised April 07 2011)

(Accepted April 14 2011)

(Online publication June 28 2011)

Correspondence:

c1 Corresponding author: J. M. W. Wallace, fax +44 2870123023, email j.wallace@ulster.ac.uk

Abbreviations: 25(OH)D, 25-hydroxycholecalciferol; FM, fat mass; FFMI, fat-free mass index; FMI, fat mass index; FFM, fat-free mass; PTH, parathyroid hormone; WAL, waist action level; WC, waist circumference

0Comments