Northern Illinois University, USA
Judith M Lukaszuk has completed her MS and PhD at the University of Pittsburgh. She is a registered and licensed Dietitian and Nutritionist. She works at Northern Illinois University as a Nutrition Professor and is the Didactic Program Director. She has published in the area of sports nutrition and integrative nutrition.
Excess adipose tissue may lead to sequestrating of vitamin D making it less available for use in the body. This study was conducted to determine if overweight individuals (BMI>25) have insufficient (<30 ng/mL) levels of 25-hydroxy vitamin D (25-OH D) and if so would serum levels respond to exogenous supplementation. Sixty-four overweight (BMI 31.11±5.01) women were randomly assigned in a double blind manner to receive either 5000 IU of vitamin D3 (D3) (n=31) or a maltodextrin placebo (PL) (n=33). Serum 25 (OH) D concentrations were measured by finger stick analyses at baseline and after an eight-week supplementation period. The results of this study show that on day one of the study both D3 and PL group had insufficient levels of vitamin D (mean±SD) 24.03±9.78 ng/mL and 22.48±9.69 ng/mL respectively. After eight weeks of supplementation the D3 group 25 (OH) D level rose to a mean of ⱡ 43.57±10.87ng/mL (ⱡ p<0.001) versus the PL group whose 25 (OH) D level remained statistically unchanged 24.30±8.96 ng/mL. Overweight women had insufficient vitamin D levels prior to supplementation. Following supplementation with 5000 IU of vitamin D3 all subjects’ 25 (OH) D levels rose to a sufficient level (≥30 ng/mL). This suggests that women who are overweight or obese may need a vitamin D dosage which slightly exceeds the Institute of Medicines recommendation of 4000 IU per day and that supplementation may improve serum levels.