Rune Holt, Joachim Holt, Mads Joon Jorsal, Rasmus Michael Sandsdal, Simon B K Jensen, Sarah Byberg, Christian Rimer Juhl, Julie Rehné Lundgren, Charlotte Janus, Bente Merete Stallknecht, Jens Juul Holst, Anders Juul, Sten Madsbad, Martin Blomberg Jensen, Signe Sørensen Torekov
The Journal of Clinical Endocrinology & Metabolism, Volume 110, Issue 8, August 2025, Pages 2215–2224
https://doi.org/10.1210/clinem/dgae775
Abstract
Context
Obesity is associated with low vitamin D status -, and recent studies have suggested a difference in vitamin D metabolism between females and males.
Objective
The aim of this study was to investigate the effects of weight loss on vitamin D status in individuals with obesity, and secondarily, whether vitamin D metabolism differs between women and men.
Methods
Secondary analysis from a randomized placebo-controlled trial, designed to investigate the efficacy of 52 weeks of treatment with either liraglutide, exercise, or both combined compared with placebo on weight loss maintenance after an 8-week low-calorie diet-induced weight loss in 195 individuals with obesity (body mass index 32–43 kg/m2).
Results
The low-calorie diet-induced weight loss resulted in an increase in serum 25-hydroxyvitamin D (25(OH)D) in both women and men [12 nmol/L (95% confidence interval [CI] 9–15) and 13 nmol/L (95% CI 8–17); P < .001 for both]. Women who experienced a further weight loss during the 52 weeks of intervention had an increase in serum 25(OH)D compared with women regaining weight [14 nmol/L (95% CI 6–22); P = .001]. Interestingly, women experiencing further weight loss at week 52 had a lower serum 25(OH)D at baseline compared with women regaining weight [54 nmol/L (SD 19) vs 70 nmol/L (SD 25), P < .001.]
Conclusion
Weight loss induced by a low-calorie diet resulted in an increase in serum 25(OH)D in both women and men. Only in women, further weight loss had an additional beneficial impact on vitamin D. Additionally, initial low serum 25(OH)D was associated with successful weight loss maintenance in women but not men.
Trial registration
ClinicalTrials.gov number: NCT04122716