Vitamin D and obesity: Current evidence and controversies

Research output: Contribution to journalReviewpeer-review

  • Irene Karampela
  • Alexandra Sakelliou
  • Natalia Vallianou
  • Gerasimos-Socrates Christodoulatos
  • Magkos, Faidon
  • Maria Dalamaga

Purpose of review: Evidence from observational studies suggests that obesity is associated with low vitamin D. As both obesity and hypovitaminosis D present an alarmingly increased prevalence worldwide, there is an intense research interest to clarify all aspects of this association. This review summarizes current evidence from meta-analyses investigating vitamin D status in obesity, including the effects of weight loss and bariatric surgery on vitamin D status and the outcomes of vitamin D supplementation on body weight. We also discuss potential pathophysiologic mechanisms and important controversies.

Recent findings: Data from meta-analyses consistently support an inverse association of vitamin D levels with body weight. However, the impact of weight loss on improving vitamin D status is small, while studies on the supplementation with vitamin D after bariatric surgery have shown conflicting results regarding vitamin D status. Moreover, interventional studies do not support a beneficial effect of vitamin D supplementation on body weight. These findings warrant a cautious interpretation due to important methodological limitations and confounding factors, such as high heterogeneity of studies, variable methods of determination of vitamin D and definition of deficiency/insufficiency, use of various adiposity measures and definitions of obesity, and inadequate adjustment for confounding variables influencing vitamin D levels. The underlying pathogenetic mechanisms associating low vitamin D in obesity include volumetric dilution, sequestration into adipose tissue, limited sunlight exposure, and decreased vitamin D synthesis in the adipose tissue and liver. Experimental studies have demonstrated that low vitamin D may be implicated in adipose tissue differentiation and growth leading to obesity either by regulation of gene expression or through modulation of parathyroid hormone, calcium, and leptin. 

Summary: Obesity is associated with low vitamin D status but weight loss has little effect on improving this; vitamin D supplementation is also not associated with weight loss. Evidence regarding vitamin D status after bariatric surgery is contradicting. The link between vitamin D and obesity remains controversial due to important limitations and confounding of studies. More research is needed to clarify the complex interplay between vitamin D and adiposity.

Original languageEnglish
JournalCurrent Obesity Reports
Volume10
Issue number2
Pages (from-to)162-180
Number of pages19
ISSN2162-4968
DOIs
Publication statusPublished - 2021

    Research areas

  • Faculty of Science - Adipose tissue, Body mass index, Hypovitaminosis D, Obesity, Vitamin D, 25(OH)D

ID: 259508044