Περίληψη:
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. © 2021, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.
Συγγραφείς:
Karampela, I.
Sakelliou, A.
Vallianou, N.
Christodoulatos, G.-S.
Magkos, F.
Dalamaga, M.
Λέξεις-κλειδιά:
25 hydroxyvitamin D; bisphosphonic acid derivative; calcitriol; calcium; corticosteroid; estradiol; fatty acid synthase; glutathione; heparin; ketoconazole; leptin; osteocalcin; parathyroid hormone; prolactin; prostaglandin; sunscreen; testosterone; thiazide diuretic agent; vitamin D; vitamin D receptor; vitamin D, adipose tissue; bariatric surgery; body composition; body mass; body weight; body weight loss; bone density; caloric restriction; cardiometabolic risk; chemiluminescence immunoassay; chemoluminescence; enzyme linked immunosorbent assay; fat mass; food intake; gastric banding; gene expression; high performance liquid chromatography; human; hypercalcemia; hyperparathyroidism; hyperthyroidism; kidney disease; lipid storage; non insulin dependent diabetes mellitus; nonhuman; obesity; ovary polycystic disease; physical activity; protein expression; radioimmunoassay; randomized controlled trial(topic); Review; seasonal variation; sleeve gastrectomy; upregulation; vitamin D deficiency; vitamin D metabolism; waist circumference; waist hip ratio; dietary supplement; drug effect; factual database; metabolism; obesity; vitamin D deficiency, Adipose Tissue; Adiposity; Bariatric Surgery; Body Weight; Databases, Factual; Dietary Supplements; Humans; Obesity; Vitamin D; Vitamin D Deficiency; Weight Loss
