title: A systematic review of the interrelation between diet- and surgery-induced weight loss and vitamin D status.
abstract: Obesity is a major global health problem and has been associated with vitamin D deficiency. Intentional weight loss may alter vitamin D status and, conversely, vitamin D supplementation has been hypothesized to aid in weight loss. A systematic literature search in PubMed/Medline identified 3173 articles of which 37 studies (randomized controlled trials (RCT) [n=17], non-RCTs [n=20]) are summarized as effect of: (I) diet-induced weight loss on vitamin D status (n=7), (II) vitamin D supplementation on diet-induced weight loss (n=11), (III) surgery-induced weight loss on vitamin D status (n=15), and (IV) vitamin D supplementation after surgery-induced weight loss on vitamin D status (n=5). While all studies on the effect of diet-induced weight loss on vitamin D status have consistently reported increased vitamin D levels, the targeted percentage of weight loss that is necessary for an increase has varied between 5% and >10%. N=11 RCTs testing the effect of vitamin D supplementation observe that vitamin D supplementation does not result in increased weight loss, but may affect body fat loss. Vitamin D deficiency and subsequent hyperparathyroidism have been detected in post-surgery patients, and there is evidence that vitamin D supplementation improves these post-surgery complications. We review the current evidence addressing the role of vitamin D status and supplementation in diet- and surgery-induced weight loss. Subsequently, we highlight gaps in current research and suggest directions for future research including differences in vitamin D supplementation dosages, indoor vs. outdoor exercise, and the assessment of vitamin D status in different body pools.
authors.affiliation: Huntsman Cancer Institute, Population Sciences, Salt Lake City, UT; Department of Population Health Sciences, University of Utah, Salt Lake City, UT; University Hospital Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Caroline
authors.initials: C
authors.lastname: Himbert
authors.affiliation: Huntsman Cancer Institute, Population Sciences, Salt Lake City, UT; Department of Population Health Sciences, University of Utah, Salt Lake City, UT.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Ose
authors.affiliation: Huntsman Cancer Institute, Population Sciences, Salt Lake City, UT; Department of Population Health Sciences, University of Utah, Salt Lake City, UT; Exercise Immunology, Physical Education and Sport Sciences Department, Tarbiat Modares University, Tehran, Iran.
authors.forename: Mahmoud
authors.initials: M
authors.lastname: Delphan
authors.affiliation: Huntsman Cancer Institute, Population Sciences, Salt Lake City, UT; Department of Population Health Sciences, University of Utah, Salt Lake City, UT. Electronic address: neli.ulrich@hci.utah.edu.
authors.forename: Cornelia M
authors.initials: CM
authors.lastname: Ulrich
mesh_terms: D000273:Adipose Tissue / Q000378:metabolism; D019587:Dietary Supplements; D006801:Humans; D009765:Obesity / Q000097:blood / Q000150:complications / Q000188:drug therapy / Q000601:surgery; D011183:Postoperative Complications / Q000097:blood / Q000188:drug therapy; D014807:Vitamin D / Q000097:blood / Q000494:pharmacology / Q000627:therapeutic use; D014808:Vitamin D Deficiency / Q000097:blood / Q000150:complications / Q000188:drug therapy; D014815:Vitamins / Q000097:blood / Q000494:pharmacology / Q000627:therapeutic use; D015431:Weight Loss
chemical_list: D014815:Vitamins; D014807:Vitamin D
keywords: Bariatric surgery; Cancer; Diet; Obesity; Vitamin D; Weight loss