Ultraviolet radiation suppresses obesity and symptoms of metabolic syndrome independently of vitamin D in mice fed a high-fat diet.

Author: Geldenhuys S1, Hart PH1, Endersby R1, Jacoby P1, Feelisch M2, Weller RB3, Matthews V4, Gorman S5.
1Telethon Kids Institute, The University of Western Australia, Perth, Western Australia, Australia. 2Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton General Hospital, Southampton, U.K. 3University of Edinburgh, MRC Centre for Inflammation Research, Edinburgh, Scotland. 4Laboratory for Metabolic Dysfunction, Harry Perkins Institute of Medical Research, Centre for Medical Research, The University of Western Australia, Perth, Western Australia, Australia. 5Telethon Kids Institute, The University of Western Australia, Perth, Western Australia, Australia shelley.gorman@telethonkids.org.au.
Conference/Journal: Diabetes.
Date published: 2014 Nov
Other: Volume ID: 63 , Issue ID: 11 , Pages: 3759-69 , Special Notes: doi: 10.2337/db13-1675 , Word Count: 238

The role of vitamin D in curtailing the development of obesity and comorbidities such as the metabolic syndrome (MetS) and type 2 diabetes has received much attention recently. However, clinical trials have failed to conclusively demonstrate the benefits of vitamin D supplementation. In most studies, serum 25-hydroxyvitamin D [25(OH)D] decreases with increasing BMI above normal weight. These low 25(OH)D levels may also be a proxy for reduced exposure to sunlight-derived ultraviolet radiation (UVR). Here we investigate whether UVR and/or vitamin D supplementation modifies the development of obesity and type 2 diabetes in a murine model of obesity. Long-term suberythemal and erythemal UVR significantly suppressed weight gain, glucose intolerance, insulin resistance, nonalcoholic fatty liver disease measures; and serum levels of fasting insulin, glucose, and cholesterol in C57BL/6 male mice fed a high-fat diet. However, many of the benefits of UVR were not reproduced by vitamin D supplementation. In further mechanistic studies, skin induction of the UVR-induced mediator nitric oxide (NO) reproduced many of the effects of UVR. These studies suggest that UVR (sunlight exposure) may be an effective means of suppressing the development of obesity and MetS, through mechanisms that are independent of vitamin D but dependent on other UVR-induced mediators such as NO.
© 2014 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered.
PMID: 25342734