Vitamin D supplementation, the metabolic syndrome and oxidative stress in obese children.
BACKGROUND
Previous studies suggest that vitamin D may play a role in cardiovascular and metabolic health. Oxidative stress has also been implicated in the development of cardiovascular disease. Evidence suggests that vitamin D deficiency may contribute to the occurrence of oxidative stress. This study aimed to determine whether treatment and correction of vitamin D deficiency in obese children led to changes in their metabolic profile, independent of changes in adiposity. In addition, we aimed to determine whether vitamin D deficiency and oxidative stress are causally related in obese children.


METHODS
In the retrospective arm, chart review identified 32 obese children who experienced normalization of vitamin D deficiency or insufficiency with vitamin D supplementation. We then correlated laboratory and anthropometric data with vitamin D levels. In the prospective arm of the study, urinary 8-isoprostane and hydrogen peroxide were measured before and after correction of vitamin D deficiency/insufficiency and correlated to vitamin D levels in seven patients.


RESULTS
In our predominantly Hispanic population of obese children in an urban setting, we demonstrated a cause-effect relationship between vitamin D deficiency and oxidative stress. In contrast, we found no association between vitamin D status, adiposity, and markers of insulin sensitivity, nor any effect of vitamin D treatment on the same parameters.


CONCLUSIONS
These discordant findings suggest a differential effect of vitamin D on cardiovascular risk factors such as oxidative stress and insulin resistance. To confirm these findings, further prospective studies with larger sample size and longer follow-up are warranted.
['Grunwald|Tal|T|', 'Fadia|Shruti|S|', 'Bernstein|Bruce|B|', 'Naliborski|Matthew|M|', 'Wu|Shufang|S|', 'Luca|Francesco De|F|']
D000293:Adolescent D000328:Adult D002648:Child D002675:Child, Preschool D019587:Dietary Supplements D005260:Female D005500:Follow-Up Studies D006801:Humans D008297:Male D024821:Metabolic Syndrome D009765:Obesity D018384:Oxidative Stress D011379:Prognosis D012189:Retrospective Studies D012307:Risk Factors D014807:Vitamin D D014808:Vitamin D Deficiency D055815:Young Adult
vitamin D metabolism obesity