Effect of high dose vitamin D supplementation on cardiometabolic risk factors in subjects with metabolic syndrome: a randomized controlled double blind clinical trial
PurposeThe evidence in support of the effect of vitamin D deficiency on cardiovascular diseases is inconsistent. The objective of this randomized, controlled, double blind study was to assess the effect of high dose vitamin D supplementation on cardiometabolic risk factors in subjects with metabolic syndrome.MethodsEighty subjects were randomized to receive 50,000 IU vitamin D or matching placebo weekly for 16 weeks. Fasting blood sugar, homeostasis model assessment of insulin resistance, insulin sensitivity (Quicki) serum lipid profiles (low density lipoprotein cholesterol, high density lipoprotein cholesterol, triglyceride (TG) and total cholesterol) anthropometric factors and blood pressure were assessed before and after intervention. Dietary intake and sun exposure were also determined. The trial was registered at http:/www.irct.ir (code: IRCT201409033140N14).ResultsParticipants were 40.49 5.04 years and 49 male. All of the intervention group and 97 of placebo group were vitamin D deficient or insufficient (25 hydroxyvitamin D <75 nmol/L) After intervention, serum 25(OH)D concentration was increased by 61.93 nmol/L in intervention group, while it was decreased in placebo group (p 0.001) There was a significant change in TG concentration after 4 months (p 0.001) Other metabolic or anthropometric factors did not change significantly (p 0.05).ConclusionSupplementation with high dose vitamin D for 4 months improved vitamin D status and decreased TG levels in subjects with metabolic syndrome. However, it did not have any beneficial effects on other cardiometabolic risk factors; this might be due to the inadequate vitamin D status attained in this study which was conducted in a severely deficient region.
Journal of Endocrinological Investigation