Effects of a 1-year supplementation with cholecalciferol on interleukin-6, tumor necrosis factor-alpha and insulin resistance in overweight and obese subjects

• Published in: Cytokine (Philadelphia, Pa.) Vol. 60; no. 3; pp. 870 - 874
• Main Authors: Beilfuss, Julia, Berg, Vivian, Sneve, Monica, Jorde, Rolf, Kamycheva, Elena
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.12.2012
• Subjects: Adult; Aged; animals; Autoimmune diseases; biomarkers; Biomarkers - blood; blood serum; Body weight; C-reactive protein; C-Reactive Protein - metabolism; Cancer; cholecalciferol; Cholecalciferol - administration & dosage; Cholecalciferol - therapeutic use; Cytokines; Dietary Supplements; Female; Humans; Immune response; Inflammation; Insulin; Insulin Resistance; Interleukin 6; Interleukin-6 - blood; Male; metabolic diseases; Metabolic disorders; metabolic syndrome; Middle Aged; Obesity; Obesity - blood; Obesity - drug therapy; Overweight - blood; patients; Serum levels; Supplementation; TNF-α; Tumor necrosis factor- alpha; Tumor Necrosis Factor-alpha - blood; Vitamin D; vitamin status; Young Adult; Obesity; Insulin resistance; TNF-α; Vitamin D; Interleukin-6
• DOI: 10.1016/j.cyto.2012.07.032
• ISSN: 1043-4666

► We proposed that high dose vitamin D supplementation influences cytokine levels. ► The corresponding effect of vitamin D on insulin resistance was also proposed. ► 332 obese subjects underwent a 12months randomised intervention with vitamin D. ► Positive significant association between TNF-α and insulin resistance was found. ► Vitamin D supplementation had a lowering effect on IL-6 levels. Insufficient vitamin D status has been linked to autoimmune diseases, cancer and metabolic disorders, like obesity and insulin resistance. In vitro and animal studies suggest that vitamin D may play a crucial role in immune activation and inflammation. The relation between vitamin D and pro-inflammatory cytokines is not completely established. Furthermore, it is not known if the effect of vitamin D on entities of metabolic syndrome is mediated through its effect on cytokines or other biomarkers. The objectives of this study were to investigate if there is a relationship between vitamin D status and such pro-inflammatory cytokines as tumor necrosis factor-alpha (TNF-α), interleukin 6 (IL-6) and high sensitive C-reactive protein (hs-CRP) in patients with overweigh and obesity. We also proposed that the intervention with high dose of cholecalciferol may have effect on the cytokine levels and result in corresponding changes in the measures of insulin resistance (HOMA-IR and QUICKI). Serum levels of IL-6, TNF-α and hs-CRP were measured in 332 overweight and obese subjects who completed a 1-year randomised intervention with either 40,000IU vitamin D (cholecalciferol) per week or 20,000IU vitamin D per week, or placebo. We found significant associations between IL-6, TNF-α, vitamin D and insulin resistance indices at baseline. One year intervention with vitamin D decreased serum IL-6 levels; however hs-CRP levels were significantly increased. Neither measures of insulin resistance, nor TNF-α were influenced by a 1-year vitamin D supplementation.