Improvement of vitamin D status resulted in amelioration of biomarkers of systemic inflammation in the subjects with type 2 diabetes

Both vitamin D deficiency and inflammation have been linked to cardiovascular disease (CVD), the major cause of death in diabetes. In this study, the effects of daily intake of vitamin D-fortified yogurt drink (doogh) on systemic inflammatory biomarkers in subjects with type 2 diabetes (T2D) were investigated. In this 12-week randomized controlled clinical trial (RCT), T2D subjects received either plain doogh (PD containing 170mg calcium and no detectable vitamin D/250mL, n1=50) or vitamin D3-fortified doogh (FD containing 170 mg calcium and 500 IU/250mL, n2=50) twice a day. Glycemic status, body fat mass (FM) and systemic inflammatory biomarkers including serum hsCRP, serum amyloid A (SAA), interleukin (IL)-2, IL-6, IL-10 and tumor necrosis factor (TNF)-α were evaluated at the beginning and after the intervention. Data were expressed as either mean±SD or median (interquartile range [IQR]) whenever they had either normal or non-normal distribution, respectively. In the FD group, compared to the PD group, a significant increase in serum 25 (OH)D was accompanied by significant changes in TNF-α (-57.9 (-264.6) vs. +106.3 (683.2), p=0.044), IL-6 (-6.3 (-69.2), p=0.002), hsCRP (-0.39 (-1.50) vs. +0.8 (1.52), p<0.001), SAA (-14.2±44.5 vs. +5.6±37.5 mg/L, p=0.022) and IL-10 (+38.7±157.0 vs. -51.9±165.2 ng/L, p=0.013). The between-group differences of hsCRP, SAA and IL-6 changes remained significant even after controlling for changes QUICKI (p<0.001, p<0.001 and p=0.009 respectively). Improvement of vitamin D status of T2D subjects resulted in amelioration of the systemic inflammatory markers. This may have preventive implications against CVD and other diabetic complications. This trial was registered at ClinicalTrials.gov as NCT01236846.