Vitamins D and K Effects on Vascular Function in Obese Adults.

Overweight and obesity are public health issues of epidemic proportions nowadays. They constitute risk factors for several chronic diseases with vascular, metabolic, and inflammatory changes. Adequate serum levels of vitamin D are correlated with good cardiovascular and metabolic health, since its deficiency and insufficiency (highly prevalent in obesity) have an inverse correlation. Likewise, vitamin K, especially K2, is related to the reduction of arterial stiffness, suppression of the inflammation in the vascular wall, favorable action on the lipid profile, whereas insufficiency is related to increased cardiovascular risk. The combined use of vitamin D and K aiming to reduce cardiovascular risk has been studied, however, the results of randomized clinical trials are still controversial. This prospective, randomized, placebo-controlled, double-blind trial aims to evaluate the effect of supplementation of vitamins D3 and K2-MK7 on vascular function, sympathetic tone, metabolic biomarkers and inflammatory factors in a population of overweight or obese adults and serum levels of deficient or insufficient vitamin D. Individuals of both sexes, aged between 40 and 70 years, body mass index (BMI) ≥ 25 and \< 40 kg/m² and vitamin 25OHD3 \<30 ng/ml will be randomized into 3 groups (A/B/C) to receive supplementation (Placebo/VitD3 7000 IU/VitD3 7000IU+K2-MK7-180mcg) daily for 16 weeks. Individuals will be rated at 4 visits namely:

• V0 screening according to inclusion and exclusion criteria; clinical, anthropometry and electrical bioimpedance, laboratory and vascular evaluation before supplementation;
• V1 supplementation begins;
• V2 after 8 weeks;
• V3 at the end of the intervention. The laboratory evaluation consists of blood count, biochemistry, electrolytes, glucose, lipid, liver and thyroid profiles, vitamin D3 and parathyroid hormone, in addition to the urinary excretion of calcium and creatinine. Sympathetic tone is assessed by a frequency meter (Polar® Verity Sense), arterial stiffness by measuring the pulse wave velocity by oscillometry (Mobil-O-Graph®) and endothelium function by measuring post-occlusion microvascular reactivity using laser speckle contrast image-LSCI.