The Relationship Between Serum Ionized Magnesium Concentrations and Diastolic Blood Pressure in Overweight and Obese Adults (P24-040-19). (13th June 2019) - Cheung, May
Abstract: Objectives: Adequate magnesium (Mg) status has been shown to be associated with improved cardiometabolic health. Magnesium status is commonly assessed by measuring serum concentrations of Mg in clinical settings; however, serum concentrations of ionized Mg (iMg) is a better indicator of bioavailable Mg status. Few researchers have assessed iMg as a measure of Mg status due to difficulties in sample preparation and storage. Furthermore, the influence of iMg concentrations on cardiometabolic health is scarce. The objective of this study was to investigate whether changes in iMg induced by supplementation may affect cardiometabolic health parameters in an overweight and obese (owt/ob) population. Methods: Participants were randomly assigned to receive a daily dose of magnesium (360 mg Mg glycinate) and/or vitamin D (1000 IU D3 ) supplements or placebo in a 12-week double-blinded, randomized ongoing clinical trial. Because this is an ongoing study, the analyses are still not unblinded. Blood samples were obtained for analyses of serum 25-hydroxyvitamin D (s25OHD), parathyroid hormone, total triglyceride, insulin, fasting glucose and inflammatory cytokine concentrations to determine cardiometabolic risk factors. Serum concentration of iMg were assessed by a NOVA-8 analyzer with an ion sensitive electrode method, using serum samples within 5 hours of initial venipuncture for each participant. Seated blood pressure was assessed with an automated oscillometric device on the right arm, according to the American Heart Association Guidelines for In-Clinic Blood Pressure Measurement. Results: A total of 66 Owt/Ob adults, 29 to 65 years of age, with a body mass index (BMI) between 24 to 41 kg/m 2, completed all study measurements. Mean iMg concentrations at baseline were 0.543 ± 0.055 mmol/L. There was a significant negative correlation between change in iMg and change in diastolic blood pressure ( r = −0.299, P = 0.039). Conclusions: Improvement in Mg status may be associated with lowering of diastolic blood pressure. Whether changes in iMg status may affect overall cardiometabolic health is inconclusive at this point. Funding Sources: American Heart Association.