Can Bone Regulating Hormones and Nutrients Characterize the Metabolically Healthy Obese Phenotype?

The term Metabolically healthy obese (MHO) phenotype has been used to describe those who present with a benign metabolic profile despite excess adiposity. These individuals are obese but are either completely free of metabolic abnormalities or have less than three components of metabolic syndrome. Previous studies suggest that bone regulating hormones and nutrients, such as parathyroid hormone (PTH), 25‐hydroxyvitamin D (25OHD), estrogen, osteocalcin, vitamin D, calcium and magnesium (Mg) influence overall energy metabolism. In this study, we aim to determine whether bone regulating hormones and nutrients can help characterize the MHO phenotype. We hypothesize that adequate Mg status, higher serum 25OHD and lower serum PTH concentrations are variable that could be included in the characterization of the MHP phenotype. A total of 27 overweight or obese adults (BMI 25–40 kg/m 2 ) were recruited. Measurements were obtained for ionized Mg, serum 25OHD, serum PTH, body fat percentage, trunk fat percentage, total fat mass, blood pressure, glycemic indices, lipid profile, and pro‐inflammatory cytokines in order to determine the metabolic factors differentiating MHO vs metabolically unhealthy obese (MUO) in this sample. Based on the presence of metabolic abnormalities, participants were classified as MHO (n=13) or MUO (n=14). Results showed no significant difference in mean age between the MHO group and MUO group (Mean age : 32.6 ± 9.2 yr). As expected, serum insulin concentrations and diastolic BP were lower in the MHO group compared to the MUO group (p < 0.04). In addition, triglyceride and c‐reactive protein concentrations did not differ between groups. Dietary Mg intake tended to be higher in the MHO group (270.4 ± 181.7 mg/day) than the MUO group (195.4 ± 88.9 mg/day). Ionized Mg concentration was significantly higher (p < 0.04) in the MHO group than in the MUO group. Serum 25OHD concentrations did not differ between groups, while serum PTH concentrations were significantly higher (p < 0.02) in the MUO group (61.8 ± 25.9 pg/mL) than the MHO group (40.2 ± 11.5 pg/mL). Serum osteocalcin and serum c‐telopeptide collagen concentrations also tended to be higher in the MHO compared to the MUO group. In summary the MHO phenotype had a better magnesium status, lower serum PTH levels and higher serum levels of bone turnover markers, some of which have shown to regulate energy metabolism. Early recognition of the alterations in these bone regulating hormones and nutrients can be a potential target for intervention or prevention of metabolic abnormalities in the obese population. Support or Funding Information American Heart Association‐ Scientist Development Grant‐ 16SDG27050002 to Deeptha Sukumar