Metabolic syndrome and insulin resistance in overweight/obese women in early postpartum
Metabolic syndrome includes several metabolic and hormonal disorders, such as abdominal obesity, insulin resistance, and lower blood ghrelin. Women with breastfeeding history exhibit a reduced risk for metabolic syndrome in later life. The purpose of aim 1 was to determine the incidence of metabolic syndrome in low income, overweight/obese women in early postpartum and to assess its relationship to lactation status. It has been found that the incidence of metabolic syndrome is much higher in formula feeding women than that of the breastfeeding ones (44.3% vs. 22.4%, p < 0.01). The breastfeeding mothers had reduced triglycerides (109.07 mg/dl vs. 143.10 mg/dl, p < 001) and elevated serum high-density lipoprotein (HDL)-cholesterol (58.59 mg/dl vs. 51.76 mg/dl, p < 0.01). The goal of aim 2 was to explore associations between ghrelin, metabolic syndrome and infant feeding methods in low income, overweight/obese women in early postpartum. In our study, the breastfeeding mothers in early postpartum had higher plasma ghrelin, as compared to those who formula fed (584.73 pg/ml vs. 450.77 pg/ml, p < 0.01). Additionally, it is found that plasma ghrelin was negatively associated with incidence and numbers of risk factors for metabolic syndrome, before and after controlling for body mass index (BMI). After adjusting for ghrelin in logistic regression analyses, significant relationships between lactation status and metabolic syndrome disappeared. Thus, the protective function of breastfeeding against metabolic syndrome in overweight/obese women in early postpartum may related to the plasma ghrelin values. The purpose of aim 3 was to detect the influence of weight loss on insulin resistance and plasma adiponectin, zinc (Zn), manganese (Mn) and copper (Cu) in low income, overweight/obese women in early postpartum. After an eight-week weight loss intervention, plasma levels of adiponectin, Zn and Mn were significantly enhanced, and plasma concentrations of insulin (7.53±0.56 vs. 6.23±0.49, p <0.01) and insulin resistance (1.84±0.15 vs. 1.44±0.12, p <0.01) were reduced. The increase of adiponectin, Zn and Mn was positively associated with weight reduction. However, the plasma Cu was not significantly affected. The relationships between weight loss and reduced insulin resistance disappeared after adjusting the increases of adiponectin, Zn and Mn during weight loss. Thus, weight loss had beneficial effects on insulin resistance, plasma values of adiponectin Zn and Mn. It is plausible that the influence of weight loss on insulin resistance may be associated with improvements of plasma of adiponectin, Zn and Mn. Collectively, the results of this study demonstrate the important benefits of breastfeeding on prevention of metabolic syndrome in overweight/obese women in early postpartum. This study also emphasizes the influence of ghrelin on risk factors of metabolic syndrome and lactation status.