Salt preference of nursing mothers is associated with earlier cessation of exclusive breastfeeding

Sex Differences in Salt Appetite: Perspectives from Animal Models and Human Studies

Salt ingestion by animals and humans has been noted from prehistory. The search for salt is largely driven by a physiological need for sodium. There is a large body of literature on sodium intake in laboratory rats, but the vast majority of this work has used male rats. The limited work conducted in both male and female rats, however, reveals sex differences in sodium intake. Importantly, while humans ingest salt every day, with every meal and with many foods, we do not know how many of these findings from rodent studies can be generalized to men and women. This review provides a synthesis of the literature that examines sex differences in sodium intake and highlights open questions. Sodium serves many important physiological functions and is inextricably linked to the maintenance of body fluid homeostasis. Indeed, from a motivated behavior perspective, the drive to consume sodium has largely been studied in conjunction with the study of thirst. This review will describe the neuroendocrine controls of fluid balance, mechanisms underlying sex differences, sex differences in sodium intake, changes in sodium intake during pregnancy, and the possible neuronal mechanisms underlying these differences in behavior. Having reviewed the mechanisms that can only be studied in animal experiments, we address sex differences in human dietary sodium intake in reproduction, and with age.

The Effects of Mild Gestational Hyperglycemia on Exclusive Breastfeeding Cessation

Gestational diabetes increases the risk of a range of adverse perinatal outcomes, including breastfeeding failure, but the best cut-off point for gestational diabetes is unknown. The purpose of this study was to evaluate the association between mild gestational glucose tolerance impairment and the early cessation of exclusive breastfeeding (EBF). This is an observational study of 768 women with full term pregnancies that were screened for gestational diabetes at 24–28 weeks gestation. Subjects were divided into two groups: those with a normal 1-h glucose challenge test and those with an elevated 1-h glucose challenge test but still did not qualify for gestational diabetes. We constructed multivariable logistic regression models using data from 616 women with normal gestational glucose tolerance and 152 women with an isolated positive 1-h glucose challenge test. The risk of early exclusive breastfeeding cessation was found to increase in women with mildly impaired glucose tolerance during pregnancy (adjusted OR, 1.65; 95% CI: 1.11, 2.45). Risks of early EBF cessation were also independently associated with the amount of neonatal weight loss and admission to the neonatal ward. Instead, parity was associated with a decreased risk for shorter EBF duration. Insulin resistance—even in the absence of gestational diabetes mellitus—may be an impeding factor for EBF.