The impact of maternal care and blood glucose availability on the cortisol stress response in fasted women

Abstract

Individuals with a history of low maternal care (MC) frequently present a blunted, yet sometimes also show an increased cortisol stress response. Fasted individuals with low blood glucose levels who are exposed to acute stress typically show an attenuated response pattern in this endocrine marker. Despite well-documented metabolic dysregulations after low MC, a possible interaction of both factors has not been investigated yet. Here, we examined the effects of MC and blood glucose concentration on various aspects of the stress response. Fasted women (N = 122, mean_age = 22.12, sd_age = 2.56) who experienced either very high, high, or low MC (based on the Parental Bonding Instrument) were randomly assigned to consume grape juice (condition sugar), or water (condition water) prior to being exposed to the Trier-Social-Stress-Test for groups. Salivary cortisol and alpha amylase, blood glucose, and mood ratings were assessed repeatedly. Using multilevel mixed models, we replicated the boosting effect of glucose on the cortisol stress response. While we found neither an effect of MC, nor an interaction between MC and blood glucose availability on the cortisol stress response, we observed an effect of MC on the amylase stress response. We discuss the results in the light of links between various stress/energy systems that possibly mediate health-related MC effects.

Keywords: Cortisol; Early life stress; Glucose; Maternal care; Stress.

Fig. 1

Overview of the study procedure: The experimental manipulation involved drinking 400 ml of water, or 400 ml of grape juice (containing 64 g of glucose), stress was induced using a modified version of the Trier Social Stress Test for Groups (TSST-G)

Fig. 2

Changes in blood glucose levels over time (i), and in response to the drink (ii) per experimental condition (values are depicted as mean ± SE)

Fig. 3

Cortisol (a) and alpha amylase (b) stress trajectories over time (i) and stress reactivity in response to the stressor (by means of the area under the response curve; AUCi) in the very high, high, and low maternal care (MC) groups per experimental condition (glucose, water) (values are depicted as mean ± SE): looking at cortisol trajectories (a, i), we found a significant Time³ × Drink interaction (p = 0.012), but no support for a Time³ × Drink × MC interaction; for alpha amylase trajectories (b, i), we found a significant Drink × MC interaction (p = 0.003)