Are Breast-fed Infants More Resilient? Feeding Method and Cortisol in Infants

doi:10.1016/j.jpeds.2008.09.025

The Journal of Pediatrics

Volume 154, Issue 3, March 2009, Pages 452-454

https://doi.org/10.1016/j.jpeds.2008.09.025 Get rights and content

The effect of feeding method on stress hormone levels in infants is unknown. We studied infants from birth to 1 year and found salivary cortisol 40% higher in breast-fed infants compared with formula-fed infants. The higher cortisol levels among breast-fed children may be involved in the analgesic effect of breastfeeding.

Section snippets

Methods

We used hormone data from the Soy Estrogen and Development study, which had a mixed cross-sectional and longitudinal design, with 6 boys and 6 girls in 31 examination age intervals (<48 hours; weekly for 6 months; then monthly to 1 year). One third of the infants at each age interval were fed breast milk, cow's milk formula, or soy formula. Children were eligible if they had been born at term (37-41 weeks) and with birth weight 2500 to 4500 g, met one of the feeding definitions and age

Results

The serum cortisol level of the infants (5.12 μg/dL) was in the reference range (3-23 μg/dL) for infants younger than 12 months of age.⁷ The cortisol concentrations in saliva correlated strongly with cortisol measures in urine and blood, with Spearman's correlation coefficients of 0.96 and 0.93, respectively (Figure 1), further supporting the validity of the use of salivary cortisol as a primary measure of outcome.⁸

The baseline data (sex, age, birth weight and body length etc.) were balanced

Discussion

In this partly longitudinal study, we found that salivary cortisol was about 40% higher in breast-fed children throughout the first year of life. This finding was consistent after adjustment for infant size, sex, and race, was not accompanied by a significant difference in IL-6, and was true whether the formula-fed infants received cow's milk- or soy-based formula.

Saliva is often used for biologic assays in infants because of the ease of collection and now is preferred for cortisol analysis. We

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Basal cortisol concentrations related to maternal behavior during puppy development predict post-growth resilience in dogs
2021, Hormones and Behavior
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Second, puppy's cortisol concentrations may have been elevated as a result of suckling behavior. Breast milk is thought to have a stress-reducing effect (Carbajal et al., 2003; Shah et al., 2006); however, suckling behavior itself requires effort from the puppy, and this effort may increase adaptive behavior after growth (Bray et al., 2017a; Caldji et al., 1998; Cao et al., 2009; Liu et al., 1997). The lower the number of puppies, the higher the basal and post-separation cortisol concentrations, suggesting that they were well fed with their mother's milk.
A prolonged stress hyporesponsive period (SHRP) due to the mother's presence may delay the timing of glucocorticoid (GC) elevation in infants, thereby reducing the excessive stress response that would affect post-growth temperament. In dogs, the SHRP has been suggested to persist until postnatal week (PW) 4; therefore, PW 5, which SHRP may be prolonged by the mother dog, may be a critical point in the developmental stage of dogs to establish stress responsiveness. We conducted a long-term survey on the development of dogs to investigate i) whether the degree of the stress response at PW 5 is determined by maternal behavior and ii) whether it can predict post-growth stress responses and temperament in dogs. As a result, the offspring of mother dogs who had more delivery experience and exhibited more maternal behavior showed higher basal cortisol concentrations at PW 5. These offspring may have acquired less fear response as an individual trait and had relatively quick adaptability, albeit with high cortisol concentrations during exposure to novel environments post-growth, suggesting that high cortisol concentrations at PW 5 are linked to resilience post-growth. Basal cortisol concentrations at PW 7 were not affected by maternal variables and were not associated with cortisol response to novel environments post-growth. GCs are essential hormones that increase the probability of survival. Therefore, the high hypothalamic pituitary adrenal activities of the mother dogs and their offspring in this study may not immediately indicate negative states, and these results prompt a reconsideration of the role of GC in organisms.
Maternal influences on the glucocorticoid concentrations of human milk: The STEPS study
2019, Clinical Nutrition
Human milk (HM) contains a wide array of non-nutritive bioactive elements, including glucocorticoid hormones (glucocorticoid; cortisol and cortisone). The relationship between milk-borne glucocorticoids, measures of maternal health and patterns of breast-feeding is not yet established. This study was conducted to determine the influence of maternal and infant related biological and socio-demographic factors on the levels of glucocorticoids hormones in HM.
Samples were obtained from lactating mothers (n = 656) participating in the Finnish cohort the STEPS study (Steps to the Healthy Development and Well-being of Children) when the infants were 11.29 (±2.6) weeks of age. Glucocorticoids (both cortisol and cortisone) concentrations were measured using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Maternal demographics, biological and social factors were obtained using hospital records and self-reported diaries and questionnaires.
The majority of women reported that they were exclusively breastfeeding at the time of sample donation (51.2%). For all collected samples, cortisone (9.55 ± 3.44 ng/ml) was the predominant hormone and cortisol (7.39 ± 5.97 ng/ml) was present in all samples. Strong and positive correlation was found between cortisol and cortisone (r = 0.60, p=<0.0001). Cortisone was statistically different between overweight, normal and underweight women (p = 0.01) for cortisol no difference was seen (p = 0.96). Whilst, preterm birth (born before 37 week gestation) was positively associated with both cortisol (p = 0.04) and cortisone (p = 0.01). There was also a significant but weaker negative relationship between mothers educational status and cortisol (p = 0.05) and no effect was seen for cortisone (p = 0.82). Interestingly, no significant differences was found in glucocorticoid concentrations between exclusive and partial breastfeeding women.
HM contains glucocorticoids hormones. The concentrations are influenced by the varying maternal factors including maternal weight, preterm birth and maternal educational status, suggesting the possible role of maternal biological and social influences on milk hormonal composition. Interestingly, there was no influence of feeding patterns on HM glucocorticoids. Further analysis is required to fully explore the relationship with measures of maternal stress, including mother's glucocorticoid status.
Nutritional programming by glucocorticoids in breast milk: Targets, mechanisms and possible implications
2017, Best Practice and Research: Clinical Endocrinology and Metabolism
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Additionally, corticosterone was detectable in the serum of adrenalectomized pups fed with their own mother's milk [36]. In humans, a 40% higher salivary cortisol level was found among infants who were breastfed during one year in comparison with infants who were formula-fed [37]. Moreover, another study found that salivary cortisol concentration in infants correlated positively with the level in their mothers only in those who were breast-fed [38].
Vertical transmission of glucocorticoids via breast milk might pose a mechanism through which lactating women could prepare their infants for the postnatal environment. The primary source of breast-milk glucocorticoids is probably the systemic circulation. Research from our group showed that milk cortisol and cortisone concentrations follow the diurnal rhythm of maternal hypothalamus–pituitary–adrenal axis activity, with a higher abundance of cortisone compared to cortisol. Measurement of breast-milk glucocorticoid concentrations is challenging due to possible cross-reactivity with progestagens and sex steroids, which are severely elevated during pregnancy and after parturition. This requires precise methods that are not hindered by cross reactivity, such as LC–MS/MS. There are some data suggesting that breast-milk glucocorticoids could promote intestinal maturation, either locally or after absorption into the systemic circulation. Breast-milk glucocorticoids might also have an effect on the intestinal microbiome, although this has not been studied thus far. Findings from studies investigating the systemic effects of breast-milk glucocorticoids are difficult to interpret, since none took the diurnal rhythm of glucocorticoids in breast milk into consideration, and various analytical methods were used. Nevertheless, glucocorticoids in breast milk might offer a novel potential pathway for signal transmission from mothers to their infants.
Cortisol and DHEA in development and psychopathology
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Dehydroepiandrosterone (DHEA) and cortisol are the most abundant hormones of the human fetal and adult adrenals released as end products of a tightly coordinated endocrine response to stress. Together, they mediate short- and long-term stress responses and enable physiological and behavioral adjustments necessary for maintaining homeostasis. Detrimental effects of chronic or repeated elevations in cortisol on behavioral and emotional health are well documented. Evidence for actions of DHEA that offset or oppose those of cortisol has stimulated interest in examining their levels as a ratio, as an alternate index of adrenocortical activity and the net effects of cortisol. Such research necessitates a thorough understanding of the co-actions of these hormones on physiological functioning and in association with developmental outcomes. This review addresses the state of the science in understanding the role of DHEA, cortisol, and their ratio in typical development and developmental psychopathology. A rationale for studying DHEA and cortisol in concert is supported by physiological data on the coordinated synthesis and release of these hormones in the adrenal and by their opposing physiological actions. We then present evidence that researching cortisol and DHEA necessitates a developmental perspective. Age-related changes in DHEA and cortisol are described from the perinatal period through adolescence, along with observed associations of these hormones with developmental psychopathology. Along the way, we identify several major knowledge gaps in the role of DHEA in modulating cortisol in typical development and developmental psychopathology with implications for future research.
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2017, Nursing Outlook
The American Academy of Nursing has identified toxic stress in childhood as a health policy concern of high priority. Adult diseases (e.g., obesity, diabetes, hypertension and cardiovascular disease) should be viewed as developmental disorders that begin early in life that could be reduced with the alleviation of toxic stress in childhood. The provision of human milk/breastfeeding is an evidence-based intervention that may hold the greatest potential to mitigate the effects of toxic stress from the moment of birth. Assisting families to make an informed choice to initiate and continue breastfeeding from birth has the potential to address both the disparity in the quality of nutrition provided infants and the economic stress experienced by families who purchase formula. The Expert Panel on Breastfeeding endorses initiatives to improve the initiation, duration, and exclusivity of breastfeeding to mitigate the effects of toxic stress in this call to action for research to build the evidence to support these critical relationships.
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Research examining the relationship between breastfeeding and infant weight has generated conflicting results. Few studies account for significant covariates and many suffer methodological problems such as retrospective self-report. The current study aimed to investigate relationships between breastfeeding duration, infant weight and eating and positive maternal mealtime behaviours, whilst overcoming many of the limitations of previous research. Eighty-one women on low-risk maternity units gave informed consent and were visited at home at 1-week, 1-, 6- and 12-months postpartum. Infants included 45 males and 36 females (mean birth-weight 3.52 kg [SD 0.39]). Mothers and infants were weighed and measured and feeding information was recorded at each visit. Infant weight was converted to a standard deviation score (SDS), accounting for age and sex. Mothers reported infant eating behaviours at 12-months using the Children's Eating Behaviour Questionnaire and were observed feeding their infants solid food at home at 6- and 12-months. Partial correlations (covariates: maternal age, education, BMI, smoking during pregnancy, household income, infant birth weight SDS and age introduced to solid foods) revealed negative associations between breastfeeding duration and 1- to 6- and 1- to 12-month weight gain, and 6- and 12-month weight. Breastfeeding duration was also associated with a slower rate of infant eating and greater observed maternal vocalisations, appropriateness and sensitivity. Results support a dose-response relationship between breastfeeding and infant weight and suggest that breastfeeding may encourage the development of obesity-protective eating behaviours through learning to attend to internal hunger and satiety signals. Future research should investigate whether relationships between slowness in eating and weight extend to satiety responsiveness after infancy.

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: Supported by the Intramural Research Program of the NIH, National Institute of Environmental Health Sciences. Rao was supported by the NIH grant (No. 2 T 35 HD 007446) from the Society for Pediatric Research Summer Research Fellowship. The authors declare no conflicts of interest.

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Clinical and laboratory observationAre Breast-fed Infants More Resilient? Feeding Method and Cortisol in Infants

Section snippets

Methods

Results

Discussion

J Biochem Biophys Methods

Clin Biochem

Stress hormones: how do they measure up?

Biol Res Nurs

Stress reactivity and attachment security

Dev Psychobiol

Nature of love—simplified

Am Psychol

Breastfeeding or breast milk for procedural pain in neonates

Cochrane Database Syst Rev

Clinical and laboratory observation
Are Breast-fed Infants More Resilient? Feeding Method and Cortisol in Infants