Hormones In Breast Milk Research Articles

Breast Milk Hormones and Regulation of Glucose Homeostasis

Growing evidence suggests that a complex relationship exists between the central nervous system and peripheral organs involved in energy homeostasis. It consists in the balance between food intake and energy expenditure and includes the regulation of nutrient levels in storage organs, as well as in blood, in particular blood glucose. Therefore, food intake, energy expenditure, and glucose homeostasis are strictly connected to each other. Several hormones, such as leptin, adiponectin, resistin, and ghrelin, are involved in this complex regulation. These hormones play a role in the regulation of glucose metabolism and are involved in the development of obesity, diabetes, and metabolic syndrome. Recently, their presence in breast milk has been detected, suggesting that they may be involved in the regulation of growth in early infancy and could influence the programming of energy balance later in life. This paper focuses on hormones present in breast milk and their role in glucose homeostasis.

Duration of Breast-feeding and Adiposity in Adult Life

Few studies have examined whether the duration of breast-feeding is associated with BMI in adult life. In the past, the heights and weights of infants and the duration of breast-feeding were routinely recorded at infant welfare clinics in Helsinki, Finland. Most infants in the city were taken to these free clinics. The Helsinki Birth Cohort comprises 13,345 people born in the city during 1934-1944; 84% were breast-fed. In 2001, a questionnaire was sent to members of the cohort asking about their weight and height. A random sample of 2003 men and women attended a clinic at which height, weight, and body composition were measured. We studied sibships that included 2 or more people from the cohort. There were 1823 subjects: 831 had completed the questionnaire; 129 had attended the clinic. We grouped the subjects according to duration of breast-feeding: 0-2 mo, 3-4 mo, 5-7 mo, and 8 mo or more. We compared siblings who were discordant for duration of breast-feeding. We found that a longer period of breast-feeding was associated with lower BMI at 1 y of age (P = 0.04 for a linear trend). This relation disappeared by the age of 7 y. People breast-fed for 5-7 mo had the lowest reported BMI at age 60 y, although this was not statistically significant; 8.8% more people breast-fed for 8 mo or more had reported BMIs that were overweight (25 to 30 kg/m(2)) compared with those breast-fed for shorter periods (P = 0.06). Breast-feeding for <2 mo or 8 mo or more was associated with an increased BMI and percentage body fat in later life, measured at the clinic (P = 0.08 and P = 0.03 for quadratic trends). We conclude that breast-feeding for <2 mo may be deleterious, possibly because of lack of exposure to protective factors in breast milk. Breast-feeding beyond 8 mo may be deleterious because mother's hormones in breast milk reset the infant's hypothalamic-pituitary-thyroid axis.

Breast Milk Hormones and Their Protective Effect on Obesity

Data accumulated over recent years have significantly advanced our understanding of growth factors, cytokines, and hormones in breast milk. Here we deal with leptin, adiponectin, IGF-I, ghrelin, and the more recently discovered hormones, obestatin, and resistin, which are present in breast milk and involved in food intake regulation and energy balance. Little is known about these compounds in infant milk formulas. Nutrition in infancy has been implicated in the long-term tendency to obesity, and a longer duration of breastfeeding appears to protect against its development. Diet-related differences in serum leptin and ghrelin values in infancy might explain anthropometric differences and differences in dietary habits between breast-fed and formula-fed infants also later in life. However, there are still gaps in our understanding of how hormones present in breast milk affect children. Here we examine the data related to hormones contained in mother's milk and their potential protective effect on subsequent obesity.

Gastrointestinal peptides and the adaptation to extrauterine nutrition.

The adaptation to extrauterine nutrition involves complex physiological changes at birth which may be regulated by genetic endowment; enteral nutrients, secretions, and bacteria; and endogenous hormones and exogenous hormones in breast milk. The hypothesis is explored that enteral feeding after birth may trigger key adaptations in the gut and in metabolism partly through the mediation of gastrointestinal hormone secretion. Gut peptides are found in the early human fetal gut and by the second trimester some are found in high concentrations in the fetal circulation and amniotic fluid. Major plasma hormonal surges occur during the neonatal period in term and preterm infants: notably in enteroglucagon, gastrin, motilin, neurotensin, gastrointestinal peptide, and pancreatic polypeptide. These events do not occur in neonates deprived of enteral feeding. A progressive development of dynamic gut hormonal responses to feeding is observed. The pattern of gut endocrine changes after birth is influenced by the type and route of feeding. Potential pathophysiological effects of depriving high risk neonates of enteral feeding are considered. It is speculated that infants committed to prolonged total parenteral nutrition from birth may benefit from the biological effects of intraluminal nutrients used in subnutritional quantities.

1439 ABNORMALLY PROLONGED CAFFEINE ELIMINATION IN BREAST FED INFANTS

Four exclusively breast fed infants (BFI) on caffeine (C) maintenance therapy for apnea of prematurity have been followed for a 5 month period with serial blood C dosage (pre and post-dose) allowing calculation of C t½. BFI were compared to 14 formula fed infants (FFI). Contrary to FFI who presented a sharp increase in C elimination with post-conceptional age, C t½ decreased very slowly in BFI. This is expressed by some of our data at different post-conceptional age in BFI and FFI with respectively at 39-42 wks: 83.7 h (99.5-71.5) vs 61.7 h (100-26.8); at 47-50 wks: 74.7 h (90.0-58.7) vs 30 h (63-11.2); at 55-58 wks: 51.2 h (58-44.4) vs 11.8 (30-1). One BFI did not show any maturation with a steep decrease of C elimination from 80 h at 40 wks to 102 h at 44 wks and 372 h at 54 wks.Mean pre-dose was 4 times higher in the BF group at 51-54 wks: 11.5 mg (16.1-8.3) vs 2.8 ± 2.6 mg, and 6 times higher at 55-58 wks: 7 mg (7.4-6.4) vs 1.1 ± 1.1 mg. These data have serious therapeutic implications and confirm that monitoring C is mandatory, particularly in BFI who can show abnormal C accumulation.These data show a progressive discrepancy with post-conceptional age in caffeine elimination between BFI and FFI strongly suggesting that maternal hormones in breast milk repress or inhibit the normal maturation of C elimination.

Serum Thyroxine Values in Breast-fed Infants-Reply

In Reply .—It was precisely because of the arguments cited by Dr Banagale that my co-workers and I chose to study healthy, term infants at 2 to 3 weeks of age. Analysis of thyroid hormones in breast milk is beset with many problems; premature infants frequently have low serum T 4 values. Finally, any effect of nursing should be more evident after nursing is well established. The results of recent studies performed by my colleagues and me in collaboration with the Texas Department of Health, support Dr Banagale's contention that the method of feeding does not impair the accuracy of neonatal screening programs for primary congenital hypothyroidism. The mean filter paper spot-test T 4 value of breast-fed infants is marginally higher than that of formula-fed infants, aged 2 to 3 weeks old. However, the overlap of values is so great that the difference is not clinically important. Therefore, we conclude