A narrative review of the associations between six bioactive components in breast milk and infant adiposity

Abstract

Objective This narrative review examines six important non-nutritive substances in breastmilk, many of which were thought to have little to no biological significance. The overall objective of this narrative review is to provide background on key bioactive factors in breastmilk believed to have an effect on infant outcomes (growth and body composition). Methods The evidence for the effects of the following six bioactive compounds in breastmilk on infant growth outcomes are reviewed: insulin, leptin, adiponectin, ghrelin, interleukin-6 (IL-6) and tumor necrosis factor α (TNF-α). Results The existing literature on the effects of breastmilk insulin, ghrelin, IL-6 and TNF-α and their associations with infant growth and adiposity is sparse. Of the bioactive compounds reviewed, leptin and adiponectin are the most researched. Data reveals that breastmilk adiponectin has negative associations with growth in infancy. Conclusions There is a need for innovative, well-designed studies to improve causal inference and advance our understanding in the effects of breastmilk and its components on offspring growth and body composition. The recommendations provided, along with careful consideration of both known and unknown factors that affect breastmilk composition, will help improve, standardize and ultimately advance this emergent field.

Associations of Maternal Weight Status Before, During, and After Pregnancy with Inflammatory Markers in Breast Milk

“…14,15 There is abundant evidence that many non-nutritive factors found in breast milk can remain bioactive in the infant. 16 The presence of protease inhibitors in milk, 17,18 the immaturity of the infant gut and high gut pH that favors absorption of bioactive compounds, [18][19][20] and the existence of gut receptors for numerous milk hormones and cytokines, 21,22 all support the notion that proteins in breast milk remain bioactive.…”

Human milk: composition and health benefits

“…Particularly, leptin milk concentration has been found to be directly correlated with maternal body mass index. 37,38 Breastfeeding and associated outcomes Advances in research have clearly indicated that human milk offers both optimal nutrient supply and bioactive compounds that contribute to the short and long-term health benefits associated with breastfeeding. Remarkably, many health outcomes have been reported to be directly correlated with the duration of breastfeeding, suggesting a potential cumulative effect.…”

TOS Scientific Position Statement: Breastfeeding and Obesity

“…Because information on duration and intensity of breastfeeding is not always reported, it is unclear if there is an optimal duration and/or intensity of breastfeeding that is necessary to confer a reduced risk in offspring adiposity. Furthermore, differences in overweight/obesity risk in breastfed versus non‐breastfed infants are also likely influenced by differences in parental feeding styles , patterns of feeding self‐regulation , maternal sociodemographic factors such as race/ethnicity and education, and maternal health (e.g., adiposity, inflammation, insulin resistance) that have been seldom reported or controlled for in published studies . Breast milk is a dynamic, nonuniform substance, and aside from its nutritional properties, breast milk comprises multiple compounds including growth factors, cytokines, immunoglobulins, metabolic hormones, oligosaccharides, and microbiota.…”