The Gut‒Breast Axis: Programming Health for Life

Abstract

The gut is a pivotal organ in health and disease. The events that take place in the gut during early life contribute to the programming, shaping and tuning of distant organs, having lifelong consequences. In this context, the maternal gut plays a quintessence in programming the mammary gland to face the nutritional, microbiological, immunological, and neuroendocrine requirements of the growing infant. Subsequently, human colostrum and milk provides the infant with an impressive array of nutrients and bioactive components, including microbes, immune cells, and stem cells. Therefore, the axis linking the maternal gut, the breast, and the infant gut seems crucial for a correct infant growth and development. The aim of this article is not to perform a systematic review of the human milk components but to provide an insight of their extremely complex interactions, which render human milk a unique functional food and explain why this biological fluid still truly remains as a scientific enigma.

Keywords: entero-mammary pathway; gut colonization; gut‒breast axis; human milk; immunomodulation; tolerance.

Figure 1

Schematic representation of the complex interactions between maternal gut, milk, and infant gut and their relevance for infant growth, development, and health.

Figure 2

Complementarity between the maternal gut, the breast, and the infant gut, illustrating the synthesis, transfer, use, and/or absorption of some of the components of human milk. AA: amino acids; EVs: extracellular vesicles; FA: fatty acids; HMOs: human milk oligosaccharides; LCFA: long chain fatty acids; MAG: monoacylglycerides; RIB: ribosomes; SCFA: short chain fatty acids; TAG: triacylglycerides. Adapted from [18].