Myo-inositol found in breast milk may enhance neuronal connectivity in brain of infants

Breast feeding is long known for its ideal nutrition for infants. It has a nearly perfect mix of vitamins, protein, and fat that baby needs to grow. Breast milk contains antibodies that help baby build a better immune system. Breastfeeding is also said to lower baby's risk of having asthma or allergies. Breastfeeding has been linked to higher IQ scores in later childhood in some studies.

The present study in PNAS Journal reveals substantial benefits of the human milk component myo-inositol for developing synapses across species, including in human neurons. The findings demonstrated that myo-inositol promotes neuronal connectivity and can guide dietary recommendations across life stages.

This is a significant finding for pediatric nutrition and the improvement of infant formulas in under resourced areas with conditions that prevent sufficient breastfeeding. Moreover, this carbocyclic sugar can promote synapse density in mature brain tissue.

The researchers aimed to know the effects of micronutrients on brain connectivity. The researchers studied samples from three geographically diverse locations because they hypothesized that the micronutrients present across all samples—independent of diet, race, and location—may be of biological significance. They were especially interested in components that changed over the course of lactation in the same way.

The key findings of the study are

• The researchers determined that Myo-inositol is most abundant in human milk during early lactation when neuronal connections rapidly form in the infant brain.

• Myo-inositol promoted synapse abundance in human excitatory neurons as well as cultured rat neurons and acted in a dose-dependent manner.

• Mechanistically, myo-inositol enhanced the ability of neurons to respond to transsynaptic interactions that induce synapses.

• Effects of myo-inositol in the developing brain were tested in mice, and its dietary supplementation enlarged excitatory postsynaptic sites in the maturing cortex.

• Utilizing an organotypic slice culture system, they additionally determined that myo-inositol is bioactive in mature brain tissue, and treatment of organotypic slices with this carbocyclic sugar increased the number and size of postsynaptic specializations and excitatory synapse density.

Researchers concluded that “This study advances our understanding of the impact of human milk on the infant brain and identifies myo-inositol as a breast milk component that promotes the formation of neuronal connections.”

Reference: Dhrubajyoti Chowdhury, Ilona Kondratiuk, Beau Labhart et al; The human milk component myo-inositol promotes neuronal connectivity, PNAS Journal Article, 2023 vol 30; DOI: 10.1073/pnas.2221413120.