A longitudinal study of breastmilk feeding duration, EEG power and early academic skills

The cognitive benefits of breastfeeding are widely recognized; however, its effects on brain development and later academic skills require further examination. This study aimed to examine the longitudinal relations between breastmilk feeding, neurophysiological changes, and early academic skills.

In the Growing Up in Singapore Towards healthy Outcomes (GUSTO) birth cohort, breastmilk feeding practices were collected every 3 months from 3 weeks to 18 months postpartum. Resting electroencephalography (EEG) was recorded at 18 months and power spectral density was derived. The outcomes were a set of early academic assessments administered at age 4 (n = 810). Structural equation modelling was used to investigate EEG power as a mediator between breastmilk duration and early academic skills.

Breastmilk feeding for ≥12 months was associated with better general knowledge, numeracy, and language at age 4 compared to shorter durations of breastmilk feeding (Cohen's d: 1.53-17.44). Linear regression showed that breastmilk duration was negatively and positively associated with low- (i.e., delta, theta) and high-frequency power (i.e., gamma), respectively (Cohen's f²: 0.03-0.09). After adjusting for demographic and child baseline covariates, a decrease in absolute and relative delta, as well as relative theta was associated with better general knowledge and numeracy (Cohen's f²: 0.16-0.25). Relative delta power provided an indirect path between breastmilk duration and early academic skills (x²: 18.390, p = 0.010; CFI: 0.978; TLI: 0.954; RMSEA: 0.040).

Extended breastmilk feeding is associated with reduced low-frequency power and better early academic skills, suggesting benefits to brain development. Additional research to confirm this finding is warranted.