A recent study sheds light on the complex relationships between gut microbiota, plasma lipids, and brain activity, linking these interconnected pathways to cognitive deficits associated with moderate acute malnutrition (MAM) observed in children.
Globally, malnutrition affects over 30 million children each year, significantly impacting their immediate health and long-term cognitive development. Survivors of MAM often experience lasting neurocognitive consequences, diminishing their academic performance and socioeconomic prospects. Despite the gravity of these issues, the precise mechanistic pathways through which malnutrition induces cognitive impairment have remained largely obscure.
This research was conducted primarily among children aged 12 months old from the densely populated Mirpur region of Dhaka, Bangladesh, which has one of the highest rates of childhood malnutrition worldwide. The study population included 159 children diagnosed with MAM and 75 well-nourished controls, carefully selected from community surveys over the course of 2022.
The primary objective of the study was to assess how MAM influences children's gut microbiome composition, plasma lipid profiles, brain activities, and cognitive outcomes. Utilizing multi-system SHAP interpreted random forest models and co-abundance network analyses, researchers unveiled significant alterations linked to nutritional status.
Among the noteworthy discoveries, children suffering from MAM exhibited pronounced differences in their faecal microbiome, particularly with increased levels of certain bacteria—specifically, Rothia mucilaginosa and Streptococcus salivarius. These changes correlated with depleted levels of beneficial bacteria, such as Bacteroides fragilis, typically associated with improved gut health and cognitive function.
Notably, the faecal microbiome alterations were accompanied by altered plasma lipid profiles. MAM children showed significant changes characterized by lower levels of odd-chain fatty acids and ceramides, which are integral to neurological development. According to the study, “MAM was associated with major changes to the plasma lipidome... including those known to be specific to neurological development and function.”
To assess brain activity, resting-state electroencephalography (EEG) was performed on participants, which revealed significant discrepancies between MAM-infected children and those who were well-nourished. The EEG data demonstrated altered power spectral density (PSD) patterns, particularly within the beta and gamma frequency bands, which are reflective of cognitive functions such as concentration, alertness, and mental acuity. Overall, malnourished children showed reduced activity across these bands, hinting at potential deficits in mental processes related to their nutritional status.
The evaluations also included cognitive assessments using the Bayley Scales of Infant and Toddler Development. Results indicated stark reductions across various scores for children with MAM, particularly noted deficits in expressive communication and fine and gross motor skills. The findings echoed the statement, “These findings support the hypothesis... delay gut microbiome and brain development.”
Through the comprehensive analyses of faecal samples, plasma lipids, and EEG data, the researchers paved the way for enhanced intervention strategies targeting the interconnected pathways of gut microbiota and cognitive outcomes. The work presents the foundation for future research aimed at directly addressing these malnutrition-related cognitive impairments, as the present study’s authors concluded, "Although causal links require empirical validation, this study provides insights to improve interventions targeting MAM-associated neurodevelopmental deficits."
One of the key revelations from the study was the implication of Bacteroides fragilis as potentially protective against impairments associated with malnutrition due to its role in synthesizing important brain-supportive lipids. Future exploration aimed at reinforcing gut health through dietary or microbial interventions may open new avenues for enhancing cognitive development among malnourished children.
Collectively, the study's integrated approach emphasizes the necessity for continued investigations to unravel the complex interplay between nutrition, microbiome health, and brain performance, particularly as it relates to vulnerable populations globally, including children living with malnutrition.