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A mother’s diet during pregnancy may alter the microbiome of her baby’s gut, suggests a new observational study which noted that this effect also seems to vary depending on whether the baby was delivered vaginally or via caesarean section.





Authors of the paper, published in Microbiome, suggest that the finding may have implications for the dietary recommendations given to pregnant and lactating women.





Previous findings have shown that method of delivery has impact on the microbiome of infants, and that a high-fat diet could have influence on microbial composition, but investigation of how maternal diet affects offspring microbiome has been limited.





The study, led by Sara Lundgren of the Department of Epidemiology, Geisel School of Medicine at Dartmouth, used a sample cohort taken from the New Hampshire Birth Cohort Study. The authors collected 145 stool samples from infants with maternal diet was assessed using a questionnaire.





The analysis showed that bacteria in the infant gut at 6 weeks post-delivery is organized into clusters of bacterial composition which differ depending on the birth delivery method, as was expected.





Diet had a range of effects on this microbiome. Some of the key findings the authors highlighted were that maternal dairy intake was associated with a higher likelihood of infants born by caesarean section having a high clostridium count. Babies delivered in this fashion have a higher risk of dairy allergies than those born vaginally. They also report that a maternal diet involving fish and seafood was associated with higher Streptococcus levels in the gut. Bacteria from this genus are known to have infected farmed fish populations. Surprisingly, levels of Bifidobacterium, generally considered beneficial bacteria, decreased in association with increasing maternal fruit consumption, although increased with a red or processed meat diet.





Lead author Lundgren, speaking to Biomed Central, said “Our study demonstrates an association of a readily modifiable factor, maternal diet, with the infant gut microbiome. This knowledge may be key for developing evidence-based dietary recommendations for pregnant and lactating women.”





As an observational study, this research doesn’t mean we can definitely conclude that maternal diet alone directly caused these changes. The effect that diet may have on breast milk may be a confounding factor, and the researchers didn’t have the ability to compare breast-fed babies with formula-fed babies. Nonetheless, the study will be a jumping-off point for research which investigates the relationship between breast milk, maternal diet, and infant gut bacteria, which will hopefully result in healthier babies with better gut bacteria.