The benefits of eating fish during pregnancy

Everyone knows that maternal diet during pregnancy significantly influences the health of the future infant. Less well-known is that the consumption of fish directly modulates the maternal gut microbiota.


Reduced risk of premature birth, improvement of maternal mood, better development of the brain, vision, motor skills, heart and immune system in newborns: the consumption of omega-3 oils (naturally present in salmon, mackerel, eggs, spinach, avocado and more) is favorable to the health of both mothers and their babies! This is why health authorities recommend that pregnant women consume between two and three portions of fish per week. This upper limit is fixed because of the risks associated with ingestion of mercury, found in varying quantities in fish. What is the impact of this dietary recommendation on the gut microbiota of newborns?

A microbiota affected by the maternal diet

To find out, a team of researchers analyzed stool samples from around one hundred babies aged around 4 months on average. Their results revealed three gut microbiota profiles: one dominated by bifidobacteria–also the richest and most diverse, one dominated by Escherichia spp., and the last by another specific bacterium, i.e. Enterobacter. Infants whose mother followed the dietary recommendations during the third trimester (at least 2 portions of fish per week) were up to 5 times more likely to have a microbiota dominated by bifidobacteria than by Escherichia. Could this protect them against certain diseases? It is possible, according to certain studies indicating that a microbiota with a low content of bifidobacteria is associated with irritable bowel syndrome, inflammatory bowel disease, celiac disease, and more.

Validity of the dietary recommendations

The authors consider that this study confirms the validity of dietary recommendations regarding consumption of fish during the third trimester of pregnancy–a critical period for brain development–revealing a benefit unknown until now. According to the authors, understanding the impact of the maternal diet on the infant gut microbiota should help better define the dietary recommendations for pregnant women.



Simione Meg et al. Maternal fish consumption in pregnancy is associated with a Bifidobacterium-dominant microbiome profile in infants. Curr Devs Nutr. 2019 Dec 19; 4 (1), nzz133. ; doi: 10.1093/cdn/nzz133