Long-term influence of maternal dietary omega-3 on their offspring metabolism
Gut microbiota is a complex biosystem that covers the walls of the digestive tract and regulates metabolism, immune response and other key physiological pathways; its composition and function is profoundly influenced by environmental factors such as diet, the form of birth and the use of antibiotics. At birth, the microbiota is established vertically from the mother (after birth, the offspring’s microbiota is very similar to that of the maternal vagina and studies indicate there is in utero exposure to maternal microbes) and alterations to its original structure in the early stages of life could interfere with the host’s metabolism, subsequently increasing the risk of metabolic disorders. Alteration to normal microbiota is often characterised by a relative abundance of pathogenic bacteria, such as Enterobacteriaceae produced by lipopolysaccharides or a reduction in the commensal species that maintain intestinal homeostasis, such as Akkermansia muciniphilia.
A group of American and Irish researchers have studied how maternal dietary n-3 polyunsaturated fatty acids (n-3 PUFAs) affect the microbiota of offspring and the effects this could subsequently have on the latter. To do this, they employed a transgenic murine model, with Fat-1 mice (carriers of the gene that converts n-6 into n-3 and, therefore, eliminates dietary confounding factors). The authors reported that endogenous n-3 PUFA production during gestation and nursing significantly reduced weight gain and metabolic alteration markers in male pups fed on a high-fat diet. However, the maternal FA status did not seem to have a significant effect on weight gain in female pups. The metabolic phenotypes of the male pups seemed to be mediated by restructuring of gut microbiota composition. Lower maternal exposure to n-3 PUFA was associated with a reduction in epsilonprotobacteria, bacterioids and A. muciniphilia, and a greater relative abundance of Clostridia. Microbiota metabolism and composition were more strongly influenced by the maternal FA profile during nursing than in utero. The maternal FA profile seemed to have a lasting effect on the composition and function of the offspring’s microbiota which persisted until adulthood after lifetime on a high-fat diet.
These data suggest weight gain and metabolic dysfunction in adulthood are mediated by maternal FA status via a long-lasting restructuring of the gut microbiota, and this has major implications for understanding the interaction between modern western diets, metabolic health and gut microbioma.