A breast milk exclusive diet promotes dysbiosis in the gut microbiome of six-month-old anemic infants

Abstract

Iron deficiency is the most common nutritional deficiency worldwide, with recent studies reporting the prevalence of iron deficiency anemia being 19% in Canada alone. The microbiome is increasingly recognized as a key regulator of immunity, and imbalances have been linked to a range of diseases. As a result, there is great interest in understanding the association between the microbiota and the onset of anemia. While there have been steady improvements in this regard, the impact of various types of diets on the gut microbiota in the context of anemia is not well-established. Since diet significantly affects the microbiota composition, we investigated effects of breast milk exclusive diet versus a complete diet on microbiota composition in anemic and normal infants. We found significant differences in alpha and beta diversity across diets among anemic six-month-old infants, but not in normal infants. In addition, our core microbiome analyses revealed certain genera that were unaffected by diet or anemic status, while others were characteristic of the anemic groups, such as Actinomyces and Bacteroides. Lastly, we observed decreased abundance of several key commensal genera in breast milk fed infants as compared to those fed a complete diet, along with an upregulation of enzymes associated with hemoglobin synthesis and iron scavenging. Overall, our study provides fundamental understanding into how diet affects the gut microbiota of anemic infants.