Anemia May Mask the Effects that Stunting has on the Dysbiosis of the Infant Gut Microbiota

Abstract

Anemia, the most common nutritional deficiency affecting ~25% of the world’s population, and stunting, defined as hindered growth which impacts an estimated 149 million children under the age of 5 worldwide, have been strongly associated with each other in literature. One connection is through the dysbiosis of the gut microbiome, caused by conditions such as environmental enteropathy, which leads to micronutrient deficiencies, inflammation, and hormonal imbalances that prevent proper growth. The relationship between the infant gut microbiome and the conditions of anemia and stunting has important clinical relevance; however, research examining this relationship is limited. As both anemia and stunting have been found to affect microbiota composition, we investigated the effects of anemia and stunting on infant gut microbiomes. We found that infants with anemia were 2.57 times more likely to be stunted than healthy controls. Our Chao1 alpha diversity analysis revealed significant diversity differences only in the stunted healthy infants, but not in non-stunted healthy, non-stunted anemic, or stunted anemic infants. Stunting was shown to have a larger proportion of unique ASVs compared to anemia based on core microbiome analysis. Likewise, our indicator species analysis identified 22 significant genera indicative of stunting in only healthy infants. Lastly, anemia appeared to reduce the upregulation of differential taxa abundance in stunted infants. Taken together, these results suggest that anemia may conceal the effects of stunting on the infant gut microbiome. Overall, our study provides insight into the complex relationship between anemia, stunting, and the infant gut microbiome.