Calcium carbonate alleviates calcium deficiency through changes in the gut microbiota and metabolites

The use of non-drug intervention for calcium deficiency has attracted attention in recent years. Although calcium carbonate is the preferred raw material for calcium supplements, the mechanism of its anti-calcium deficiency effect from the perspective of intestinal flora and metabolomics is rarely reported. In this study, we compare the abundance of intestinal flora and the expression levels of fecal and plasma metabolites in control rats fed with basic diet, low calcium fed rats, and calcium carbonate treated rats. The results revealed that compared with low-calcium rat, calcium content and bone mineral density of the midpoint and distal femur of rats in the oral calcium carbonate group were significantly improved. 16S rRNA sequencing and metabonomics analysis showed that calcium carbonate intervention altered the composition of intestinal microbiota and metabolic profiles in feces and plasma of low-calcium fed rats. Further, correlation analysis showed that selected intestinal flora were significantly correlated with metabolites enriched in feces and plasma. In conclusion, calcium carbonate intervention has the potential to reduce calcium deficiency and related symptoms, while affecting intestinal microbiota composition and metabolic characteristics in low-calcium rats. This study highlights scientific evidence for the potential effect of calcium carbonate as a calcium supplement on calcium deficiency.