It was positively associated with Hb and RBC counts, negative associated with the tendency for anemia mediated by L-Glutamine and D-Glutamine, negative associated with MCHC mediated by alpha−Santalyl phenylacetate in this study, suggesting that Bacteroides plebeius might help avoid anemia and might be related to immunity. This evidence concerns the gene GSTM1 and anemia (phenotype).