NQO1 and irritable bowel syndrome: However, another study reported that the total relative abundances of azo-reducing bacteria for the majority of individuals (healthy and IBD patients) fell below 3% such that the authors concluded that gut microbiota azoreductases are sparse in both health and disease, a finding that was further supported by the lack of azoreductases in the complementary metatranscriptomics and metaproteomics datasets[26].