Correlation, not causation. With 500-1000 identified/unidentified species of gut bacteria floating around, mimicking one is a bad data set. Corollary example,

Correlation, not causation. With 500-1000 identified/unidentified species of gut bacteria floating around, mimicking one is a bad data set. Corollary example, we've not proved that H.Pylori causes Ulcerative Colitis, yet they coexist frequently.