On intestinal barrier dysfunction as a conserved late-life state in ageing

In their Article "Short lifespan under dietary cholesterol depletion is associated with increased intestinal permeability in female Drosophila" (s41514-026-00341-5), Zanco and coauthors investigate how dietary cholesterol limitation affects intestinal barrier function, Smurf phenotype occurrence, and lifespan in female Drosophila melanogaster. They find that restriction of diet cholesterol decreases the lifespan of mated female flies and is associated with an augmented Smurf Increase Rate. They conclude from these findings that "intestinal barrier dysfunction is unlikely to be a universally conserved mechanism of ageing-related mortality." I contend that this conclusion not only is inconsistent with previously published experimental and theoretical work on Smurfness, intestinal permeability, and two-phase models of ageing in Drosophila, nematodes, zebrafish and mice, but is not even supported by the data they present.