Proc. Natl Acad. Sci. USA doi:10.1073/pnas.1000079107 (2010)

Supermarket dairy shelves are filled with yogurt products containing live cultures of 'probiotic' bacteria — species that live in the human gut and are proposed to deliver health benefits when eaten at high levels. Three probiotic species seem to alter gene expression in the gut lining of volunteers consuming the cultures. The effect was similar to that of drugs for conditions including inflammation and high blood pressure.

Michiel Kleerebezem at NIZO Food Research in Ede, the Netherlands, and his co-workers analysed the gene-expression profiles of tissue taken from the small intestinal inner lining of seven healthy volunteers who had eaten a placebo and three probiotic cultures — Lactobacillus acidophilus, L. casei and L. rhamnosus — in a random order. The altered gene-expression profiles resembled those associated with the regulation of immune responses, cell growth, metabolism and even wound repair.