Since that conference I have read quite a bit on gut bugs, more correctly known as the gastrointestinal microbiome. Overall, we have ten times more bacteria in our bodies that we have actual cells, and a hefty chunk of those are in our lower intestines. So what difference would adding a few more possibly make?
Well, aside from the assertions regarding internal effects, a new paper has suggested probiotics may have a more visible benefit that may even confer an evolutionary benefit. Researchers from Greece, Canada and MIT in the US, noticed that the fur of mice being fed probiotic yoghurt for studies on intestinal effects became unusually lustrous as the experiments progressed. They followed up with a separate study on the effects of the probiotic yoghurt on the fur and indeed found daily consumption of the yoghurt with the probiotic microorganism Lacotobacillu reuteri (L. reuteri) resulted in thicker skin and more lustrous fur, that was in part related to an effect on the immune system. To be sure it wasn't the yoghurt itself that was responsible, in a separate group of mice the investigators supplemented the diet with the L. reuteri bug in drinking and found the same effect. What's more, they also found increased acidity in the mucous membranes of the animals which they associated with increased fertility. The investigators thus concluded that the 'healthful glow' imparted on the animals from eating the probiotic yoghurt ( or drinking the 'good bug' in water) was an external display of fertility. Studies in humans are sure to follow, faster than you can say Activia. In the meantime, I am off to see what's in the 'fridge....
Levkovich et al. Probiotic Bacteria Induce a ‘Glow of Health’. PLoS One. 2013; 8(1): e53867.Published online 2013 January 16. doi: 10.1371/journal.pone.0053867