Photobiomodulation (PBM) significantly altered the microbial diversity of the microbiome, an effect most pronounced in mice treated three times per week with Near Infrared light (808 nm)
PBM produced a 10,000-fold increase in the proportion of the beneficial bacterium Allobaculum in the microbiota of mice after 14 days of treatment.
Preliminary research (unpublished) indicates a similar beneficial response in humans including increases in 3 beneficial bacterial species and decreases in the Firmicutes:Bacteroides ratio, a ratio proposed as an indicator of gut health.
"It is now recognized that a healthy gut microbiome is to a large extent responsible for a healthy individual.
Changes in the health status of humans and model organisms are accompanied by changes in the gut #microbiome."
Side note: In this Journal, the authors note the deleterious effects of ultraviolet light on the microbiome, but this may not be the case.
As of recently, Narrowband #Ultraviolet light shows beneficial modulation of microbiome in humans.