The gut microbiome is the community of bacteria and other microbes living in the digestive tract. It has become one of the busiest areas of health research, and it has also attracted a great deal of marketing that runs far ahead of the evidence. Light therapy is a good example.
What the research shows
A small number of animal studies, mainly in mice, have reported that near-infrared light applied to the abdomen was followed by changes in the make-up of gut bacteria. The researchers suggested the light may act on the body as a whole rather than on the bacteria directly.
That is an interesting early finding. It is not evidence that light therapy improves gut health in people.
What we do not know
- Whether the same effect happens in humans at all
- Whether any change in bacteria would be good, bad or neutral for health
- Which wavelength, dose or session length would matter
There are no controlled human trials showing that red or near-infrared light improves digestion or any digestive condition.
When to see a doctor
Ongoing digestive symptoms, such as changes in bowel habit, blood in the stool, unexplained weight loss, persistent pain or bloating, need medical assessment. Diet, sleep, physical activity and, where needed, medical treatment are what the evidence supports for gut health.
Related reading
See our pages on inflammation and immune response.
