Microbiome Bites Feb 20th: Oral Prebiotics, Sleeplessness and the Gut-Brain Axis
1. Prebiotics for the Oral Microbiome
Prebiotics are an excellent way to promote a healthy microbiome. There are a number of prebiotics on the market for the gut microbiome, but little is known about prebiotics that support healthy oral (mouth) bacteria. So far arginine seems to be the only oral prebiotic with any scientific evidence supporting its benefits (you can read more here).
In a study published in the Journal of Clinical Periodontology this week, scientists show that nutritional stimulation by prebiotics could be used to balance the oral microbiome. The team identified two compounds that show promise as oral prebiotics:
The compounds selectively favored beneficial oral bacteria and helped them out-compete bad bacteria in test tube experiments.
2. The Gut Microbiome is Not Affected by Short-Term Sleep Restriction
It is widely believed that there is a relationship between sleep and the gut microbiome because both sleep restriction and gut microbiome dysbiosis are associated with metabolic diseases such as obesity and diabetes.
In a study published in the journal PNAS, scientists set out to explore the relationship between the two from the hypothesis that lack of sleep may upset the gut microbiome and cause metabolic diseases.
By studying both rats and humans, the team found no obvious changes in the gut microbiome in response to a short-term lack of sleep. So the search continues.
The study is here.
3. The Gut Microbiome is Controlled by the Enteric Nervous System
Maintaining a balanced gut microbiome is critical for intestinal health and the prevention of chronic inflammation. Every few minutes the gut environment is disrupted by peristalsis (the waves of contraction that help move food through your system), under the control of the enteric nervous system. This led scientists to question whether the bacteria present in the gut microbiome are specifically adapted to such a physically dynamic environment.
To address the question, scientists used a zebrafish model that lacks an enteric nervous system, thus lacking peristalsis. They found that the lack of an enteric nervous system was associated with high levels of inflammation in some fish. Profiling these fish revealed an overabundance of pro-inflammatory bacteria in their gut microbiomes. Transplanting these bacteria into healthy fish caused the same inflammation. Conversely, transplanting anti-inflammatory bacteria into the fish lacking an enteric nervous system could rid them of the inflammation. The researchers therefore conclude that the enteric nervous system is very important in regulating which bacteria are present in the gut microbiome.
You can read the study here.