Over the past ten years, many studies have been published about how important it is to keep the gut healthy. Generally, that is because commensal bacteria that live in the intestines provide important functions for the benefit of the host, in our case, to us humans. Research has shown that the gut biome forms perinatally and that the most common way to upset the biome is through the ingestion of chemicals in food or the use of antibiotics.
So what does these commensal bacteria do for the host? One of the main function is communicate with the epithelium in the gut to provide upregulation of the Nrf2. As we have described before, the Nrf2 pathway upregulates hundreds of genes that regulate the antioxidant system for protection against xenobiotics. It also regulates functions like mitochondrial biogenesis for ARP or energy synthesis and adipogenesis for fat accumulation. To understand just how the bacteria in the gut communicates to the Nrf2 system a researcher designed a study to show how probiotics do this in mice and flies. Through this study he found:
- Lactobacillus plantarum induces cytoprotection against oxidative stress. Noting that germ-free animals are more susceptible to the effects of Paraquat toxicity. The induction of certain phase 2 genes was probiotic specific.
- Deletion of Nrf2 by inactivating pathway resulted in increased toxicity to Paraquat at levels similar to germ-free animals.
- Animals fed the probiotic, Lactobacillus rhamnosus had enhanced survival and less weight loss when exposed to radiation. The cytoprotective influences were abolished in Nrf2 -/- animals.
- The stressor of reactive species from the activities of the microbes is an example of "hormesis" where the stressor is beneficial to the host, in this case, it activates the Nrf2 system. (1)
1. Lactobacilli Modulate Epithelial Cytoprotection through the Nrf2 Pathway. Cell reports, Vol. 12, No. 8. (25 August 2015), pp. 1217-1225 by Rheinallt M. Jones, Chirayu Desai, Trevor M. Darby, et al.
