The concept of probiotics has evolved immensely since it was first proposed a century ago. There are numerous potential health benefits attributed to probiotic bacteria, from preventing gastrointestinal (GI) infections to stimulating the immune system. Recent evidence is now quite compelling for a role of probiotics in enhancing liver health. Liver injury is on the rise worldwide with nonalcohol fatty liver disease (NAFLD) the fastest rising liver problem, due largely to the rise in obesity and type II diabetes. A damaged liver can progress to more serious conditions such as steatohepatitis and cirrhosis, and the intestinal microflora are believed to play a large role in this progression. When the intestinal microbial flora is high in facultative microbes, particularly the Enterobacteriaceae, and low in anaerobes such as bifidobacteria, higher levels of ammonia, endotoxins and other compounds enter the blood stream. This results in direct liver damage and also indirectly from pro-inflammatory cytokines such as TNF-α. Probiotics have been shown to modulate the intestinal microflora and decrease the urease producing gram negatives and increase the anaerobic population. While results have been obtained with current probiotic strains, more effective strains could be obtained if all the characteristics bacteria use to survive and compete successfully in the intestine were known. The genomics era is now providing the tools to more effectively understand probiotic interactions in the intestine. This will lead to a new generation of exciting probiotics in the future.
- Liver health