Synbiotics: the impact of potential prebiotics inulin, lactulose and lactobionic acid on the survival and growth of lactobacilli probiotics

Prebiotics are increasingly added to probiotic food preparations (synbiotics) to enhance probiotic survival and growth. This study examines the ability of three potential prebiotics; inulin, lactulose and lactobionic acid to support the growth of five probiotic lactobacilli cultures and provide protection from bile acid stress. Three lactobacilli probiotics could not utilise any of the prebiotics, with growth less than 20% compared to growth in glucose. Only Lactobacillus acidophilus NCFM and Lactobacillus reuteri NCIMB 11951 utilised lactulose. Similar variability was observed with the ability of the prebiotics to protect probiotics from bile acid stress. Both L. acidophilus NCFM and L. reuteri NCIMB 11951 were able to grow in 2 mM cholic and taurocholic acid when incubated in synbiotic combinations with lactulose (1%) or lactobionic acid (1%). Although synbiotic preparations are increasingly used, the potential benefits to gut health may be limited as only specific combinations may enhance probiotic survival and growth.