Dead Probiotics still work!
Yes it is sort of hard to believe dead bacteria still had the same benefits as live ones. However an associate of mine gave me a good idea why this could be. Humans have been living with dead bacteria for thousands of years. They are in our gut , on our skin and all around us so in it makes sense our bodies would recognise and react to dead bacteria.
The study in this post (see abstract below) reinforces the reported health benefits from using shelf-stable probiotics that are not live cultures. Shelf-stable probiotics work as well as live probiotics. It could be that the strain of bacteria is more important than whether the bacteria is alive and there are certainly plenty of studies on the effects of particular bacteria strains. As it stands more and more people are using shelf-stable probiotics probably because they keep for a very long time and you can take them with you when you travel.
Here’s the study
The probiotic paradox: live and dead cells are biological response modifiers
Probiotics are usually defined as products which contain viable non-pathogenic micro-organisms able to confer health benefits to the host. There are specific gastrointestinal effects of probiotics such as alleviating inflammatory bowel disease, reducing acute diarrhoea in children, inhibiting Salmonella and Helicobacter pylori, removing cholesterol, secreting enzymes and bacteriocins and immunomodulation. However, many of the effects obtained from viable cells of probiotics are also obtained from populations of dead cells. Heat-killed cells of Enterococcus faecalis stimulate the gastrointestinal immune system in chicks. Dead bifidobacteria induce significant increases in TNF-alpha production. Administration of heat-killed E. faecalis to healthy dogs increases neutrophil phagocytes. The probiotic paradox is that both live and dead cells in probiotic products can generate beneficial biological responses. The action of probiotics could be a dual one. Live probiotic cells influence both the gastrointestinal microflora and the immune response whilst the components of dead cells exert an anti-inflammatory response in the gastrointestinal tract. This is quite analogous to a proposed mode of action of antimicrobial growth promoters in animal production. This has several implications for the production and application of probiotics, as it will be difficult to assess the relative proportions of live and dead cells in a probiotic culture. Variable amounts of dead cells might contribute to the variation in response often seen with live probiotic cultures. However, the use of dead probiotics as biological response modifiers has several attractive advantages; such products would be very safe and have a long shelf-life.