I do use an enzyme product with ingredients similar to probiotic products (Fermentation products of various probiotic bacteria.) I can see that it does work, but when I look at the history of probitoics, the science seems odd to me.

History:
Lactobacillus delbrueckii subspecies bulgaricus was isolated from yogurt in 1905 by doctor Stamen Grigorov. Dr. Grigorov did much work to show that the yogurt was benificial to health.

Ilya Ilyich Mechnikov proposed that the bacteria were benificial because they replaced the less benign bacteria in the gut, but also thought that lactic acid alone was beneficial, and drank sour milk regularly.

Minoru Shirota then took up the cause of probiotics. The origional strains studied by Grigorov and Mechnikov were shown to not survive the trip to the gut.

Here's the sticky turning point in the history of probiotics: Shirota realized the previously isolated bacteria were not surviving to reach the gut, and instead of reconsidring Mechnikov's theory of how probiotics worked, he threw out Grigorov's results and started fresh with a new strain of bacteria he isolated in 1930 that does survive to the gut. Most probiotic research since has been done with strains that survive to reach the gut.

http://en.wikipedia.org/wiki/Lactobacillus_bulgaricus
http://en.wikipedia.org/wiki/Stamen_Grigorov
http://en.wikipedia.org/wiki/Eli_Metchnikoff
http://en.wikipedia.org/wiki/Minoru_Shirota

Today
So why is the modern probiotic enthusaist convinced that live bacteria reaching the gut is the method of action? It could be the bacteria, could be the enzymes, could be the lactic acid, or some other compound that is a result of fermentation? (Zocor, as an example, is a drug derived from a fermentation product. http://en.wikipedia.org/wiki/Simvastatin)

I've not seen anywhere research conducted on why probiotics work, nor comparing one strain to another. All the research I've seen just compares a single strain to a placebo, and they all have basically the same results, of calming troubled guts and reducing bad bacteria in the gut.

 Quote: Denise Skidmore

I do use an enzyme product with ingredients similar to probiotic products (Fermentation products of various probiotic bacteria.) I can see that it does work, but when I look at the history of probitoics, the science seems odd to me. .... Most probiotic research since has been done with strains that survive to reach the gut. ... I've not seen anywhere research conducted on why probiotics work, nor comparing one strain to another. All the research I've seen just compares a single strain to a placebo, and they all have basically the same results, of calming troubled guts and reducing bad bacteria in the gut.

Yes, food scientists have accepted some concepts underlying the use of probiotics/prebiotics kind of un-discerningly. If that's a word. Microbiologists are less willingly accepting.

I think that research in this decade into microencapsulation (and other delivery systems) changes the field making up the microbes that survive to the gut, but that doesn't throw light on anecdotal evidence of benefits of strains that appear not to survive to the gut unaided, and it will be interesting to watch research into whether they do indeed survive in some instances in some individuals.

When this comes out in two months, if I can understand more than a few words, I'll post back.
http://www.amazon.com/Lactobacillus-Molecular-Biology-Genomics-Probiotics/dp/1904455417/ref=sr_1_1?ie=UTF8&s=books&qid=1225295794&sr=1-1

Thanks for the Wikipedia citations; I will definitely check them out.

Have you read any of Gary Huffnagle's research? His 2007 book (recommended to me by Mike Armstrong) is fascinating, and pretty reticent about extravagant claims.

It's a very interesting field.

 Quote: Connie Sutherland

Have you read any of Gary Huffnagle's research?

Not that I remember. I'm horrible about keeping track of my sources. Most of the research available free on the net is just the abstracts of the papers. This is usually good enough for me, as it gives the type of research done and basic conclusions.