So, let's talk a little bit about the some of the known applications.

Okay. We have got quite a few products that have shown up on the market that include probiotics, and they are advertised that way. One product that's a big driver right now is the Dannon Yogurt called Activia. It contains a Bifidobacterium animalis strain that has been shown to improve intestinal transit time for people who have slower intestinal transit. That's a very interesting product, with a very specific study that has been done on it with a very specific statement about what the potential benefits are.

Dannon has another product called DanActive, it has a Lactobacillus casei in it. That particular L. casei strain has been studied for the effect on immune function. It's not unique in that regard; many strains have been studied and have shown to have similar effects. But, this particular one is formulated in fermented milk at the levels used in clinical studies, and it has been shown to have some beneficial effects. Other types of applications that are interesting; Kashi has a cereal targeted toward intestinal wellness called Vive. This is a high fiber cereal that includes probiotics. I am not sure if the probiotics are present at high levels, but it's advertised as containing probiotics.

Attune, is a company that just came out with granola bars and candy bars that contain probiotic bacteria. So, that's a whole new way of getting these types of cultures. But, I don't think the Kashi cereal or the Attune bars make any specific claims. They may make statements about overall intestinal health.

It seems like most of what I have read about probiotics suggests that they help with digestive health. Is that fair to say?

Well, I think in many of the statements made on products this is what is said. I like to talk to companies when they make those claims, and ask them, "What studies have you done that show improved digestive health?" They may have done nothing more then showing that it survives intestinal transit, and that you could increase levels of Lactobacillus or Bifidobacterium in your feces. So the question becomes, is your intestinal track better off because of that? I am not really sure if it is or isn't. We don't have a lot of data along those lines.

If you can decrease the pH and increase the short-chain fatty acid levels, that's probably a good thing. But just showing higher numbers of Lactobacillus bacteria is not in itself necessarily beneficial. Sometimes what happens is that companies make claims and make them along those lines. But how rigorous the backing is for some of those claims, I think the company needs to be asked about that.

What kinds of studies have actually been done? But, you are right, I think digestive health tends to be a common claim that is made, and it comes from the idea that you can change the composition of your microflora to increase these potentially beneficial bacteria.

But, the other common claim that's coming out now is improving immune function. There are many studies that have been done that really do document a positive impact on immune function. That's another claim you are going to see more and more. Some of the digestive health, or intestinal health, or intestinal well-being claims come from quite a few studies that have been done, such as clinical studies in the area of prevention or treatment of diarrhea. Of course foods are never going to make a claim like that. Number one, because they are not allowed to. Number two because, they don't really want to be talking about diarrhea on their food products.

What is colonization resistance?

That's another great point when talking about what role our normal colonizing microbes playing in our health. Let me tell you where that concept came from. In the past researchers used what they called germ-free animal colonies. They'd have colonies of mice or rats that were delivered aseptically and raised in a sterile environment so that they did not contain any microbes on them at all. So, they were called germ-free animals. These animals could stay healthy as long as they stayed in a sterile environment.

They could also live as long as their fully colonized counterparts. But, what they found is that if you expose them to any type of either opportunistic pathogen or pathogenic microbes, they were so susceptible to them that they would have very high mortality rates.

In comparison, you could take conventionally colonized animals and you could feed them higher numbers of pathogens and they would be fine.

This phenomenon of being able to resist colonization and infection by these bad bacteria is called colonization resistance. And, it's mediated by our colonizing microbes. So, the explanation is that the microbes that colonize and line our intestinal tract actually provide a barrier to pathogens from gaining a foothold. And, that you need a lot more exposure to these pathogens to actually cause disease.

What about Culturelle?

Culturelle is a dietary supplement sold as a capsule. The Culturelle product has one of the most highly researched probiotic strains in it, which is Lactobacillus rhamnosus GG. Another product that has this strain is the Dannon Danimals product.

L. rhamnosus GG has been well documented to have positive immune system effects. It's been well documented to have a very positive impact on fighting infectious diarrhea, or specifically rotavirus diarrhea in infants and children. There is evidence that shows an impact on antibiotic-associated diarrhea. There are probably over two hundred publications on Lactobacillus rhamnosus GG; it's quite well studied. And, so the Culturelle is a very interesting product from that point of view.

Is the Danimals product beneficial only for children?

They have done studies in both adults and children with the L. rhamnosus GG strain. I would say the data in the studies lean towards infants and children. There is also a very interesting study on the prevention of allergy or atopic dermatitis. That's a very compelling study as well. It just hasn't been repeated by anyone else, and you really do want it confirmed in another lab.

And, another product which I think is also a supplement, Align.

That's a Procter & Gamble product that's been on the market for about a year or so. That particular product has been researched by a group in Ireland that has looked at Irritable Bowel Syndrome symptoms in patients. When that product is in the United States it is not going to say anything about Irritable Bowel Syndrome because it would be considered a drug if it did. But, a study has been done to support that it helps with symptoms of Irritable Bowel Syndrome, which in my opinion is a very interesting target.

And, what about VSL#3?

This particular product contains eight different species of Lactobacillus and Bifidobacterium, and it has been studied by an Italian gastroenterology group. It's shown some very nice response with down regulating inflammation in patients that have Pouchitis. Pouchitis is a condition which arises in patients who have had their colons removed. A pouch is surgically formed so that the fecal contents can collect somewhere, and those pouches are very prone to getting infected and being inflamed.

There is some very nice work published showing that this probiotic blend can actually decrease the recurrence of this inflammation problem in these patients. This is a therapeutic medical use. This finding is interesting because it shows that the impact of probiotics on immune regulation can include improving your ability to fight pathogens or cancers, or, on the flip side, down regulating immune responses.

Okay, so you mentioned before the Lactobacillus rhamnosus GG, what are some of the other most well known probiotics?

Lactobacillus rhamnosus GG is probably the most well known, but there is also another organism: Bifidobacterium lactis Bb12, and that's a microbe that has been studied for use in infant formula. Bifidobacterium lactis HN019 is another strain researched for immune effects. There are also a handful of strains that have been pretty well researched, but are not available in any US product.

Another one would be Lactobacillus reuteri. It is a component in Stonyfield yogurt. This probiotic is interesting since they did a study in Sweden on absences from the work place. They did a placebo control trial, and showed that people who were on the probiotic called in sick less than those not on the probiotic. That's the concept of keeping people healthy.

Right, and of course there is a big economic impact in having fewer sick days.

Another target population for some of these studies has been the daycare population. Can they stay healthy without getting diarrhea or respiratory infections? There are a few limited studies that show that some probiotics can have effects in that regard too.

For the last part of this discussion, what I would like to talk about is future applications, and what's coming.

Oh, I think you are going to see a continued development of both dairy products as well as nondairy applications. I think you are going to see them combined in with prebiotics. Prebiotics are non-digested fibers that seem to feed some of these potentially beneficial microbes. Stonyfield yogurt, for example, does have both Inulin which is a prebiotic, and these other probiotic strains.

Another driver of this field will be the science. If this field is going to remain strong, we need to get more good confirmation of health effects in good independent studies. To date, so much of this research has been funded by industry. And, that's always a potential criticism of the area. There are enough studies done that show effects that I think we are going to start seeing government research being used to substantiate some of these claims in larger studies that are probably even better controlled. I think that's going to be an important development. We are going to know a little bit more about mechanisms as time goes on, how probiotics function, and we are probably going to know more about what specific stains do.

That's one point I haven't made, but it's an important one. It is tempting for people to talk about probiotics in general, but in fact each strain of these microbes can be very different from each other, and have different effects. It's important to not just say that Lactobacillus does this, or even Lactobacillus rhamnosus does this, it's important to say Lactobacillus rhamnosus strain GG does this. Whether other Lactobacillus rhamnosus strains do it is the subject of potential research. So do you see the point I am trying to make?

You have to match up your strain with what you are talking about very carefully and precisely.

The products that you mentioned, the Activia, Culturelle, Align, and VSL#3 all do have well defined strains as components. I think you are also going to see development of medical applications. There are a very interesting couple of studies that were conducted in the area of vaginal health, and they showed for example, that taking a probiotic even orally improved the therapeutic treatment of bacterial vaginosis. This study was done in Africa, together with a group up in Canada. Including these specific probiotic strains as part of the treatment for bacterial vaginosis helped women get better more than just the standard therapy. So, I think we are going to see very specific medical applications for these microbes down the road.

Right, well excellent, I think this was a very engaging discussion, and thanks for taking your time.