Mary Ellen Sanders, Ph.D., Probiotics Interview: Part I

Tuesday, March 20, 2007 - 9:52am

Can you start us with an introduction of yourself?

Okay. My name is Mary Ellen Sanders. I have a PhD in Food Microbiology, so my focus in the Probiotic area is from a Microbiological prospective. I am not a dietitian or a clinician of any sort either. I initially did research in the area of the Genetics of Lactic Acid Bacteria, which includes some of the microbes that are used as Probiotics. And, that was years ago, but for the past seventeen years I have worked for myself, and have consulted with Dairy, Dietary Supplement, and Food Industry Companies in the area of Probiotics.

I have also worked with some nonprofit organizations, such as the California Dairy Research Foundation, and with other organizations like the International Scientific Association for Probiotics and Prebiotics, and other professional organizations, trying to do what I can to further this science of the field of Probiotics. I consider myself an expert not only in the Microbiology, but also the way these Microbes can mediate health effects.

Can you give us a definition of Probiotics?

Sure. Probiotics actually have been defined in the published literature in a variety of different ways. But the definition that I prefer is one that was adopted in the year 2001 by a group of experts that were convened by the FAO to look at the use of Probiotics in foods. They defined Probiotics as live microorganisms which when administered in adequate amounts confer a health benefit on the host. I like that definition for a couple of reasons; first of all it doesn't imply a mechanism of action--so many of the definitions that you might see might specify the method of action, such as enhancing immune function. To me, if you can demonstrate a health effect that is caused by the microbe that's being consumed or applied, then it qualifies as a probiotic, regardless of the specific mechanism that mediates the effect.

The other key element of that definition is the microbes have to be alive. There are publications that have come out that have documented some effects of dead microbes. And, that's completely fine and they may even overlap in some mechanistic way with live microbes, but that's just something else, that's not probiotics. So, the term probiotic has to be reserved for live microbes. Also, notice the definition doesn't say that it has to be consumed or eaten. This particular definition does allow for the idea that probiotics maybe used in ways beyond consumption.

There might be, for example, vaginal suppositories that are made with using live microbes that would also be considered a probiotic. Note that our European colleagues almost exclusively consider probiotics dietary. I just think it's worthwhile to say that there can be a subset of probiotics that are not dietary.

So, let's talk a little bit about the number of organisms that we naturally carry around with us, which are part of a healthy human body.

Right. That's an important context to provide. I do think that people have a sense that live cultures can be beneficial. There is part of our society that does recognize that there maybe value to that. But, I don't think people always recognize that those are bacteria. They think that cultures are "good" but bacteria are "bad" But of course, not all bacteria are bad. Probiotics are beneficial to health. And we are colonized by lots and lots of bacteria that we are finding can be very important to health.

When you take probiotics, and you might be consuming them as part of a product anywhere from let's say a hundred million up to a hundred billion per day. Well, that sounds like an awful lot of live microbes to be adding to your system. But, in fact we have about a hundred trillion microbes that are colonizing our bodies, and there is a very fascinating area of research that's going on right now about what impact they have on us.

Dr. Jeff Gordon at Washington University in St. Louis and others are heading up some great scientific experiments that really are focused on trying to understand how our native microbes interact with our bodies. Years ago people would say well, we carry these microbes around, but that was about the extent of it. But, in fact this research is starting to show that those microbes interact quite intimately with our body cells as they either live or travel through our bodies.

And, there are immune cells that are specifically focused on being able to sense the microbes, and the microbes actually communicate back to our cells. And, that type of communication is very important in immune system development. And, so we have learned over recent years that we are colonized by a huge number of microbes.

There is also a huge diversity of microbes. They estimate that over maybe a thousand different species, or what they like to call operational taxonomic units these days, have been associated with humans. Note that any one individual might not carry that many. But, they've identified many different types of microbes associated with human beings, and so there is a large diversity of microbes, and a large number of microbes, and these microbes aren't just static, they are in a dynamic relationship that has evolved with us.

So, we provide an environment for the microbes to live, and then the microbes help to provide our bodies what they need to develop properly. And, that's been the case since the beginning of human evolution. I think that it's a very important point to make that microbes are being found to be very important to our normal growth, development, and physiology.

That's the context, because then the probiotic hypothesis comes in and says, given the value of these colonizing microbes, can you add externally additional microbes to that very complex system that we just described, and have an positive affect?

Right. One would presume that not everybody has the microbes in perfect balance.

Well, yes and no. Every probiotic site you find online is going to talk about how probiotics improves "microbial balance". I don't know how to get my arms around that concept scientifically, since balance may mean different things to different people; by balance do you mean, the optimal numbers and types of microbes there? Or do you mean they maintain this particular composition over a course of time? If what you mean by balance is that our microbes are relatively stable over time, then I think your point is probably right. But although it is hard to believe that we all have the optimal composition of microbes, no one knows exactly what the optimum microbial composition is.

For example you and I will be very different. You might have many more microbes that I do, or have many types of microbes than I do. Even though the literature is replete with discussions about this, I don't know that we really scientifically can define what that optimum balance means. Until we have a better sense of what contribution all these different types of microbes offer, we are a long way from saying "this is better for you than that". That almost sounds like I am totally undermining the whole concept of probiotics. But, the probiotic hypothesis states that if you add microbes to that system, you can have an effect, and now the question is Well, what do the experiments say, what does the science say?

And, there have been quite a few controlled human studies that have shown yes in fact, by adding the right types and levels of microbes to a fully colonized, even reasonably healthy person, you can have an effect on health. The probiotic hypothesis is gaining steam, because there have been well-controlled, well-conducted studies that have documented specific positive effects. There is also reasonable hypothesis for why they can work, because we do know these colonizing microbes have an important role in health.

Right, The important thing is that there is science that shows that certain ways of tinkering with the system have beneficial effects.


So what we do know is that certain things, when added to the system, seem to reliably show a beneficial effect.

I think that's well stated. In addition, we know the typical Western diet is pathetically low on fiber, and oligosaccharides that can nourish beneficial microbes. Especially, in comparison to what it was centuries ago. We also know that we are no longer living close to the soil as we did hundreds of years ago. Back then we ate raw fruits and vegetables which have an incredible compliment of microbes that were being carried along with them. Our foods are processed, and even raw fruits and vegetables will carry some microbes, but they are so clean now compared to what we used to eat.

Our children are born in hospitals, so they are not being colonized by their environments often times, or they are even born with caesarian delivery. So, they are not being colonized even with the vaginal flora of their mothers. Maybe there is this artificial situation that has developed where the microbes haven't had a chance to colonize us in an optimal way. Based on this, we believe that there is value in trying to feed the system with microbes, because our Paleolithic ancestors did that. And, we just don't do it very much, and that's a theoretical concern.

Mary Ellen Sanders, Ph.D., is an internationally recognized consultant in the area of probiotic microbiology. She helps food and supplement companies develop new probiotic products and provides technical support for enhancing existing probiotic product lines. She works with non-profit organizations to develop strategies for research and market development for probiotic products. She has extensively reviewed the technical literature on probiotics, published on the science and marketing of probiotic bacteria, coordinated clinical studies to validate probiotic efficacy, updated the FDA on the topic of probiotics, served on GRAS determination panels, participated in a working group convened by the FAO/WHO to make recommendations to Codex for guidelines for use of probiotics and serves on the Product Quality Working Group of the NIH National Advisory Council for Complementary and Alternative Medicine.