Dr. Allan Walker, on the Harvard Probiotics Symposium

Dr. W. Allan Walker of Harvard Medical School was the chair of the organizing committee for the 2014 Harvard Probiotics Symposium. He caught up with Gut Microbiota for Health after the conference to give an overview of the event.

See our additional coverage of the Harvard Probiotics Symposium here.

What is the value of an event like the Harvard Probiotics Symposium?

First of all, as far as I know there’s never been another probiotics symposium that covers the life spectrum, so I think that was very good.

Secondly, we tried very hard to get the absolute authorities in the field… You probably appreciated the quality of the presentations. By getting that many people — we had over 450 who signed up — it allows for interaction at coffee breaks and at lunchtime. It also allows young people who are just starting in the field to get their posters up and get some feedback from some of the established investigators in the field. So there are lots of positive fringe benefits. It also tends to provide good information for practicing physicians who are perhaps interested in how commensal bacteria can help reduce the need for antibiotics and other things.

The audience was very eclectic and they brought up certain points that may or may not be valid, but at least it presented different points of view. If we had everyone from the same essential background and philosophy it wouldn’t be a worthwhile conference. We opened it to anyone who wanted to register and we got a very eclectic group of people who came.

In your view, what are some of the most important ideas presented at the conference?

There are some issues that came up in the symposium that I think need to be followed up: the importance of diet at all stages in life on the impact of microbiota, which in turn impacts on whether a person is healthy or develops disease. The comment that Dr. Stanley Hazen from Cleveland Clinic in Cleveland made, he quoted a review article that is about to be published… [it] points out what’s happening: lifestyle, including diet, influence intestinal bacteria, which in turn influence expression of disease. And this is shown by many of the investigators when they take either a human or experimental disease, take the microbiota from the patient with the disease, put it into a germ-free animal and [they] show the same symptoms, strongly suggesting that the microbiota are like an ancillary organ in the body. I think that’s something that needs to be pursued further.

We’re trying to incorporate now into the medical school curriculum more and more nutrition, since it’s such an important part of health. But one of the problems we see, because of excessive overweight and obesity, is doctors, because they don’t have a lot of background, fail to address that. And if they could do that very early on before someone gets excessively overweight, they could prevent a lot of the chronic diseases that we’re now seeing.

What cautions do you think emerged out of the conference?

What I tried to do was point out that the authorities in the field have outlined what is necessary before probiotics can be recommended.

As I said in my talk, lots of places think probiotics should be used so they go ahead and use it on their own. We can’t at this point come out and say to all neonatologists that you have to use probiotics for newborn prematures. We don’t have enough information on a specific protocol that we can recommend that. There are about 18-20 different protocols, and you can’t extract from a small study even if other studies seem to show an effect, until you go through these processes. So those kinds of things are difficult.

What are the next steps in your own research and practice?

My personal interest, because I’m a pediatrician, is “How we can maximize initial colonization of the newborn?” And that depends in part on the nature of how the baby’s born, whether it’s a natural delivery or whether it’s by caesarian section, whether or not the baby gets antibiotics in the perinatal period. And what we’re finding, and we have longstanding funding to look at this, [is] that breastfeeding is an important adjunct to normal delivery, and produces the optimum intestinal microbiota, leading to stronger health for the baby, and then the child and adult.

There have been a number of observations that have looked at optimum conditions for a baby. That is, natural vaginal delivery and exclusive breastfeeding for the first four months in the context of expression of disease later in life: there’s reduction in allergy, there’s reduction in diseases such as celiac disease, and some think, although that’s not as strongly proven, that that may also have an influence on whether a child becomes overweight and obese.