Dr. Erika Isolauri is a professor of paediatrics at the University of Turku, and chief physician at the Department of Paediatrics at Turku University Hospital in Finland. At the 2014 Harvard Probiotics Symposium she presented a talk entitled Probiotic Use During Pregnancy for Protection Against Childhood Diseases. She sat down with Gut Microbiota for Health after the event to describe more about her research and clinical practice.

Some of the speakers at the 2014 Harvard Probiotics Symposium. Dr. Erika Isolauri, centre.

Some of the speakers at the 2014 Harvard Probiotics Symposium. Dr. Erika

How did the microbiota become a topic of interest for you within paediatrics?

From patient work. I had two lines of research, one was treatment of acute diarrhea, and the other was food allergy and atopic eczema. And then we learned how you can improve: you give milk to diarrhea patients, and if you use fermented milk or probiotics milk, you can strengthen their [gut] barrier and shorten their recovery.

Then, in the other line of research, I saw that atopic eczema children have [altered antigen transfer in the gut]. And then I applied the information I got from the diarrhea studies. Actually, the idea came from my PostDoc. We were working in France, I was in Paris at that time. So we looked at how the gut barrier functions, how diet modifies the structure in diarrhea or other impaired barrier function states, and then we applied it to patients.

I saw many effects – very good responses in practical work. So therefore I always mention: listen to the patients and learn from their experience. Believe what they say and not necessarily what the textbooks say.

What role do probiotics play in immunity through the microbiota?

It’s not only through the microbiota. Probiotics have immunomodulatory effects. They do work in the lower part of the gut and modify the composition but they have many other effects. One is that they strengthen the gut barrier in the small intestine, so they affect how antigen uptake is taking place.

Also the antigen transport and the mucine layer is enhanced, and tight junctions are enhanced. And also, the pro-inflammatory gut microbiota is changed, the barrier is changed, and also [there is] some effects on antigens: they degrade antigens. They enhance IgA immunity and IL-10 production, TGF-b production.

Many of these effects take place in other locations than where we have our fecal microbiota. It is shown there also that we have a transient effect on the gut microbiota. But if we have this effect, and control inflammation during the critical stage of development, we can have lasting effects in clinical terms. So it is not about the microbiota as such.

Can you describe how antibiotics and probiotics can be balanced to achieve the best outcomes for children?

To make it simple, antibiotics “bad” and probiotics “good”. But [it’s] not always that way. Many newborns receive short courses of antibiotics… when they have a suspected infection, and then that is stopped. And [even] these short-term antibiotics might do exactly the same thing as [in] the mouse model – so that they [may] have lasting effects on immunological maturation and so on.

Probiotics promote controlled inflammation while antibiotics sort of wash away everything. Like in diarrhea patients, all microbiota is washed away and the Staphylococci… are the ones coming [back] first, and they lead to chronic diarrhea. Of course when you have a condition, you need antibiotics to stop the condition early. I’m not an anti-antibiotics person. But I would say not [to use them] for preventative purposes. For example, a caesarean section does not require antibiotics but [they are] given for some reason. We have given that up a long time ago in [Finland].