Granite Geek: The Digestive Possibilities of Probiotics

Jun 16, 2015

Probiotics are bacteria that help you digest, but they can also lead to digestive problems like inflammatory bowel disease to diarrhea, and there are also indications that they could be related to less obvious ailments such as allergies. Pros and cons of probiotics are at the heart of the next Science Café this Wednesday in Nashua. David Brooks, host of the Science Café, reporter for the Nashua Telegraph, and writer at, spoke with NHPR's Peter Biello. 

Give us a little more detail on what probiotics are, because as you write, it’s not just one type of bacteria.

No, it’s sort of a general term for what I think of as “gut health from bacteria.” It’s become a really interesting, exciting field in public health, which means it’s kind of confusing. Really within the last 5-7 years, it’s become obvious to researchers how important it is, the population of bacteria that live inside our stomach and intestines. It's hundreds of different species of bacteria that live in there, that do various things. Some of them don’t do anything, some grab nutrients out and help digest, some help pass along food, and some fight with each other. It’s an entire little jungle living in your gut.

Are these the same things as live cultures that exist in yogurt?

Sort of, and that’s really where a lot of the uncertainty is. And it’s a function of research. Research is relatively new in this field, and so there’s a lot of untested claims. Probiotics is not a drug, as I was told by one of the two dieticians who will be on our panel on Wednesdays. It’s not a drug, so it’s not regulated by the FDA. It’s called a “nutraceutical” or a health-giving food. Regulations are much, much, much looser and so there’s a lot of vague claims and hand-waving. It’s not at all clear, for example, if having a good bacteria in your yogurt, what it will do, whether it will do much of anything. I’ve heard some people say eating a probiotic bacteria is like dropping three monkeys into a jungle and expecting them to populate everything and it doesn’t necessarily work that way. And a lot of this stuff is designed to be evacuated from the system rather quickly. Particularly laymen, we have this idea that if you eat one good bug, it’ll turn into a whole bunch of good bugs in your stomach, and that’s not necessarily the case.

But if you did have a whole bunch of those good bugs, so to speak, it would help pass things through your system, possibly?

How many different euphemisms can we use, here? It could help do a lot of things. There is evidence that gut bacteria improves your oral health. It might improve allergies of all things. I’m not sure how that works. Skin health is one area that its been related to, so it’s not just irritable bowel syndrome. And this is why it has become such a hot field. You may have heard of fecal transplants. Which is a legitimate and really important and exciting field right now. For people who want to have specific bacterial problems in their gut, you basically implant feces from someone else into their gut, and that feces carries in all the bacteria mixed from the other people and repopulates the necessary bacteria in the patient’s gut and so now they can start digesting and they don’t have life-threatening diarrhea. That’s being done around the country. It’s legitimate, but there are some questions cropping up, which reflects how much we don’t know about gut bacteria. I’ve seen reports of people who, after they have this surgery done, it solves the medical problem but it has these weird consequences, side effects. One of which is, there’s a person who reported enormous weight gain who was always a thin person. She gained enormous amounts of weight and she can’t get it off. And apparently her donor was not a small person, so apparently there is some connection between whatever kind of connection was in the donor’s feces and weight gain, which is kind of surprising and interesting.

One of the things about this fecal transplant surgery is that the fecal matter that is transplanted could be rejected.

In the sense that the bacteria in it could be quickly flushed out of your system and not do anything, or it could interact in ways we don’t understand with existing bacteria. It’s extremely complicated. It’s an entire ecosystem, literally an ecosystem, and as we all know, ecosystems can be really complicated. By the way, I don’t know of any fecal transplant surgery being done anywhere in New Hampshire. If anyone knows about it, I’d love to hear about it.