Podcast: Modern Medicine May Not Be Doing Your Microbiome Any Favors

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About the Speaker

There are lots of theories about why food allergies, asthma, celiac disease and intestinal disorders like Crohn's disease have been on the rise. Dr. Martin Blaser speculates that it may be connected to the overuse of antibiotics, which has resulted in killing off strains of bacteria that typically live in the gut.

Blaser is an expert on the human microbiome, which is the collection of bacteria, viruses, fungi and other microbes that live in and on the body. In fact, up to 90 percent of all the cells in the human body aren't human at all — they're micro-organisms.

Blaser is the director of NYU's Human Microbiome Program and a former chairman of medicine there. His new book is called Missing Microbes: How the Overuse of Antibiotics Is Fueling Our Modern Plagues.

Interview Highlights

On why he thinks the number of diseases has risen

Since World War II, we've seen big rises in a number of diseases: asthma, allergies, food allergies, wheat allergy, juvenile diabetes, obesity. ... These are all diseases that have gone up dramatically in the last 50 or 70 years. One of the questions is: Why are they going up? Are they going up for 10 different reasons, or perhaps there is one reason that is fueling all of them.

My theory is that the one reason is the changing microbiome; that we evolved a certain stable situation with our microbiome and with the modern advances of modern life, including modern medical practices, we have been disrupting the microbiome. And there's evidence for that, especially early in life, and it's changing how our children develop.

On the potential link between antibiotics and obesity

We have experiments in mice where, since we're very interested in obesity, if we put mice on a high-fat diet, they gain weight; they get fat. If we put them on antibiotics early in life, they also get fat. If we put [them] on both together, they get very fat. ... It's clear that the effects of the antibiotics potentiate the effects of the high-fat diet. We're not letting [the] high-fat diet off the hook, we're saying that there's another factor there. ...

There's a choreography; there's a normal developmental cycle of the microbiome from birth over the first few years of life, especially the first three years, [that] appear[s] to be the most important. And that's how nature has, how we have, evolved together so that we can maximize health and create a new generation, which is nature's great purpose. And because of modern practices, we have disrupted that. And then the question is: Does that have consequence[s]? Our studies in mice show that it does have consequences. We've done epidemiologic studies in people that show that some of these modern practices are increasing the risk of obesity as well.