Welcome to the first instalment of Between the Pages, where I read and review books about science.
If science was Hollywood, the microbiome would be its new It Girl. The paparazzi report on its every move to see which new disease or condition it will be associated with next. Fans clamor to buy the newest supplement that promises to restore your microbiome to a “healthy” state.
Feeling a bit late to the party? Let’s bring you up to speed. Simply put, the human microbiome is the collection of microorganisms that share our body. These include the bacteria, viruses, and fungi that live on our skin, in our mouths and digestive tracts, and in all our bodies’ little nooks and crannies. Even though they are microscopic in size, their numbers are daunting: there are 10 microbial cells for every human cell in our body! Most of these microorganisms are beneficial to us. They help us digest food and extract nutrients that we wouldn’t be able to get on our own. They strengthen our immune system so that it can better recognize and fight off invading pathogens. They prevent harmful microbes from taking hold in our bodies by depriving them of important nutrients. So, that’s great! Three cheers for our microbiome!
But what happens when our microbiome changes and the balance of species is shifted? As Dr. Martin Blaser argues in his book Missing Microbes, that’s when things start to go wrong. Blaser, who heads up a large lab at New York University, has studied the role of bacteria in human disease for the last thirty years. He is also the director of the Human Microbiome Project at NYU and has published many scientific papers on the subject.
In Missing Microbes, Blaser contends that modern practices, such as the misuse and overuse of antibiotics and the growing popularity of C-sections, are causing dramatic changes to our microbiome by killing helpful bacteria and allowing harmful species to grow. These changes are, in turn, driving what he calls “the modern plagues”: diabetes, obesity, asthma, allergies, and certain types of cancer. The book covers a wide breadth of topics, from the discovery of penicillin in 1928 to the use of antibiotics in modern farming to the complex interactions between mother, child, and microbes during pregnancy and childbirth. There are also individual chapters devoted to each of the modern plagues, where Blaser presents evidence from scientific studies that demonstrate a link between changes in the microbiome and a specific condition.
Overall, the book does a good job of raising the alarm on our overuse of antibiotics. In fact, it does its job so well that Blaser received an “Overselling the microbiome” award from Dr. Jonathan Eisen, a professor at the University of California, Davis who has been researching the microbiome long before it was cool. I am inclined to agree with Dr. Eisen. Most of the studies described in the book actually show correlation between changes in the microbiome and human health. Based on what we currently know, it is very difficult to say, with certainty, if the changes in our microbiome are a cause or an effect of conditions like obesity and allergies. Establishing causality remains one of the biggest challenges in the field, a fact that Blaser neglects to mention.
Far from being an unbiased survey of all of the relevant research on microbiome and human health, the book spends a disproportionate amount of time discussing research by Blaser and his wife, fellow NYU microbiome researcher Dr. Maria Gloria Dominguez-Bello. While their studies have undoubtedly made significant contributions to our understanding of the microbiome, I couldn’t help but wonder about other labs around the world who are doing equally exciting and ground-breaking research.
The way I see it, the consequences of overusing antibiotics fall into two categories: antibiotic resistance and everything else. We are seeing more and more cases of drug resistant infections in hospitals worldwide. The overuse of antibiotics in medicine and agriculture has generated enormous selection pressures that directly fuel the rise in drug resistance. The UK government recently published a comprehensive review of the staggering economic and human costs of antimicrobial resistance. This is a big BIG problem. Forgetting about everything else, the magnitude of the drug resistance problem alone should be sufficient to caution people against haphazardly taking antibiotics when they have a viral infection and to encourage consumers to demand stricter enforcements on the use of antibiotics as growth promoting factors in animal feed.
But maybe drug resistance isn’t sexy anymore. Maybe sensationalizing ideas like “How antibiotics are making you fat” on Dr. Oz is the only way to get the message out. If that’s the case, then at the very least, this book has brought the misuse and overuse of antibiotics to the public conscious as an important topic for debate and discussion. But, really, Dr. Oz? Major respect lost for that one.