You may fondly think of yourself as human, but the trillions of microbes that call your body home might consider that a little inaccurate. These microbes — mostly bacteria — take up residence in every nook and cranny in the body. Collectively, they’re called the microbiome. But we’re not just taking them along for the ride: new evidence shows these bugs affect—and reflect—our health in many critical ways.
Already, the microbiome has been implicated in everything from the severity of autism symptoms and the detection of Parkinson’s disease to the prognosis of patients with cancer. When our microbial populations go awry, it turns out, terrible things can happen.
Scientists have been working to catalog the human microbiome for decades. It’s a real challenge: for each site in and on the body, researchers have to get a fair accounting of the microbes that live there, the proportions of certain bacterial strains in each little population, and figure out how to discern a healthy community from an unhealthy one. Technical innovations—including highly sensitive DNA sequencers and sophisticated algorithms that unravel the data—have allowed for huge progress.
Academic institutions and companies sensing the potential of this field have jumped in, sometimes too fast. Some companies have skimmed superficial data and slapped together scientifically unfounded “health” offerings that target unsuspecting consumers. The resulting surge in probiotics and other consumer-oriented products, based largely on rudimentary science, threatens to dilute the benefits of a promising microbiome industry. Today may only be the infancy of the microbiome field, but experts estimate the global value of these products at as much as $400 million, with some predictions breaking $1 billion within five years.
Recently, some of the biggest and best microbiome research has been published — biggest because of the funding levels and sheer size of these studies, and best because the long-term nature of these projects makes the results more meaningful in helping scientists accurately describe the human microbiome. The research will be incredibly important for ensuring that development of new microbiome products builds on a strong scientific foundation.
These studies, launched through the National Institutes of Health’s Human Microbiome Project, focused on three major areas: inflammatory bowel disease (IDB); diabetes; and pregnancy and preterm birth. Study participants had their microbiomes sampled repeatedly over time — one study followed people for four years — to better understand natural short- and long-term changes in the microbiome ecosystem. The IBD study showed that people with the disease had more unstable microbiomes compared to people without it. The diabetes study highlighted microbiome differences between patients who are sensitive or resistant to insulin, and suggested some intriguing links to the immune system’s response to respiratory infections. Finally, the pregnancy study identified specific microbial signatures in women who experienced preterm birth.
This information will be critical for translating research results into much-needed clinical interventions. Research is being paired with the development of new kinds of measurement and reporting technologies to ensure that the data being collected is as accurate and reliable as possible. Already on deck: swallowable sensors that collect microbial data as they traverse the body; the creation of data standards to create a clear, replicable way to describe and share results; and lab mice colonized with a characteristically human microbiome so that preclinical studies using mice are more likely to mimic results from humans.
Ideally, the goal is to develop products such as live-microbe therapies that could be used in lieu of conventional pharmaceutical drugs to treat any health condition influenced by the microbiome, such as giving an IBD patient microbes associated with healthy guts to alleviate the effects of the disease. While it’s tempting to presume the safety of treating people with microbes that are already well-tolerated by human bodies, there have been some early red flags. This year, the U.S. Food and Drug Administration issued a safety alert after a patient died from receiving a fecal microbiota transplant; the transplant contained dangerous drug-resistant bacteria and led to a deadly infection. In a less life-or-death scenario, scientists surveyed commercially available probiotics and found that two-thirds did not provide sufficient information to prove that their health claims were based on real evidence.
With appropriate precautions, though, there is enormous opportunity to improve human health by taking better care of our microbes. The field needs more funding, more research, and more global cooperation to ensure the best possible results. Recently, philanthropists Marc and Lynne Benioff donated $35 million to Stanford and the University of California, San Francisco, to establish new microbiome research institutes. No doubt much more interest — and funding — will follow.