Conditions that represent some of the leading causes of mortality worldwide—including obesity, diabetes, cardiovascular disease, and cancers—are linked with observable changes in the human gut microbiota. And many other chronic conditions, like inflammatory bowel disease, asthma and allergies, rheumatoid arthritis, and even myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), have also been linked with gut microbiota dysbiosis.
Scientists and the public have shown great excitement about these intriguing connections. It seems the gut microbiota, with its close links to metabolism and the immune system, could potentially be at the core of good health—that is, it might be at the “intersection” of the ongoing processes in our body that influence the risk of disease. In fact, my own work focuses on understanding how the gut microbiota influences metabolism and immunity in ways that contribute to a range of health parameters—most importantly, in obesity and type 2 diabetes.
Without a doubt, the potential of gut microbiota manipulation for improving human health is enormous. But at this stage, we need to ask the question: Will the gut microbiota end up being the solution to all of our health problems?
In my recent commentary in Nature Reviews Gastroenterology & Hepatology, I raised the question about what we expect for the future of gut microbiota science. With more than 3000 scientific papers on gut microbiota published in 2016, we have more data than ever before. Yet we need to make sure we are moving in the right direction.
The distinction between correlation and causation is of the highest importance when it comes to gut microbiota. Once a correlation between disease and gut dysbiosis has been established, scientists need to undertake well-designed experiments (including those in animal models) to figure out what is causing what. From there, we can develop new therapies that address the root cause of a disease.
Another barrier to moving ahead is the limited data we currently have. Most of the studies to date have taken a sample of the gut microbiota at one point in time—a single “snapshot”. It could turn out that one snapshot is not enough to know how we need to change the microbiota in order to improve health. Medicine has many examples that show a diagnosis cannot often be based on one measurement; rather, the right collection of things must be measured at the right times and interpreted together. In order to use gut microbiota for better diagnosis and treatment of the diseases we know, we will likely need to take into account not only the gut microbes, but also metabolites, host genetics, nutritional status, and regular dietary habits. Moreover, we will need to know when and how often to measure these things.
We are moving ahead step-by-step in understanding the role of gut microbiota in different diseases. In the decades ahead, some of the correlations we see today will likely yield useful new therapies, and others will not. Microbiota are constantly pressured by many different things—one of the most important and controllable being nutrition—and over time we will understand what makes an ‘ideal’ gut microbiota and how to aim for it by manipulating diet and other lifestyle factors, or by administering new medical treatments that target the gut microbial community.
So although it could be true that the gut microbiota is at the “intersection of everything”, we can’t let ourselves get ahead of the data. We must give these complex interactions time to unfold so we can arrive at a deeper understanding of the gut microbiota in health and disease.
Cani PD. Gut microbiota — at the intersection of everything? Nat Rev Gastroenterol Hepatol. 2017; 14(6): 321-322. doi: 10.1038/nrgastro.2017.54.
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