Our bacteria are more personal than we thought, Stanford Medicine-led study shows

The data turned up another surprise: The microbiomes in different places in the body were highly correlated. Even though different types of bacteria are present, when the microbiome of one body area changes, the others also shift. If the nasal bacteria change at the onset of a respiratory infection, for instance, the gut, mouth and skin microbes quickly start to change as well. When the gut bacteria shift with diabetes, so do the bacteria on the skin, mouth and nose.

Connections to health

Based on the blood samples taken throughout the study, Snyder’s team suspects the immune system is the common link connecting the microbes in different areas of the body — and connecting overall health within the microbiome. Levels of certain immune proteins in the blood changed in sync with the microbiome. In addition, lipids — fats in the blood — were also associated with change to microbiome stability, explaining some of the link to diabetes.

The group pinpointed several environmental factors that played roles in shaping the microbiome: Microbes predictably shifted with the seasons, for instance, likely due to changing humidity and sunlight levels as well as fresh food availability. But these environmental factors, including diet, still didn’t explain much of the variability between people.

The new data, the researchers said, closes the door on the idea that there is a gold standard microbiome everyone should be trying to achieve for optimal health.

“Instead, we’re moving toward this idea that we have a personal microbiome that is incredibly important for our own metabolic and immune health. Our metabolic and immune health also greatly affect our microbiome — it is all tied together. The microbiome varies enormously between people,” Snyder said. “How you feed it and what it’s exposed to probably makes a big impact on your health, and we still have to work that out in many ways.”

Researchers from University of Oxford, Ohio State University, uBiome, Oregon Health & Science University, Yale University, Shanghai Jiao Tong University, Zhejiang University, Texas Tech University, Agrosavia, and University of Connecticut were also involved in the study.

Funding for this research was provided by the National Institutes of Health Common Fund Human Microbiome Project (grants U54 DE023789-01, U54 DK102556-03, R01 DK110186-05, S10 OD020141-01, R01 AT010232-04, UL1 TR001085, P30 DK116074 and S10 OD023452-01), the Leona M. and Harry B. Helmsley Charitable Trust, and the Innovative Medicines Accelerator.