Gut microbes are tiny sensors of your general health

July 10, 2018 by Claire Steves, The Conversation
Gut microbe composition is fairly similar across a range of diseases. Credit: Perception7/

The number of studies that have found a link between a disease and a specific gut microbiome composition seems to be ever increasing. Until recently, though, almost all these studies have looked at single diseases in isolation. But most people tend to have more than one health complaint at a time – "comorbidities", in medical parlance.

For our latest study, published in Nature Communications, we studied the gut microbe composition across a range of diseases. What we found surprised us. The kind of microbes (such as Enterobacteriaceae) that increased in one , increased in pretty much all 38 diseases studied. Also, some microbes that might be considered to be "healthy gut microbes", were reduced in all 38 diseases studied.

We used data from the TwinsUK cohort, a unique group of older British twins who have shared their history, and many biological samples, for over 25 years. They are volunteers who, like all of us who have lived a while, have gathered health problems over time – 96% of the 2,700 who have donated stool samples have one or more .

The most striking finding from our analysis was that the microbes weren't specific to individual diseases, but rather to the state of general health. From a biological perspective, this makes sense. The environment that each bug likes is quite specific; anything that alters it, even slightly, means some sensitive bugs won't survive.

For example, the colon is a surprisingly low-oxygen (anaerobic) environment. Many illnesses lead to low level inflammation, which means that tiny blood vessels open and white cells creep out into tissues, including in the gut. White cells use oxygen as a weapon, so oxygen levels in the colon rise. This can be toxic to the normal gut bacteria, which evolved for strictly anaerobic conditions. An example is the friendly (yet frightening sounding) bug Faecalibacteria Prausnitsii which is wiped out in the presence of almost any disease.

The knock-on effect the loss of these friendly microbes has on a person's health is not yet known. They may simply be markers of , or they may actively contribute to good health. If they do contribute to good health, doctors will need to intervene early in the disease process to keep the friendly bugs alive. This might involve taking prebiotics (food for the friendly bugs) and probiotics, side by side.

In the future, researchers may even find a way to isolate your healthy gut bacteria and grow them outside your gut. Once enough have been grown, they could be reintroduced to your gut to boost your health. A personalised combination of healthy gut bacteria may be more likely to survive in your gut than a random implant of any good bacteria.

E. coli can survive in higher oxygen environments than the normal colon. Credit: CDC/Janice Haney Carr

Care in the community

A family of bacteria that increased in all the diseases we looked at was Enterobacteriaceae. These bacteria are adapted to survive in higher oxygen environments than the normal colon, and they include bacteria, such as E. coli, that can make you really ill. They also harbour high numbers of antibiotic-resistant genes.

Bacteria can pass special genes between each other (horizontal gene transfer) to survive an antibiotic onslaught. So if it turns out that bacteria that carry these genes are also found in people with multiple diseases, then that makes a difference to how we deliver safe, effective care for patients while maintaining infection control. For example, putting a bunch of vulnerable people together in a hospital is likely to create more opportunities for virulent strains of to evolve. We might need to invest more in treating people safely in their own homes.

Bug sensors and bug census

Our findings suggest that we could all benefit from being more aware of exactly what we are carrying inside us. Specifically, it suggests two things.

One, bugs are good sensors of our . So, in the future, we might want to consider over-the-counter poo tests to monitor our overall health. An early warning, such as a dip in anaerobic bugs, could help us to head things off at the pass. Subsequent tests could tell us if any of the action we have taken is working. If not, we can change tack.

Two, we should take a regular census of the bugs inside us, especially those associated with antibiotic resistant genes. The science is still in its infancy, but knowing where we are with these guys may help preserve antibiotics for when we really need them.

Explore further: How the microbiome could tackle antibiotic resistant infections in the lungs

More information: Matthew A. Jackson et al. Gut microbiota associations with common diseases and prescription medications in a population-based cohort, Nature Communications (2018). DOI: 10.1038/s41467-018-05184-7

Related Stories

How the microbiome could tackle antibiotic resistant infections in the lungs

August 10, 2017
Understanding how microbes contribute to respiratory health and immunity could help tackle drug resistant infections in the lungs, say scientists.

CDC: Drug-resistant 'nightmare bacteria' pose growing threat

April 3, 2018
"Nightmare bacteria" with unusual resistance to antibiotics of last resort were found more than 200 times in the United States last year in a first-of-a-kind hunt to see how much of a threat these rare cases are becoming, ...

Bugs as drugs: Harnessing novel gut bacteria for human health

May 4, 2016
Scientists at the Wellcome Trust Sanger Institute have grown and catalogued more than 130 bacteria from the human intestine according to a study published in Nature today.

Recommended for you

Fetal gene therapy prevents fatal neurodegenerative disease

July 16, 2018
A fatal neurodegenerative condition known as Gaucher disease can be prevented in mice following fetal gene therapy, finds a new study led by UCL, the KK Women's and Children's Hospital and National University Health System ...

New study finds that fat consumption is the only cause of weight gain

July 13, 2018
Scientists from the University of Aberdeen and the Chinese Academy of Sciences have undertaken the largest study of its kind looking at what components of diet—fat, carbohydrates or protein—caused mice to gain weight.

Basic research in fruit flies leads to potential drug for diseases afflicting millions

July 13, 2018
River blindness and elephantiasis are debilitating diseases caused by parasitic worms that infect as many as 150 million people worldwide. They are among the "neglected tropical diseases" for which better treatments are desperately ...

Light based cochlear implant restores hearing in gerbils

July 12, 2018
A team of researchers with members from a variety of institutions across Germany has developed a new type of cochlear implant—one based on light. In their paper published in the journal Science Translational Medicine, the ...

Researchers discover gene that controls bone-to-fat ratio in bone marrow

July 12, 2018
In an unexpected discovery, UCLA researchers have found that a gene previously known to control human metabolism also controls the equilibrium of bone and fat in bone marrow as well as how an adult stem cell expresses its ...

Intensive care patients' muscles unable to use fats for energy

July 12, 2018
The muscles of people in intensive care are less able to use fats for energy, contributing to extensive loss of muscle mass, finds a new study co-led by UCL, King's College London and Guy's and St Thomas' NHS Foundation Trust.


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.