There is tremendous current interest in the
relationship between the microbes in and on our bodies and our state of health
and disease. The origins of chronic fatigue syndrome (CFS) have been
mysterious; studied for years. This
problem is now believed to be related in some ways to the bacteria in our
gut.
CFS is a condition where normal exertion leads
to debilitating fatigue that isn't alleviated by rest. There are no known
triggers, and diagnosis requires lengthy tests administered by an expert. Now, for the first time,
Cornell University researchers report they have identified biological markers
of the disease in gut bacteria and inflammatory microbial agents in the blood.
In
a study published June, 2016 in the journal Microbiome, the team
describes how they correctly diagnosed chronic fatigue syndrome in 83 percent
of patients through stool samples and blood work, offering a step toward
understanding the cause of the disease.
"Our
work demonstrates that the gut bacterial microbiome in chronic fatigue syndrome
patients isn't normal, perhaps leading to gastrointestinal and inflammatory
symptoms in victims of the disease," said Maureen Hanson, a professor in
the Department of Molecular Biology and Genetics at Cornell and the paper's
senior author. "Furthermore, our detection of a biological abnormality
provides further evidence against the concept that the disease is psychological
in origin." The researchers
concluded that when they have more information, clinicians could consider
changing diets, using prebiotics such as dietary fibers or probiotics to help
treat the disease.
Cornell
researchers collaborated with Dr. Susan Levine, a CFS specialist in New York
City, who recruited 48 people diagnosed with CFS and 39 healthy controls to
provide stool and blood samples.
The
researchers sequenced regions of microbial DNA from the stool samples to
identify different types of bacteria. Overall, the diversity of types of
bacteria was greatly reduced and there were fewer bacterial species known to be
anti-inflammatory in CFS patients compared with healthy people, an observation
also seen in people with Crohn's disease and ulcerative colitis.
At
the same time, the researchers discovered specific markers of inflammation in the
blood, likely due to a leaky gut from intestinal problems that allow bacteria
to enter the blood. Bacteria in
the blood will trigger an immune response, which could worsen symptoms.
The
researchers have no evidence to distinguish whether the altered gut microbiome
is a cause or a whether it is a consequence of disease. In the future, the
research team will look for evidence of viruses and fungi in the gut, to see
whether one of these or an association of these along with bacteria may be
causing or contributing to the illness.
Probiotics are microorganisms that are
believed to provide health benefits when consumed. The term probiotic is currently used to name
ingested microorganisms
associated with benefits for humans and animals. The introduction of the
concept is generally attributed to Nobel recipient Élie Metchnikoff,
who postulated that yogurt-consuming Bulgarian peasants lived longer lives
because of this custom. He suggested in 1907 that "the dependence of the intestinal microbes on the
food makes it possible to adopt measures to modify the flora in our bodies and
to replace the harmful microbes by useful microbes.” Although some claims for probiotics have not been
substantiated, randomized
controlled trials at the University Hospital, Tuebinden, Germany, published
in 2016, found that certain commercially available strains of probiotic
bacteria when taken by mouth
in adequate doses for 1–2 months, possess treatment efficacy in certain psychological
disorders, e.g. anxiety,
depression,
autism spectrum
disorder, and obsessive-compulsive
disorder – and improved certain aspects of memory.
Prebiotics are non-digestible fiber compounds that pass
undigested through the upper part of the gastrointestinal
tract and stimulate the growth or activity of advantageous bacteria that colonize the
large bowel by acting as substrate
for them. Most fruits and vegetables have indigestible fiber. Some most
effective prebiotics include onions, garlic, leeks, wheat bran, asparagus,
chicory, and raw banana.
There
will be a symposium on the microbiome, in healthy soil and in the human body,
on Sunday, December 4th at 2pm, at Commonweal in Bolinas. The microbiome is a subject of
substantial current research and excitement, with a relationship to many
aspects of health and disease. Please attend if you are interested!
Sadja Greenwood, MD, MPH
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