The gut flora´s role in chronic fatigue syndrome

For many years, chronic fatigue syndrome/myalgic encephalomyelitis, or ME/CFS for short, was believed to be a psychiatric condition which should be treated through CBT and gradually increasing amounts of exercise. However, according to the World Health Organization (WHO), ME/CFS is a neurological illness. Though nobody knows what causes the condition, current research indicates that the answer may be in our gut.

ME/CFS is a chronic neurological systemic disease which affects multiple organs in our body, as well as our nervous system and immune system. The illness is often confused with exhaustion disorder. However, unlike exhaustion disorder or burnout, which occurs after an extended period of stress, ME/CFS is most often triggered by a viral or bacterial infection.

In addition to extreme tiredness that is not improved by sleep, memory problems and difficulties concentrating, ME/CFS can also produce symptoms such as muscle and joint pain, upset stomachs, headaches and hypersensitivity to light, noise and smells. Many people say the symptoms are a bit like having a case of the flu that won’t go away. Exerting yourself only worsens the condition. Simply making food or doing the dishes can be enough to make the symptoms worse and persist for several days or, in some cases, weeks after. Another difference is that more or less everyone with exhaustion disorder does eventually get better, even if it may take a while. The symptoms of ME/CFS can also improve but it is certainly not the case that all patients return to full health.

Tough to diagnose correctly

In Sweden, it is estimated that some 40,000 people, both adults and children, are affected by ME/CFS. The reason no-one knows the exact number is that many sufferers have either been misdiagnosed or never diagnosed at all.

ME/CFS has long been overlooked in health care and there is a great deal of uncertainty among doctors in Sweden and elsewhere over how to treat the condition. There are no common guidelines and knowledge about the illness is low. This makes it hard to get a correct diagnosis and the right treatment.

Recently, however, the UK’s National Institute for Health and Care Excellence, NICE, published updated guidelines, with therapy and gradually increasing amounts of exercise being eliminated as courses of treatment.

Immunological reaction

No-one currently knows what causes ME/CFS. Nor is there any sort of effective treatment for it. However, medications designed for pain, sleep issues and depression can alleviate symptoms. There are also ongoing studies into medications that affect the immune system. Research indicates that the mitochondria in the body are involved in the condition. Mitochondria are often referred to as the powerhouses of the cells since they convert food and acids into molecules which the cells can then use to transport energy. One theory is that with ME/CFS, the mitochondria have been impaired and are unable to produce enough energy-transporting molecules (ATP). Researchers believe that this state is caused by an immunological reaction suffered after an infection, for example, becoming chronic.

Gut flora a hot topic of research

One area that has been subject to intense research efforts for some years now is the significance of gut flora in cases of ME/CFS. Several studies have observed how microbes, meaning bacteria, fungi, yeast and viruses located in our gut, also known as gut microbiota or gut flora, are important when it comes to feeling good. It was previously thought that these microorganisms were harmful. Now we know that they are important for our health and that imbalances in our gut microbiota may be associated with several illnesses, such as inflammatory bowel disorders and even cancer, Type-2 diabetes and autoimmune rheumatological conditions like fibromyalgia and SLE.

Harmful imbalance

In a study published last year in renowned science journal Nature, a group of Italian scientists compared mouth and gut flora in ME/CFS patients and their family members against a healthy control group. What these researchers observed was that the ME/CFS group were lacking a group of bacteria in their gut called Firmicutes. They also exhibited inadequate levels of Lachnospiraceae, part of another family of bacteria. At the same time, they had an excess of the Bacteroidetes group of bacteria. All these bacteria are good and are a necessary part of our bowel system. It’s when they get out of balance and one group of bacteria takes over that they can become harmful. Quite simply, one strain of bacteria pushes out other good bacteria. In the study group, the researchers observed that family members of ME/CFS sufferers also had a milder imbalance in their saliva and gut flora compared to the healthy control group, indicating a connection with diet and lifestyle.

Researchers at the Israeli Weizmann Institute of Science are conducting similar work. A team of researchers at the Institute is using data algorithms for machine learning to investigate how the gut microbiota and immune system interact with one another and what role this plays in ME/CFS. One of the goals is that in future it will be possible to produce food and medicines tailormade for a certain individual. Because unlike our genes, the microbiota in our gut can be changed depending on what we eat.

Getting a handle on imbalances in the gut flora

It’s actually not so unusual that the microbiota in our gut can get out of balance. Many of us experience stress in our lives and this, combined with bad eating habits, upsets the natural gut flora.

So what should we be eating to restore the right balance? One subject capturing researchers’ interest for some years now is probiotics – lactic acid bacteria. In collaboration with the Karolinska Institute, a group of Swedish researchers recently investigated the effectiveness of a probiotic dietary supplement in patients with ME/CFS. The results are yet to be published.

In a Spanish study presented in 2018, researchers searched databases for controlled studies on probiotics and the connection to ME/CFS during the period 2006-2016. Two studies showed clearly that anxiety fell and stool composition changed in CE/MFS patients after they had been taking probiotics for 8 weeks. Inflammation biomarkers in these patients also fell during the same period.

A health benefit

According to the UN’s Food and Agriculture Organization (FAO) and the World Health Organization (WHO), probiotics are defined as “living microorganisms which when administered in adequate amount confer a health benefit on the host”. Put simply, you can find these microorganisms in raw, uncooked, acidic foods like apple cider vinegar, sauerkraut and other pickled vegetables. However, so that it can absorb and maintain these probiotics, our body also needs prebiotics, or fiber. Prebiotics can be found in foods like legumes, asparagus, bananas, oatmeal, almonds and honey. When probiotics are combined with prebiotics, they are known as synbiotics.

Although we don’t yet have an exact answer for how probiotics can prevent illnesses like ME/CFS or for how much of them we need in order for them to have any effect, it is undeniably a very exciting and important field of research.



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PI: Eran Segal, PhD Weizmann Institute of Science “Gut Microbiome & Autoantigens”

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