Causes of dysbiosis[edit | edit source]
Psychological stress[edit | edit source]
Infection[edit | edit source]
ME and CFS[edit | edit source]
There is strong evidence that dysbiosis or an imbalance in the microbial ecology of the gut plays a role in the symptoms of ME/CFS. On average, ME/CFS patients have lower levels of Bifidobacteria, Escherichia coli and higher levels of aerobic bacteria, in particular Enterococcus and Streptococcus species. The latter produce D-lactate, a form of lactic acid only produced by non-human cells that is poorly metabolized in humans. D lactate is associated with a wide variety of cognitive and neurological symptoms, such as in patients who suffer from D-lactic acidosis. A study found that higher levels of enterococcus bacteria in CFS patients were associated with more severe neurological and cognitive dysfunction.
One hypothesized consequence of dysobiosis is an overproduction of hydrogen sulfide (H2S) by pathogenic bacteria. H2S can inhibit mitochondrial respiration by blocking cytochrome c oxidase.
A study of Norwegian and Belgian patients found significantly decreased proportions of Firmicutes genera Holdemania and increased proportions of bacteroidetes genera Alistipes in the Norwegian but not the Belgian sample. Significantly increased proportions of Firmicutes genera Lactonifactor were found in both.
References[edit | edit source]
- Chronic fatigue syndrome: lactic acid bacteria may be of therapeutic value
- Sheedy, John R; Wettenhall, Richard EH; Scanlon, Denis; Gooley, Paul R; Lewis, Donald P; McGregor, Neil; Stapleton, David I; Butt, Henry L; De Meirleir, Kenny L (Jul 2009), "Increased d-lactic Acid intestinal bacteria in patients with chronic fatigue syndrome", In Vivo, 2009 Jul-Aug;23(4): 621-8, PMID 19567398
- Myalgic encephalopathy--chronic fatigue syndrome : the medical practitioners'--challenge informed accurate diagnosis : proceedings of international clinical and scientific meeting, Sydney, Australia, 1-2, December 2001. Ring, Jenny., Alison Hunter Memorial Foundation. Bowral, Australia: Alison Hunter Memorial Foundation. 2002. ISBN 9780958186506. OCLC 52595685.
- Frémont, Marc; Coomans, Danny; Massart, Sebastien; De Meirleir, Kenny (Aug 2013). "High-throughput 16S rRNA gene sequencing reveals alterations of intestinal microbiota in myalgic encephalomyelitis/chronic fatigue syndrome patients". Anaerobe. 22: 50–56. doi:10.1016/j.anaerobe.2013.06.002.
Myalgic encephalomyelitis or chronic fatigue syndrome