Firmicutes/Bacteroidetes Ratio Seen in CFS and other diseases

The best starting point is to get a uBiome done. It is unlikely that you are high in ALL bacteria genus (a lower level of identification). The uBiome will identify the genus that are high.

At a very high level, CFS patients always have a shift in the Firmicutes:Bacteroidetes ratio. But the shifts on an individual level can be up or down by as much as a factor of 10x. When there have been studies, the study group will often have a pattern.

So depending on your specific shift, you may wish to increase or decrease dairy intake. No magic recommendation for all -- specific recommendation based on your actual microbiome.

The Firmicutes/Bacteroidetes ratio is a rough indicator of bacterial shifts. The following are not included in these gtoups: Bifidiobactium, Escherichia coli

Firmicutes: Includes Lactobacillus, Enterococcaceae, Bacillus. Usually Gram-Positive

Bacteroidetes usually gram-negative

Not in either of the above: Bifidiobactium, Escherichia coli

When the ratio increases then either

  • More firmicutes
  • Less bacteroidetes
  • or both with firmicutes increasing faster.
When the ratio decreases then either

  • Less firmicutes
  • More bacteroidetes
  • or both with firmicutes decreasing faster.

Lower Ratio
  • Systemic lupus erythematosus [2017]
  • Coeliac disease [2016]
  • Crohn’s Disease [2016]
  • Aging [2014]
Higher Ratio
  • Obese (higher BMI) [2017]
  • Gut dysbiosis in hypertension [2017] [2017]
  • Autism spectrum disorders [2017]
  • Chronic Fatigue Syndrome [2013]
  • Gulf War Illness [2017]
  • Irritable bowel syndrome [2016] [2016] 3x higher
  • Sjögren’s syndrome [2007]
  • Rheumatoid Arthritis [2014] ” The signs of III degree dysbiosis, by reducing the concentration of Bacteroides spp., Bifidobacterium spp., Lactobacillus spp. populations, typical strain E. coli. But over growth of populations Klebsiella spp., Proteus spp., Staphylococcus spp., atypical forms of E. coli, Candida spp. ” Almost the identical pattern reported for CFS in 1998.
  • Increases
    • capsaicin [2016]
    • Dairy products [2016]
  • Decreases –
    • Resveratrol [2014]
    • Lactobacillus Fermentum [2017]
    • Pea Fibre [2017]
    • Melatonin [2017]
    • Cranberry [2017]


Thank you so much! I've been researching this when I can and it's really useful to have this chart putting a lot of the F/B ratio implications together for CFS :)
Sorry I'm too brain fogged, does this mean we should avoid dairy and capsaicin if we have CFS? I will click on the links to try and answer this myself!

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