A new study in Nature “Elevated blood lactate in resting conditions correlate with post-exertional malaise severity in patients with Myalgic encephalomyelitis/Chronic fatigue syndrome”  re-affirms many earlier studies. ME/CFS patients have increased level of lactate acid. One probable cause is LABO – Lactic Acid Bacterial Overgrowth, a possible variation of SIBO – Small Intestine Bacterial Overgrowth.
I have written about this in prior posts:
- The Dilemma of D-Lactate Free Probiotics – they do not work.
- Approaches to D-Lactic Acid Acidosis (2015)
- D-lactic Acidosis -Sauerkraut is not good for you if you have CFS! (2015)
- Large dosage of thiamine  can help. See these posts
I have also created a list of common probiotics that contain lactic acid producers. The list is here. These are probiotics that should be avoided.
NOTE: This is just one viable model. Another model is too few lactic acid consumers. Another model is acute and chronic hepatic insufficiency . If you have uploaded your microbiome, you can see your relative ranking for production (with a crude estimate for the amount)
In addition to the above, the microbiome prescription site site has a option to explicitly reduce the lactic acid producers in your microbiome.
When you go to Advance Suggestions and click see Bacteria Selection Choices
You will find at the bottom of the page, a new section: the Lactic acid/Lactate producing bacteria reported in your sample where you have more than the median amount.
Back on the custom suggestion pages, I select this filter option, as shown below.
Then filter the modifiers and click for suggestions:
This is all theoretical and focuses solely on reducing bacteria associated with lactic acid and lactate production. The suggestions should be reviewed by a medical professional before starting. It may potentially make other issues worst, so use caution and make sure you are being monitored.