I wanted to highlight something that Mark Davis said in case it is helpful. It resonated with me because last summer I was researching probiotics and I came across this study:
Groeger, David et al. “Bifidobacterium Infantis 35624 Modulates Host Inflammatory Processes beyond the Gut.” Gut Microbes 4.4 (2013): 325–339.
It was a double-blind study, which is pretty rare among cfs results. It showed that taking a specific probiotic for 6 to 8 weeks decreased biomarkers of inflamation for cfs and other conditions. There are good reasons to be somewhat skeptical. I believe the study was paid for by the manufacturer and the commercial version is expensive and the patients in the study were given a dosage ten times the normal dosage. But I thought it was an interesting result.
The commercial product is called Align and I've been taking it for a year. My doctor thought it was worth trying, although he wasn't convinced that high doses were necessary long term. He mentioned that he takes Align himself.
In Mark Davis' talk, one of his bullet points was that, "Elevated cytokine levels that correlate with disease severity indicate a strong inflammatory component to CFS/ME." In the Q&A he mentioned that there are "probiotics that trigger helpful immune response that are available over the counter." When asked for clarification, he said, "bifido bacteria...you can buy it at Walmart."
I believe he was talking about Align or similar products. The fact that he mentioned Walmart makes me wonder whether he was thinking of a competing product called Equate that is cheaper. That uses a different strain of bifido bacteria than the one used in the study I mentioned, but it's not clear how important that is.
I haven't seen any big changes that I could detect, although I feel worse when I stop taking it. I'm using Align itself at a fairly high dose because my doctor agrees with the comment Davis made that, "it couldn't hurt," and I can afford it (Costco sales help). I think that major tinkering with your gut microbiome could cause harm, but I think that what Davis meant is that experimenting with this particular probiotic is probably safe if you can afford it.