I restarted taking probiotics and around the same I started to get depressed. Maybe a coincidence, but I think it could be die-off/herx. If this is the case then I take it as a good sign that they're doing their job and fighting off the "bad guys".
There was a very interesting study in mice on probiotics and depression just a few months ago:
Next, the researchers severed the vagus nerve, which helps alert the central nervous system to changes in the gastrointestinal tract. They found the bacteria-induced effects on behavior and GABA receptors were diminished, suggesting this nerve is the pathway by which changes in the gut can influence the brain.
I know that studies in humans on depression and probiotics also have shown benefits.
I also had a bad reaction to probiotics in the past, but this past Fall, when my stomach went crazy (possibly an infection, it was horrible cramping that went on for weeks), probiotics saved me. I started taking them 3x a day and if I missed a dose, it was bad. I was loathe to try them at all because in the past they had given me intestinal cramps, but instead, they were great.
Most recently, though, I do have a lot of brain fog, but I've also been sick and am starting on methyl folate with a lot of disrupted sleeping, so, it's not clear if they have a role.
I think the dangers of probiotic supplements are more than die-off. I believe that some people can actually be infected with these bacterium and it is something that may be missed. Taking yogurt is better, but kefir in extremely small amounts (tablespoonful) to start, then build up. The cost of probiotic supplements is very high and I am very suspicious about them--similar to the fish oil business. These are not regulated and we could be swallowing bad stuff. That's not a good thing with some immunity-challenged conditions and/or very porous gut membranes, such as we often find with mthfr. Be cautious!
I second that, but would point out that for those who can tolerate probiotics, yogurt and the pills are TRANSIENT bacteria and cannot colonise. Only Kefir (and not the corporate kind) colonises. Avoid Kefirs FOS and other prebiotic sweeteners as they make a lot of people feel bad. There are people on other threads replacing severely damaged microbiomes with raw kefir colonics to amazing effect...
Me, too. An itchy rash that is probably a histamine reaction to whatever die-off or pathogenic yeast flare may be going on with the influx of good bacteria. My rash is usually gone the next day after a lot of water. But everyone must judge her own capacity. Probably less is more is my mistake!
I too think there is some some danger to taking a probiotic. Even if the risk is small, it's still a risk. I never had IBS symptoms until after the whole resistant starch + probiotic craze. At first it was helpful, then later I got sick when starting a new probiotic. Even if it was just a coincidence, I still blame the probiotics for my current IBS situation. I never had this issue in my life, even after CFS. I swear it's like it created a problem to which it is said to be able to fix.