Is a Niacin Flush an indicator of a specific bacteria (family) in the gut?

Last Friday I was outside putting in 100′ of fencing under a hot sun. Over the years, I have found that my first “heat exposure” of the summer has often resulted in heat diarrhea. I have long accepted that this was just my body resetting itself for a shift from winter cold to summer heat. How it resets has been a fuzzy question.

This time around I noticed something unusual, for the past many weeks I have had a 100% occurrence of a niacin flush after taking 500 mg of niacin. After the diarrhea, there was no flush. I have recently noticed a similar thing a few months ago: when I started taking Mutaflor, niacin flushes also disappeared and stayed away for months. My inference is that the flush is the result of a specific group of bacteria responding to niacin. If this group of bacteria is suppressed below a certain level, then no niacin flush occurs.

Which bacteria is the cause? Well, this will likely need some heavy PCR testings of flushers versus non-flushers being pushed through some fancy programs.

The flip side is whether this is seen in others, or can be simulated. Can we simulate the effect of flushing out a high percentage of the gut bacteria as happens with diarrhea? There is alternative colon cleanse which is reported to reduce symptoms with some CFS patients, but I have not seen any studies associating it with a change in niacin flush rates.

I am interested in hearing of any change of CFS symptoms (in specific niacin flushes) seen when patients have a colonoscopy. The usual process involves clearing out the colon and with this clearing out there may be a temporal alteration of gut bacteria.

On a similar line, I would be interested in hearing about changes of symptoms when a CFS patient acquires a case of diarrhea — in theory, there should be a lessening of CFS symptoms in some patients.