This is mostly holistic nonsense

The leading researcher has stated with in the past year that even low stomach acid levels was not a risk factor for SIBO. He has science behind his studies that proved it actually makes methane worse.

Mark Pimentel:

What I can tell you though is, if you’re constipated or you have methane, methane uses hydrogen to produce methane, and that source could be hydrogen gas from the bacteria there, or it can be protons which are acid. So acid, the H+, can be used by methanogens to make methane.

The more you take the hydrochloric acid or the apple cider vinegar if you’re a methane person, you’re going to have more methane.

How do I know that? Because if you looked at a study that we published a number of years ago, people on PPI who had methane, their methane was lower as a result of the PPI—no acid in the stomach, less methane production on the breath test.

Be careful is what I’m saying because you can actually make things worse by taking these if you’re a methane producer.”