I've read gerd/heartburn is often caused by low stomach acid and not too much. Is this true or more of a holistic/natural type point of view?

Not true. GERD is caused by contents in the stomach coming up through the esophagus, which in turn has a poorly understood cause. We think it is probably due to too many random openings of the valve. Certain medications can also cause the valve to open, as can stress, obesity, & problems with the stomach emptying to name a few. Hope this helps!