Although I have very bad digestions when I tried betaine or digestive bitters i get some heartburn. I think my digestive problems come from candida, their toxins, lack of lacto/bifido bacteria, etc... because I also tried digestive enzymes with no results.
Candida can contribute to heartburn, but this still goes back to a lack of stomach acid. All of the areas of the body where Candida normally resides are acidic because the acids help to control the Candida. Stomach acid is no different. When the stomach is sufficiently acidic Candida cannot grow in the stomach. When stomach acid levels decline or are neutralized with antacids, acid blockers, alkaline waters, calcium or magnesium hydroxide, baking soda, etc. Candida can grow in the stomach due to the alkalinity that promotes Candida growth and aggressiveness. The Candida increases fermentation in the stomach leading to gas formation. As the gas escapes rapidly up the esophagus traces of acid are carried with it leading to the heartburn.