Good question -- and the answer might not be what you expect. First, here are a few basic facts about heartburn, which has nothing to do with the heart. Heartburn is a burning discomfort from the chest area up to the throat. It can happen when stomach acid refluxes, or flows up, through a valve called the lower esophageal sphincter and irritates the esophagus. Certain foods can trigger heartburn, but you may have a little more food freedom than you think, if you consider the pointers in this slideshow.