What would cause heartburn in marinara sauce?
Tomatoes relax the lower esophageal sphincter, a muscle at the top of the stomach that contracts to keep stomach contents from going back up the esophagus. The more concentrated the sauce the more the relaxing effect. Alcohol does this as well, and over-eating can lead to the LES muscle being unable to overcome the pressure. So if you had a big portion of pizza with extra strong tomato sauce and a few beers or glasses of wine it's a triple-whammy.