"Acid foods" refers to foods that have a high level of acidity. These foods typically taste sour or tangy and can include items like lemons, tomatoes, vinegar, and citrus fruits. Full definition
High acid foods can also make any of these conditions worse if you have them already. (med-health.net)
An Omega - 3 fatty acid food supplement might be helpful. (okcpetsmagazine.com)
Baking soda can also be used with acid food ingredients but the amount of a specific ingredient depends on how much acid it contains so the balance is a little more difficult. (foodhero.org)