Sourdough bread has a distinct flavor that many people love. It’s also often thought to be healthier than regular white bread because it is made without chemical leavening agents like baking powder or bromured yeast. The long soaking of grains for sourdough makes the starch easier on our bodies to digest and eliminates some of the phytates that would otherwise make it hard to break down. In addition, the natural yeast predigests some of the starch for us, so the body absorbs the nutrients more easily.
In large amounts, however, sourdough can cause problems for dogs. Those who have wheat or gluten allergies, sensitivities, or intolerances should avoid eating it at all, as should dogs who are overweight. Even small pieces of sourdough can contribute to bloating and stomach discomfort in dogs.
The biggest problem is if a dog eats unbaked sourdough bread or dough. The warm, moist environment of their stomach causes the dough to expand and ferment, producing toxic levels of ethanol. This can cause a dangerous drop in blood sugar, blood pressure, and body temperature, as well as death.
Cooked sourdough bread can be fine for most dogs in small quantities, as long as it isn’t a staple of their diets and does not contain ingredients that are harmful to them like chocolate, raisins, or onions. A few slices of sourdough can be nice as an occasional treat, but they should not be the mainstay of any dog’s diet because it does not provide them with enough protein and essential nutrients.