Here is an interesting evidence based article with some good information about sourdough, what it is, science behind it and how to make it.
The article, written by Alina Petre starts out saying:
“Sourdough relies on a mix of wild yeast and lactic acid bacteria, rather than baker’s yeast, to leaven the dough. It’s richer in nutrients, less likely to spike your blood sugar, contains lower amounts of gluten, and is generally easier to digest than bread made with baker’s yeast.”