Different answer for this:
Using yogurt as an example, it is milk that has been fermented by microorganisms. It contains two sources of value to you as a food:
- The proteins in the milk it's made from, MINUS the lactose sugar that the microorganisms have pre-digested for you to the acids that curdle (denature) the milk proteins and add the tangy flavor.
- The microorganisms themselves, which are ALIVE and can help repopulate your gut bacteria and yeasts (your microbiome) with good bugs.
When you cook with yogurt (or any other fermented/cultured product that contains LIVE microorganisms that are part of the value of the product as a probiotic), you KILL the microorganisms, which therefore cannot reproduce in your gut anymore - they''re dead, Jim. The yogurt protein is still good for you (that's just a source of amino acids, once you eat it) and the elimination of lactose by the bacteria in the process of culturing the milk into yogurt is still helpful for making the milk proteins less problematic to ingest (because they are now lactose-reduced or -free), but if the good bugs are cooked, they do not have any additional value as a probiotic - which requires that the bugs be alive.
