Brewer’s yeast is quite frequently included in dog foods because of its high Vitamin B content. It also gives your puppy or dog some important trace elements like selenium and zinc, which are good for his or her skin. The yeast itself is a natural organism — just like baking yeast — and it can play a helpful role in keeping your pup’s skin and eyes healthy.
It’s generally considered a healthy ingredient to include in kibble, and may even contribute to keeping away fleas, but that hasn’t been researched in very great depth recently.