Yes.

Yes. When labs do studies and want to grow yeasts, they often use a broth that contains sterilized yeast cells (ie, dead yeast cells) and add live yeast to that, and get much growth. The dead yeast yields the amino acids and other nutrients the live yeast needs in order to grow.

That said, eating a tiny amount of yeast would be better than, say, eating a large amount of sugar, because obviously Sugar also feeds yeast. But if all you are asking is if dead yeast in bread can feed living yeast in your body, yes, it can.

And all bets are off if you have an actual allergy to eating yeast, even small amounts - in that case then small amounts can be worse than they would to a candida sufferer who isn't actually allergic to eating small amounts of dead yeast. Confusing, I know. trial and error, watching symptoms, is often the only way to know.