What are the benefits of using brewers yeast for fleas in cats?

Brewer's yeast can help repel fleas in cats due to its high content of B vitamins, particularly thiamine. When ingested by cats, the yeast produces a scent that is unappealing to fleas, making the cat less attractive to them. Additionally, some believe that the taste of brewer's yeast on the cat's skin can act as a natural deterrent to fleas.