What are the benefits of using brewers yeast for fleas on pets?

Brewer's yeast can help repel fleas on pets due to its high levels of B vitamins, particularly thiamine. When ingested by pets, the yeast produces a scent that is unappealing to fleas, making the pet less attractive to them. Additionally, the yeast can improve the overall health of the pet's skin and coat, making it less hospitable for fleas to thrive.