Brewers yeast supplements are suitable for dogs and recommended by some vets for keeping fleas under control, improving dogs' immune systems, enhancing canine health and improving the look of the dogs' coats. Brewers yeast is high in Omega fatty acids, antioxidants and B vitamins.
A daily supplement of brewers yeast is said to keep away biting insects, including fleas, ticks, biting flies and mosquitoes. It is not clear why brewers yeast supplements have this effect on animals. It is thought that the brewers yeast causes an odor to be emitted that keeps the pests away or that it makes the blood taste bad.