Brewer’s Yeast for Cats: What You Need to Know

Brewer’s yeast is a dried, inactive yeast ingredient that may be included in some cat foods or sold as a supplement. When added to cat food, it is typically used to increase the flavor and nutrient content.  

Brewer’s yeast is also available as a stand-alone supplement and combined with other ingredients in a variety of supplement products. 

Brewer’s yeast is generally well tolerated in cats in small amounts if it fits their overall diet plan and your veterinarian agrees.  

However, most cats don’t need it as long as they eat a complete and balanced cat food. If your cat is on a prescription diet, takes medications, or has a medical condition requiring a specific nutrition plan, ask your veterinarian before making any changes or adding a supplement.  

Brewer’s yeast is mainly used to make cat food more palatable. In one study, cats showed a stronger preference for food containing dried yeast. The same study found no significant differences in stool quality or nutrient digestibility in cats fed the diet with yeast.  

In most studies, brewer’s yeast was included in the diet rather than given as a separate pill or powder. Since that was the case, any effects observed may be due to another ingredient in the diet rather than the yeast alone.  

Brewer’s yeast may make some foods more appealing to cats, and it may fit into a well-formulated diet without causing obvious problems in healthy adult cats.  

In terms of health benefits, brewer’s yeast is packed with healthy B vitamins, protein, amino acids, and minerals including selenium, potassium, chromium, zinc, iron, and magnesium.  

Long-term safety data for using brewer’s yeast in cats is lacking. The studies that have been conducted were short-term and in a small population of cats, so they don’t tell us much about prolonged use.  

If your cat vomits, has diarrhea, eats less, or seems off after starting a new food or supplement, stop giving it and call your veterinarian.  

If your veterinarian agrees that brewer’s yeast is a good idea for your cat, choose a cat food that includes it or purchase a vet-approved powder supplement. Treats and supplements should always be fed as a small part of a complete and balanced diet, so use it as an add-on to your cat’s regular food and not as a meal replacement. 

Keep a close eye on your cat any time you start a new supplement or food. Pay close attention to how your cat eats, how their stool looks, whether their weight stays steady, and if they are experiencing any potential side effects.  

If you notice any concerning changes, stop giving the supplement and check in with your veterinarian. 

If your cat eats more brewer’s yeast than intended, call your veterinarian or an emergency hospital for advice, and have the package nearby so you can relay important details about the ingredients and the amount your cat ate. If your cat develops vomiting, diarrhea, or another concerning change, get help promptly.  

Does brewer’s yeast improve skin or coat condition? 

There is no evidence showing that brewer’s yeast improves skin or coat condition in cats. Studies performed in cats were short feeding studies, and did not address skin or coat issues.   

Is brewer’s yeast a probiotic? 

No. Brewer’s yeast is an inactive yeast ingredient, not a live microorganism. One study in cats looked at fecal microbiome diversity and did not find an overall change over 14 days.  

Can I give brewer’s yeast every day? 

Maybe, but only if your veterinarian thinks it’s a good idea. Because treats and supplements should make up only a small part of your cat’s diet, brewer’s yeast should not replace meals. 

What does the evidence show? 

Mostly studies involving brewer’s yeast in cats have been short feeding studies in healthy adult cats. They suggest possible improved palatability. Other possible benefits would be due to the ingredients contained within brewer’s yeast.