Brewer’s Yeast for Dogs: The Good and The Bad

If you’ve ever taken the time to study the ingredients listed on dog food labels, odds are you’ve come across brewer’s dried yeast. And if you have, you’ve probably asked yourself, why on earth is there brewer’s anything in my dog’s food!?

I’m here to tell you this common ingredient is nothing to panic about. In fact, brewer’s dried yeast in dog food is typically a very good thing. But, as with any ingredient that goes into your dog’s diet, you should understand what it is and why it’s there.

That’s why we’re going to take a closer look at brewer’s dried yeast. Below, we’ll talk about what it is, why it’s added to dog food, and what the benefits and risks of this common food supplement are.

What Is Brewer’s Yeast?

Brewer’s dried yeast—or brewer’s yeast, as it is more commonly known in the human supplement world—is a byproduct of the beer-making process. 

When brewing beer, brewers use Saccharomyces yeast species, most commonly Saccharomyces cerevisiae, to break down the sugar in grains and turn it into alcohol. As the fermenting process finishes, these yeast are filtered out. This by-product is then cleaned and pasteurized to be sold as a supplement and animal feed additive. 

But, unlike many other byproducts that get sold to pet food manufacturers, this one is actually good for your dog. More on that in a minute.

Brewer’s yeast is different from other common yeast products sold as supplements and for food production. Unlike baker’s yeast, most brewer’s yeast products contained “killed” yeast. This means there is no chance that the yeast can reproduce or cause yeast infections in the body.

Brewer’s yeast should also not be confused with nutritional yeast. While brewer’s yeast is grown on malted barley and other grains, nutritional yeast is grown on sugar or beet molasses. Because nutritional yeast is grown specifically to be harvested as a supplement, it is often grown with added nutrients and has a much more palatable flavor.

Why Is Brewer’s Dried Yeast Added to Dog Food?

Like many other byproducts from the food industry, brewer’s yeast is added to dog food primarily to provide a cheap source of protein.

Brewer’s yeast is over 50% protein by mass. Unlike protein from plant sources, this macronutrient is relatively bioavailable to a dog’s digestive tract, which makes it a better filler protein than peas, legumes, or grains.

But protein isn’t the only thing brewer’s dried yeast provides. This supplement is also incredibly nutrient-dense. It supplies a long list of essential amino acids, vitamins, and minerals. Compared to synthetic nutrients that are often added to dog food to bring it up to AAFCO standards, the nutrients in brewer’s yeast are more readily absorbed and used by the body.

In fact, the cofactors present in brewer’s yeast have been proven necessary for the body to utilize important B vitamins. Multiple studies have shown that dogs with diseases stemming from B vitamin deficiency will not recover when given synthetic B vitamins. But when given natural brewer’s yeast, these dogs quickly get back to full health. 

Given how cheap and incredibly nutritious this product is, it’s no wonder so many dog food companies utilize it in their recipes.

The Benefits of Brewer’s Yeast

There are clear benefits to adding brewer’s yeast to dog food if you are a dog food manufacturer. But there are also plenty of good reasons to add this supplement to your dog’s food as an owner.

Not only is it packed with essential nutrients, but it helps support many systems throughout the body, can help repel pests, and has proven benefits for dogs with certain chronic diseases.

Highly Nutritious

Brewer’s dried yeast contains a long list of nutrients that are not readily available in most foods.
It’s a rich source of protein, as well as:

• Chromium
• Iron
• Magnesium
• Potassium
• Selenium
• Zinc

Uniquely, brewer’s yeast is also loaded with many B vitamins, including:

• Biotin
• Folic acid
• Niacin
• Pantothenic acid 
• Pyridoxine 
• Riboflavin
• Thiamine 

Brewer’s yeast also contains fifteen amino acids in high amounts, including the ten essential amino acids dogs must get in their diet.

It is worth noting that despite all the B vitamins present in brewer’s yeast, it does not contain any vitamin B12. This vitamin is vital for making DNA and keeping your cells healthy. Luckily, B12 is readily available in meat and eggs and dogs fed a quality diet rarely suffer from vitamin B12 deficiency. 

When choosing a brewer’s yeast supplement for your dog, be sure to pick a product that only includes brewer’s yeast and other natural ingredients. Some pet supplements are “fortified” with synthetic nutrients, which is completely unnecessary since pure, quality brewer’s yeast is already packed with natural nutrients that are much better absorbed by the body.

Support Healthy Skin and Coat

All those B vitamins in brewer’s yeast make it a powerful supplement for skin and coat health. It has been used for decades by show dog owners and working dogs to help reduce dry skin, build a shinier coat, and strengthen skin to reduce injury in the field. 

Brewer’s yeast also contains a number of bioactive peptides that have been studied in the cosmetics industry to help reduce signs of aging and support healthier skin. There is even some evidence that these peptides can protect against UV damage to skin cells and prevent oxidative damage from free radicals. 

These peptides have also been shown to stimulate collagen synthesis. This, along with brewer’s yeast’s antioxidant properties, makes it a wonderful supplement to help with wound healing. 

Helps Repel Fleas and Ticks

Brewer’s yeast is also widely recognized as an effective natural treatment for fleas and ticks. How this supplement helps to repel these pests is not yet well understood.

Most likely, the same beneficial components that help to improve skin and coat health work to keep biting pests away. Healthy skin is less penetrable to the bites of these tiny insects, which makes it harder for them to feed.

Additionally, brewer’s yeast contains sulfur compounds, a known irritant to many bloodsucking pests. Dogs who ingest brewer’s yeast may have a faint sulfur scent that keeps these bugs away. Many brewer’s yeast supplements made to fight fleas, ticks, and mosquitos contain added garlic, which also likely helps to create an odor that these pests avoid.

Scientific study into the use of brewer’s yeast for this purpose has had mixed results. The best conclusion that can be drawn is that this supplement is highly effective for repelling topical pests for some dogs, but not all.

Supports Gut Health

One aspect of brewer’s yeast that has been well-studied is its ability to help support gut health. It does this in a number of ways. 

While the process is not well understood, researchers have proven that brewer’s yeast increases the enzyme content of the stomach. This helps the gut more thoroughly digest food and can help relieve diarrhea. Interestingly, this increase in enzymes is also associated with a lower susceptibility to viruses. 

Research has also shown that brewer’s yeast may reduce gut permeability. When the gut becomes inflamed due to food intolerances, gut imbalance, and other issues, gaps form between intestinal epithelial cells. This allows large particles of food, bacteria, and other debris to enter the bloodstream, causing immune overreaction and inflammation throughout the body.

Known as leaky gut syndrome, this issue is incredibly common in dogs and is often the root of chronic allergies. Brewer’s yeast has been shown to reduce gaps in the intestines to help prevent leaky gut syndrome. This makes it an effective treatment to reduce allergy symptoms in many dogs.

In human studies, brewer’s yeast has been shown to improve the symptoms of patients with irritable bowel syndrome. Its ability to increase enzyme production, reduce gut permeability, and support a healthy gut biome, all likely contribute to this phenomenon. This supplement would likely have a similar beneficial effect on dogs with IBS. 

Support Liver Function & Cardiovascular Health

In humans, brewer’s yeast has been found to reduce hypertension. And in mouse models, it has been shown to lower blood concentrations of bad cholesterol and triglycerides. High levels of both of these substances are associated with a higher risk of heart attack and stroke.

High cholesterol also hurts liver health. This fatty substance is stored in the liver and accelerates the damage caused by fatty liver disease. Mice fed a diet that included brewer’s yeast had fewer cholesterol deposits in their livers than mice fed a traditional diet. While fatty liver disease is less common in dogs, it is a common problem in cats, which may also benefit from brewer’s yeast supplementation.

Improves Immune Health

As dogs age, their immune system begins to show more signs of dysfunction. One potential solution that has been well-researched is supplementation with brewer’s yeast. 

In mouse studies, aging animals that received food enhanced with brewer’s yeast showed increased numbers of leukocytes and other important immune cells. They also showed improved marks for immune performance. And all this happened after just one month of supplementation. 

This effect combined with brewer’s yeast’s high B vitamin content and its ability to help neutralize viruses in the gut, makes it a valuable tool for improving immune system function in dogs.

Supports the Metabolic System

Non-debittered brewer’s yeast is naturally high in chromium. 

This mineral enhances the metabolic action of insulin to keep blood sugar within normal ranges. Chromium supplementation can also help increase weight loss and increase muscle mass. This combined with its ability to lower cholesterol makes it a valuable supplement for dogs suffering from obesity or metabolic disorders. 

While the results of chromium supplementation on blood sugar levels in dogs with diabetes are not nearly as impressive as those seen in humans with type 2 diabetes, this supplement still has the potential to support overall health in these dogs.

Is Brewer’s Dried Yeast Safe for Dogs?

Brewer’s yeast is generally considered a very safe supplement for humans and dogs. However, there are some side effects and risks owners should be aware of.

The most common side effect associated with brewer’s yeast supplementation is excess gas. This is most likely to occur in larger dogs receiving a supplemental dose of the product. For smaller dogs, who require smaller doses, and dogs eating food enhanced with brewer’s yeast, gassiness is rarely an issue.

Ounce for ounce, brewer’s yeast is fairly high in calories, which should be considered when adding this to your dog’s meal. For older dogs and those prone to weight gain, it’s a good idea to lower their food serving slightly to account for these extra calories. 

The only real dangers of brewer’s yeast for dogs apply to those on certain medications. This supplement is known to interact with some anti-anxiety medications and some antidepressants. The largest issue lies with monoamine oxidase inhibitors. Because brewer’s yeast contains a large amount of tyramine, it has the potential to interact with these drugs and cause a hypertensive event. 

Brewer’s yeast allergies in dogs are rare but not unheard of. If your dog develops any reaction to this supplement or to brewer’s dried yeast in dog food, it’s best to avoid these products.

Incorporating Brewer’s Dried Yeast into Your Dog’s Diet

Because of its wide array of benefits and high nutritional value, using brewer’s yeast as a dog supplement is a great idea. And, because most dogs find it palatable, it’s fairly easy to add to their diet. 

Brewer’s dried yeast used in commercial dog food recipes is generally not included in amounts high enough to elicit the effects described above. For dogs on these diets, adding additional brewer’s yeast is generally a good idea. If you feed a raw or home-prepared diet, or if your dog’s commercial food does not contain brewer’s yeast, supplementing with it is even more important. 

The typical daily dose of brewer’s yeast for dogs is ½ tsp per 10 to 15 pounds of body weight.

When first introducing your dog to brewer’s yeast, it’s a good idea to start with a low dose and slowly increase it over the course of a week to give their stomach time to adjust. This is especially helpful for large dogs who need a large dose.

If your dog is on any medications or has any medical conditions, it’s a good idea to talk to your vet before starting any new supplement.

Brewer’s yeast has a lot of proven benefits for humans and dogs. It is loaded with vitamins, minerals, amino acids, and antioxidants. The unique combinations of nutrients and compounds in it help support the skin, gut, liver, heart, immune system, and metabolic system. 

By slowly introducing this supplement to your dog’s diet and feeding it consistently, you can ensure they get all the good that brewer’s yeast has to offer without any of the bad.

Sources

A scientific review: the role of chromium in insulin resistance. (2004). PubMed. 

Brewer’s yeast supplementation enhances immune response of aged mice. (2015, June 1). PubMed. 

Elfenbein, H., DVM. (2022). Brewer’s Yeast for Dogs: Understanding the benefits and risks. PetMD. 

Frost, D. V., & Dann, F. P. (1944). Unidentified Factor(s) in Yeast and Liver Essential to Cure of Achromotrichia in Dogs on Synthetic Diets. The Journal of Nutrition, 27(5), 355–362. 

Oliveira, A. S., Ferreira, C., Pereira, J. O., Pintado, M., & Carvalho, A. P. (2022). Spent brewer’s yeast (Saccharomyces cerevisiae) as a potential source of bioactive peptides: An overview. International Journal of Biological Macromolecules, 208, 1116–1126. 

Rummell, L. M., Steele, M., Templeman, J. R., Yohe, T., Akhtar, N., Lambie, J. G., Singh, P., Asquith, T., Verbrugghe, A., Pearson, W., & Shoveller, A. K. (2022). A proof of principle study investigating the effects of supplemental concentrated brewer’s yeast on markers of gut permeability, inflammation, and fecal metabolites in healthy non-challenged adult sled dogs. Journal of Animal Science, 100(11). 

Smith, S. G., Curry, R., & Hawfield, H. (1943). Vitamin B6 Deficiency Anemia in the Dog. Science, 98(2554), 520–522. Waszkiewicz-Robak, B., & Bartnikowska, E. (2009). Effects of spent brewer’s yeast and biological β-glucans on selected parameters of lipid metabolism in blood and liver in rats. Journal of Animal and Feed Sciences, 18(4), 699–708. 

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Sara Seitz worked in the pet industry for over a decade. In addition to being a certified dog trainer, Sara gained experience working as the general manager of a dog daycare and boarding facility, as the creator and manager of a pet sitting company, as a groomer, and as a dog behavior evaluator. She also has a bachelors in animal behavior from CSU. Currently, Sara works as a freelance writer specializing in blog, article and content writing.