What are the worst ingredients in dog treats?

April 23, 2021

From rawhides to biscuits, jerky to chews. There are hundreds of dog treats on the market, but they are not all created equal. Treats should be an extra snack or reward for your dog but that shouldn’t mean that you sacrifice quality ingredients for doggy junk food.

From rawhides to biscuits, jerky to chews. There are hundreds of dog treats on the market, but they are not all created equal. Treats should be an extra snack or reward for your dog but that shouldn’t mean that you sacrifice quality ingredients for doggy junk food. 

Unfortunately, many of the top treats on the market are made with less than desirable ingredients. Just because a product is classified as a “treat”, it does not mean that manufacturers should be able to use cheap, filler ingredients which may cause health problems in dogs long term. A treat should be full of quality ingredients which supply your dog with some nutritional value. For that reason, here are 5 ingredients of the the worst ingredients in dog treats and 5 of the best:

A Golden Retriever dog holding her dog biscuit in mouth closing eyes

Bad: Wheat flour and cornstarch

What are wheat flour and cornstarch and why are they used? Wheat flour and cornstarch are probably not unfamiliar terms. It is the ground, dehulled part of the wheat or corn cereal grain. Flour is made up of mostly starch carbohydrates, since the fibrous hull of the grain has been removed. Flour provides the structure in baked goods. Wheat flour contains proteins that interact with each other when mixed with water, forming gluten. It is this elastic gluten framework that provides cohesiveness and structure to a baked or extruded product. 

Why is this a bad ingredient? Are we baking bread? No. Then why are treat manufacturers using wheat four and cornstarch in their dog treats? The reason is that they are cheap ingredients, which are widely available. Wheat flour and cornstarch are full of highly available sugar, which puts dogs at risk of developing diabetes. When the flour is consumed, the high starch content is broken down into a sugar called glucose. The breakdown of glucose is initiated by a hormone in the body called insulin and is then stored in the liver. The continuous ingestion of sugars in the wheat flour and cornstarch cause a spike in blood sugar and insulin production. 

Over time, these spikes in blood sugar begin to overwhelm the insulin mechanism, putting dogs at risk for developing diabetes. It is a mystery why manufacturers continue to use wheat flour or cornstarch when there are so many healthier carbohydrate alternatives like the following good ingredients.

Good: Grain-free flours

Grain-free flours are a superior alternative to wheat flour since they contain a much lower ratio of available sugars. Examples of grain-free flours include ingredients like pea flour, chickpea flour or lentil flour. These ingredients are less likely to spike an insulin response because they contain more resistant starch, which is not as rapidly broken down into glucose. 

Grain-free flours also contain a higher proportion of protein than grain flours, which is an added bonus. Compared to grains like corn or rice, which are approximately 3% and 2.7% protein respectively, peas specifically have upwards of 5% protein!

Bad: Whole bones

What are whole bone products and why are they used? These usually fall under the “chew” or “dental” category of treats. Even though many raw food supporters promote feeding bones to dogs, they are actually considered a by-product from the rendering of human meat products. Whole bones come from many different types of animals but the most common are usually beef bones.

Why are whole bones a bad ingredient? The biggest reason is that bones can very easily cause dental fractures and tooth breakages. These products are also a choking hazard as dogs can accidentally (or some one purpose) swallow them whole. Antlers and hooves also fall under the whole bone category and may pose the same risks. 

If you are concerned about your dog’s dental health, the best method is to brush their teeth using doggy safe toothpaste. Alternatively, if you want a chew to keep your dog busy, try filling a kong or food toy with healthy ingredients like bone broth, greek yogurt or natural peanut butter. Freeze the kong overnight and it will provide your dog with an excellent mental challenge and a tasty treat!

Chocolate labrador puppy lying and chewing a dog bone

Good: Omega 3’s

Omega 3 fatty acids can be found in a variety of ingredients like flax seed, salmon, fish oil, hemp hearts, and chia seeds. Omega 3 fatty acids come from a class of polyunsaturated lipids that are broken down into 3 different classes; alpha linoleic acid (ALA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).

Omega 3 fatty acids are extremely important for metabolism and daily physiological processes. Most notably omega 3’s are involved with lowering inflammation and playing a role in the structure of cell membranes. Studies have shown that omega 3 consumption may actually be linked to decreases in cardiovascular disease in humans. This is most likely due to its antioxidant properties. Other studies have shown the potential of omega 3s to lower the risk of diabetes, improve cognitive function, accelerate weight loss and improve nerve function. Click here if you’d like to learn more about the potential health benefits of omega 3s!

Bad: By-product meals

What are by-product meals and why are they used? A by-product meal is essentially a cheap alternative to using actual meat in treats. By-product meals are the ground, dried leftovers from the meat rendering plants. These by-product meals include things like bones, cartilage, feathers and viscera.

Why are by-product meals bad? Body parts found in by-product meals like ones, cartilage, feathers and viscera aren’t nearly as digestible to dogs as whole meat meals like chicken or fish meal. It is often cheaper to use these meat meals and allows pet food companies to cut corners and save money, while sacrificing a quality product.

Good: Fruits & veggies

It probably comes as no surprise that fruits and veggies are healthy ingredients.They provide a great boost of vitamins, minerals, fibre and antioxidants. Vegetables aren’t quite as palatable to dogs as fruits are so they are usually included lower in the ingredient list. Fruits however add a little bit of sweetness and can actually become the main flavour of a product. Just be aware of which fruits and veggies are dog safe!

A 2005 statistical study even suggests that the simple incorporation of fresh vegetables into your dog’s daily diet may be very beneficial in the battle against transitional cell carcinoma (TCC), a type of urinary cancer. Data showed that dogs which consumed vegetables, specifically yellow-orange and green vegetables, at least 3 times per week were associated with a 70% reduced risk of developing cancer. It was hypothesized that because these vegetables contain compounds like carotenoids, ascorbate, tocopherols, and selenium, they act in an anticarcinogenic manner and protect the dog from developing TCC.

Black and white long haired dog with bunch of carrots in mouth.

Bad: Artificial colours and flavours

What are artificial colours and flavours and why are they used? Colours and flavours added to pet food are usually to draw in the human consumers rather than dogs. Chemicals are added to treats like Red 40, Yellow 5, Blue 1, Yellow 6, Caramel Color, Smoke Flavor, and Salmon flavour, to boost the apparent palatability of a product.

Why are artificial colours and flavours bad? Dogs and cats do not care what color their kibbles are or if their food smells like “backyard bbq”. Instead, why not just use whole, quality ingredients and let those flavours speak for themselves? These added colors and palatants can even be toxic to pets. Scientific studies have even shown that some artificial ingredients, like red and yellow dyes, can even be carcinogenic and cause cancer. 

A study by Paul et al. found that after feeding the transforming dyes Blue 2, Green 2024, Red 4 to hamsters, the incidence of tumors and/or mortality increased in at least one strain of hamster, but none of the non‐transforming dyes which included Blue 1, Red 3, Yellow 5, Yellow 6 and Green 3, induced a significant increase in tumor incidence or animal mortality.

Food dyes and flavours have also been shown to trigger allergic reactions in dogs. A study by Ermel et al. found that “direct mucosal challenge with food extracts confirmed the clinical and immunologic evidence of food allergy in immunized dogs”.

Good: Quality meat ingredients

It’s no surprise that dogs love meat. They are obligate carnivores afterall! However not all meat is created equal. As mentioned above, by-product meals and meat-mix meals should be avoided. Instead look for whole meat proteins or whole-protein meals. Ingredients like salmon meal, chicken, lamb meal, beef liver, etc. are a great source of protein and energy. These ingredients also make treats that much tastier to dogs and are more digestible than by-product meals.

Dog sitting behind the kitchen table and looking at raw chicken meat Dog sitting behind the kitchen table and looking at raw chicken sitting in a blue bowl on a table

Bad: BHA, BHT and ethoxyquin

What are BHA, BHT and ethoxyquin and why are they used? BHA, BHT and ethoxyquin are chemical preservatives added to treats to keep them from going rancid. While not used as frequently in whole diets, these preservatives can still be found quite frequently in big name treats. Preservatives are required in a lot of food that is kept at room temperature and not all preservatives are bad. Ultimately, it is better to use safe preservatives in pet food than having it go rancid and risk having microbial contamination. However, there are some preservatives like BHA, BHT and ethoxyquin that should be avoided and could be very dangerous to pets.

Why are BHA, BHT and ethoxyquin bad? Probably the most notable reason why BHA and BHT are bad news is because they have been classified as carcinogenic by the US FDA. Ethoxyquin on the other hand, may potentially cause liver and kidney damage, immunodeficiency, blindness and leukemia. 

If these preservatives are as dangerous as studies say then why are they still being used? Because they are effective preservatives. Some companies are willing to cut corners in other areas of health to ensure that their product is shelf stable for as long as possible. Other preservatives like Vitamin E and citric acid could be used instead to keep treats from spoiling.

Good: Antioxidants

Antioxidants is a big buzz word in the nutrition community, but what actually are they and what do they do for dogs? Antioxidants protect from inflammation and oxidative stress caused by free radicals. Inflammation and oxidative stress are responsible for negative reactions like swelling, joint pain and redness. There are many different foods that contain antioxidants which just a few being: leafy vegetables, berries, carrots, hemp hearts, and some spices like turmeric and cinnamon.


Bhatt DL, Steg PG, Miller M, Brinton EA, Jacobson TA, Ketchum SB, Doyle RT, Juliano RA, Jiao L, Granowitz C, Tardif JC, Ballantyne CM (January 3, 2019). "Cardiovascular Risk Reduction with Icosapent Ethyl for Hypertriglyceridemia". New England Journal of Medicine. 380: 11–22. 

Grey A, Bolland M (March 2014). "Clinical trial evidence and use of fish oil supplements". JAMA Internal Medicine. 174 (3): 460–2.

Hooper L, Thompson RL, Harrison RA, Summerbell CD, Ness AR, Moore HJ, et al. (April 2006). "Risks and benefits of omega 3 fats for mortality, cardiovascular disease, and cancer: systematic review". BMJ. 332 (7544): 752–60.

Pan A, Chen M, Chowdhury R, et al. (December 2012). "α-Linolenic acid and risk of cardiovascular disease: a systematic review and meta-analysis". Am. J. Clin. Nutr. (Systematic review). 96 (6): 1262–73. doi:10.3945/ajcn.112.044040. PMC 3497923. PMID 23076616.

Swanson, Danielle, Robert Block, and Shaker A. Mousa. "Omega-3 fatty acids EPA and DHA: health benefits throughout life." Advances in nutrition 3, no. 1 (2012): 1-7

Jennifer L. Adolphe, Murray D. Drew, Qian Huang, Tawni I. Silver, Lynn P. Weber. “Postprandial impairment of flow-mediated dilation and elevated methylglyoxal after simple but not complex carbohydrate consumption in dogs” (2012). Nutrition Research. 32:4 pg278-284. https://doi.org/10.1016/j.nutres.2012.03.002. https://www.sciencedirect.com/science/article/pii/S0271531712000450 

Adolphe, J. L., M. D. Drew, T. I. Silver, J. Fouhse, H. Childs, and L. P. Weber. "Effect of an extruded pea or rice diet on postprandial insulin and cardiovascular responses in dogs." Journal of animal physiology and animal nutrition 99, no. 4 (2015): 767-776.

Bosch, Guido, Adronie Verbrugghe, Myriam Hesta, Jens J. Holst, Antonius FB van der Poel, Geert PJ Janssens, and Wouter H. Hendriks. "The effects of dietary fibre type on satiety-related hormones and voluntary food intake in dogs." British Journal of Nutrition 102, no. 2 (2009): 318-325.

Teixeira, Fabio A., Daniela P. Machado, Juliana T. Jeremias, Mariana R. Queiroz, Cristiana FF Pontieri, and Marcio A. Brunetto. "Effects of pea with barley and less-processed maize on glycaemic control in diabetic dogs." British Journal of Nutrition 120, no. 7 (2018): 777-786.

Raghavan, Malathi, Deborah W. Knapp, Patty L. Bonney, Marcia H. Dawson, and Lawrence T. Glickman. "Evaluation of the effect of dietary vegetable consumption on reducing risk of transitional cell carcinoma of the urinary bladder in Scottish Terriers." Journal of the American Veterinary Medical Association 227, no. 1 (2005): 94-100.

Price, Paul J., William A. Suk, Aaron E. Freeman, William T. Lane, Robert L. Peters, Mina Lee Vernon, and Robert J. Huebner. "In vitro and in vivo indications of the carcinogenicity and toxicity of food dyes." International journal of cancer 21, no. 3 (1978): 361-367.

Ermel, Richard W., Martin Kock, Stephen M. Griffey, Gregory A. Reinhart, and Oscar L. Frick. "The atopic dog: a model for food allergy." Laboratory animal science 47, no. 1 (1997): 40-49.

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