the scientific study of pet nutrition by veterinary nutrition specialists and experts.

Stop reading your pet food ingredient list!

Stop reading your pet food ingredient list!
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“Stop reading your pet food ingredient list!” This was the advice I gave in my June 4, 2018 post: “A broken heart: Risk of heart disease in boutique or grain-free diets and exotic ingredients.”  I received some criticism for this statement and I shouldn’t have been surprised since our research has shown that ingredient lists are the most common way that pet lovers decide on their pets’ food. Unfortunately, the ingredient list is one of the worst ways to select your pets’ food (to learn more, you can read our post on this – “Why you shouldn’t judge a pet food by its ingredient list”).

To summarize, the ingredient list has legal requirements (for example, ingredients names and being in order of weight) but it’s also used as a powerful form of marketing to pet owners.  Namely, manufacturers include ingredients that will appeal to pet owners but probably don’t provide any nutritional benefit to the pet, such as artichokes, kale, and blueberries. More importantly, the ingredient list doesn’t tell us anything about the quality of the ingredients (the quality of the chicken by-product meal one company uses may be much better quality than that of the de-boned chicken another company uses). It also doesn’t tell us whether the ingredients are used in the right amounts to provide optimal nutrition for pets (as a side note, pet foods containing “human grade” ingredients that may sound more appealing to us, such as “fresh angus beef”, can increase the number of animals that need to be raised to feed humans and pets and have a negative impact on the planet in terms of sustainability). Much more important information on your pet’s food label can help you select what is truly the best food for your pet.

Believe it or not, I do read the ingredient list of pet foods but probably not for the reasons you think. I use the ingredient list to look for red flags that make me avoid that food. Here are a few of the red flags I look for:

1.Questionable ingredients

I often find questionable ingredients that make me doubt whether a product is an optimal food I’ll be comfortable recommending for a dog or cat. Most of the questionable ingredients I find are included primarily for marketing purposes (e.g., apricots, smoked salmon, parsley) and for which there is no evidence of any benefit in pets (and they are often in such tiny quantities that I call them “fairy dust).” While these don’t necessarily make the food unsafe, each extra ingredient means (hopefully) more quality control, time, and expense to ensure that the finished product adheres to the desired nutrient formulation and safety.

Another example of questionable ingredients is cat foods containing flaxseed.  Since cats can’t convert the fatty acids in flaxseed to the beneficial fatty acids found in fish oil, flaxseed has minimal benefits for cats. So, the rationale for including it in cat foods is unclear.

2. Too few ingredients

One of our previous posts explained how to determine from the label if your pet’s food is nutritionally complete and balanced (meaning it has at least the minimum levels of all the required nutrients for each life stage and does not exceed the maximums).  Complete and balanced foods require a specific statement that this was either determined by feeding tests or formulation.  There’s actually a third option for the nutritional adequacy statement: “This product is intended for intermittent or supplemental feeding.”  This statement means that food is not nutritionally complete and balanced and you should not feed this food as a main diet to your pet.  An exception is a veterinary diet designed to manage a medical condition, such as kidney disease.  Some of the veterinary diets are specifically designed to not be complete and balanced to help manage a medical condition.  However, all over-the-counter diets should  have all the nutrients your dog or cat needs to stay healthy so any “intermittent or supplemental” over-the-counter diets should only be fed as an occasional treat (if at all).

 Diets that are not nutritionally complete and balanced should have the “intermittent or supplemental” statement on the label.  However, I have found some pet foods that claim to be complete and balanced but have too few ingredients to make this possible.  For example, I once found a cat food that only contained beef, lamb, and pork lung, kidneys, liver, and meat plus potato starch and fiber, and a form of calcium carbonate.  While  the organs (otherwise known as by-products) are nutritious ingredients, it is highly unlikely that this list of ingredients could provide all the vitamins and minerals a cat needs.  Yet, this food claimed to be complete and balanced for all life stages.  To test this, I submitted this food for analysis by an independent lab for 13 of the more than 40 required nutrients for a cat (a full analysis was too expensive) and found 4 nutrients (31%) were deficient for adults and 6 nutrients (46%) were deficient for kittens.  As a sole diet for an adult or growing cat, these deficiencies could be disastrous!  The bottom line is to be suspicious if an ingredient list doesn’t have many (or any) vitamins and minerals.

One last tip to identify pet foods that might not be nutritionally complete and balanced: a pet food can claim to be “all-natural” or “100% natural” “when every ingredient used to manufacture the product complies” with the natural term as defined by the Association of American Feed Control Officials (AAFCO). Because most vitamins and minerals are synthetic and are important to include in nearly all pet foods, companies can claim “natural with added vitamins, minerals and trace nutrients.” If you see an “all-natural” or “100% natural,” check the nutritional adequacy statement to see if it’s nutritionally complete and balanced (it’s probably not).

3. Exotic ingredients

I’ve also been reading ingredient lists a great deal in recent months because of our investigations on diet-associated dilated cardiomyopathy in dogs (see my original post and update on this issue). Exotic ingredients, such as kangaroo, bison, venison, chickpeas, or lentils are possible factors that are being investigated along with diets from boutique companies and grain-free diets. There are no known health benefits of using these exotic ingredients instead of more typical ingredients, and not as much is known about exotic ingredients’ safety, nutritional effects, bioavailability, and interactions between nutrients so there is greater likelihood of problems. Stick with diets with common, well-studied ingredients and that are made by companies with strong nutritional expertise and rigorous quality control.

What’s a wise consumer to do?

Our dogs and cats rely on us to select the best diets for them with good quality ingredients but just as importantly, they need pet foods with all the essential nutrients in the correct amounts and the optimal forms.  Unfortunately, this information is not found in the ingredient list and you’re more likely to be swayed by the ingredient list’s marketing.  However, I do encourage consumers to read the ingredient list to look for red flags that can help them avoid questionable or potentially harmful ingredients or unbalanced diets.  With this background in hand, consumers can outmatch the marketing and rely on more objective information to select the best food for their pets.


Dr. Freeman is a veterinary nutritionist and a professor at Cummings School of Veterinary Medicine at Tufts University. She is on the cutting-edge of science, with hundreds of articles in prestigious journals, speaking engagements at national and international conferences, and awards for her scientific achievements. However, she also is passionate about providing objective and accurate information on pet nutrition to veterinarians, pet owners, and other animal enthusiasts.

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