1. Chemical Preservatives
Preservatives like BHT (butylated hydroxytoluene) and BHA (butylated hydroxyanisole) are synthetic preservatives commonly used in processed foods, skin care products, and pet foods. They’re deemed reasonably safe by the FDA, but the National Toxicology Program has stated that BHA is likely a human carcinogen, and BHT has been linked to both higher and lower cancer risks in various animal trials. According to Berkeley Wellness, the bottom line is that no one really knows how these chemicals might affect human and pet health, and they advise limiting consumption as much as possible. Avoiding these ingredients is especially important for pets, because, unlike humans, they typically eat the same food at every meal, meaning they’ll likely have a higher exposure rate to these chemicals than you do.
Menadione is also known as vitamin K3, a synthetic version of vitamin K—you might see it on pet food labels as menadione sodium bisulfate, menadione sodium bisulfite, or menadione dimethylpyrimidinol bisulfite. Vitamin K, which is typically found in leafy greens, helps the body form blood clots. But dogs and cats actually need very little vitamin K to stay healthy, according to The Dog Food Advisor. Most of what they need in terms of K is produced by the animals’ gut bacteria. Critics argue that there’s no good reason to include menadione in pet food, especially because there’s some evidence that it causes liver toxicity and damage to cell membranes, according to reports by The Dog Food Advisor. It has also been banned from use in human food since 1963.
Related: Is It OK To Feed Your Dog Fruits And Vegetables?
3. Meat-Byproduct Meals
Brace yourself—this isn’t going to be pretty. When you see animal byproducts on the list of ingredients in pet food, it basically means they’re getting all the refuse from the human food industry, like organs, blood, bones, fatty tissue, and beaks. While that sounds absolutely disgusting to you and me, your pet would probably not object to any of those ingredients, and it’s generally OK to give your pets foods that contain small amounts of byproducts. When a feral cat hunts a bird, for example, she’ll eat just about everything but the wing feathers. But note that “chicken byproduct meal” is a slightly different and more questionable product.
According to PetMD, when the word “byproduct” is followed by “meal,” it indicates that the meat leftovers were rendered, or cooked for several hours to kill off bacteria, viruses, and parasites. That may not sound so bad, but it could also be a sign that, in addition to the ingredients mentioned above, the meal may also contain more questionable meat-industry waste, such as (very) out-of-date supermarket meat, restaurant grease, and diseased or disabled livestock. (Contrary to popular belief, however, pet food cannot contain hoofs, horns, feces, or roadkill.)
That said, “chicken meal” can be perfectly safe if you buy a high quality product. The Dog Food Project adds that you should only buy brands that list specific types of meat on the ingredient list, like Castor and Pollux Organix. For example, look for “chicken” or “chicken meal,” not “poultry” or “poultry meal,” and especially not the deliberately vague “animal meal”—it’s anyone’s guess what’s in that last one.
4. Corn Products
Dry kibble can be loaded with corn byproducts, which are used as a cheap filler to bulk up treats. The kind of corn we’re talking about is feed corn, or more accurately ground up feed corn scraps, which you’ll often see as the ingredient “corn gluten” on labels. While corn isn’t necessarily bad for cats and dogs, you don’t want to purchase foods where corn is the main ingredient or protein source because that’s a sign the product is nutritionally lacking, according to Sabine Contreras, a canine care and nutrition consultant with The Dog Food Project. Instead, look for brands whose main ingredients are specific types of meat protein, such as chicken or tuna.
Related: How To Grow Corn
5. Any Kind Of Sweetener
It’s a no-brainer that sugar is just as bad for your pets as it is for you. According to The Dog Food Project, you’re more likely to see sweeteners in cheap, poor quality foods—and your pets can get addicted to them just like you do. Leave products that contain sugar, corn syrup, cane molasses, fructose, glucose, and ammoniated glycyrrhizin (a licorice extract) on the shelf. Natural sweeteners like honey and blackstrap molasses are fine in small amounts in special treats, but they shouldn’t be a part of every meal.