Picking out the best dog food can be a big challenge. Food manufacturers sometimes pick less than ideal ingredients to cut costs or appeal to humans who don’t necessarily understand a dog’s nutritional needs. There is also a lot of debate about what kind of macronutrient balance is best for dogs and whether grains or other food sources are okay. We can’t give you definitive answers on all that, but we can point out a few ingredients that dog food might have that you should not accept.

Here are eight ingredients in dog food that can cause health problems.

1. Corn Syrup

Corn syrup is used to add sweetness to human and dog foods. However, this simple sugar has no place in a dog’s diet. Dogs do not overly like sweet foods, and there are better sources of calories for them to consume that are more nutritious.

2. Sodium Hexametaphosphate

This salt is found in many foods, human and dog alike. It is used as an emulsifier in most foods, except in dog dental treats where it can be used to strip tartar from teeth. The problem is that high levels of this salt can cause health problems, even heart problems.

3. Ethoxyquin

Developed originally to keep pears fresh, this chemical is now used to keep foods fresh and prevent color loss. It is an antioxidant, but there is evidence that its use in pet food has elevated liver enzymes in pets. This can cause weight loss, liver, kidney and bladder problems. A byproduct of ethoxyquin has been demonstrated to cause damage to pets’ DNA.

4. Nitrates

You can find small amounts of nitrates in treated meats meant for humans and for pets. Sausages, pork, hot dogs and other foods may have nitrates. While in small amounts they are fine, large amounts can cause a blood disorder called methemoglobin. It can also increase your pet’s risk of cancer.

5. Sodium Tripolyphosphate

Another kind of salt, this chemical is more common in detergents than in dog food, but some manufacturers include it as a preservative. It can kill rodents in large doses. In small doses, it can still cause brain problems for your dog.

6. Cellulose

All dog food should have fiber. But, it should be digestible fiber. Cellulose is being added to more dog foods in order to bump up the fiber levels, but your dog won’t actually get any benefit from the food. It’s as if your dog is eating grass which he or she can’t digest.

7. Carrageenan

This chemical is extracted from seaweed and is meant to keep wet dog food at a nice consistency. However, it can degrade into poligeenan, which can upset your dog’s stomach and may eventually lead to cancer.

8. Butylated hydroxyanisole

BHA is a preservative that is widely used in human and pet foods. However, there is evidence that it is a carcinogen that could increase your pet’s risk of cancer. California lists BHA as a carcinogen.

Avoiding these ingredients is a good start to finding a high-quality food for your dog.