Bad Dog Food Ingredients to Avoid

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Over the past few days, I have been writing about different problematic ingredients that we recommend our readers here to watch out for so they can avoid giving them to their dogs. In this article, I have put all the ingredients providing details of why we are against them;

Who decides which ingredients to include in dog food?

But first, let’s understand dog food and how dog food manufacturers decide which ingredients to include.

AAFCO defines “complete and balanced” dog food as follows:

“Complete and balanced nutrition for all life stages is achieved through significant levels of the nutrients required by the AAFCO Dog Food Nutrient Profiles or through other means that have been proven to provide equivalent nutrient values.”

In order to be considered “complete and balanced,” pet food must provide, in the proper proportions:

  • Water
  • Protein
  • Fat
  • Carbohydrates
  • Minerals
  • Vitamins

And, it must be formulated to meet one of these two goals:

1) To provide all the nutrients required for “growth and reproduction” (puppies and pregnant or nursing dogs); or

2) To provide all the nutrients required for “all life stages” (adult dogs).

Now that we know what complete and balanced nutrition looks like, let’s move on to the ingredients.

AAFCO uses the FDA’s list of safe ingredients and the National Research Council’s recommendation on food ingredients to recommend. AAFCO has a specific minimum and maximum requirements for 22 nutrients that all pet foods must meet. WSAVA also has general guidelines but are not as detailed as AAFCO.

However, there are no regulations on the quality of ingredients used in pet food. So, manufacturers can choose to use the cheapest and most readily available ingredients, even if they’re not necessarily the best for your dog.

Here are some of the most common red flag ingredients found in dog food:

Bad Ingredients in Dog Food

1. Animal By-products

By-products are the parts of the animal that are not fit for human consumption and are referred to as inedible. This can include the following;

  • Hair/fur/coat
  • Bones
  • Liver
  • Teeth
  • Lungs
  • Hooves
  • Heads
  • Horns
  • Blood
  • Brains
  • Spleen
  • Kidneys
  • Stomachs
  • Intestines
  • Skin/leather

While by-products do contain some nutrients, they are not as high quality as meat.

When pet food manufacturers want to avoid the more expensive human-grade protein, they opt for by-product meats that are low in quality and have significantly lower biological value.

AAFCO defines meat by-products as “the non-rendered, clean parts, other than meat, derived from slaughtered mammals.” This includes organs like the liver, horns, skin, kidney, and brain.

While some by-products can be nutritious, it’s important to know that they are not regulated as stringently as human-grade meat.

So, if you see “by-products” listed on the ingredient label, it’s best to avoid that food.

While some organizations such as the Pet Nutrition Alliance, which was quoted by Purina as having said that “by-products are used in pet foods because they are excellent sources of protein and other nutrients.”

As you read reports and recommendations about pet food ingredients, be wary of those made by pet food manufacturers such as Purina as they have a vested interest in marketing their pet food products made from animal by-products.

There are two forms of animal by-products as used by pet food manufacturers;

  1. Named animal by-product meals: These are by-products from a specific animal that is named on the product label such as chicken meal or lamb meal.
  2. Generic (un-named) by-product meals: These are by-products from single or multiple animals that are not named on the product label.

If you do opt for dog food with by-products, avoid the generic by-product meals that do not name the source of the by-products.

Go for products that have labeled their products with words that identify the meat source such as;

  • Chicken by-product meal
  • Turkey by-product meal
  • Poultry by-product meal
  • Beef by-product meal

Avoid dog food with ingredients that do not identify the source such as;

  • Meat and bone meal
  • Meat by-product meal
  • Animal by-product meal

Though it happened in a foreign country (not here in the US), there have been cases of zoo animals being hunted and getting utilized as protein sources for some pet food. This is one of the main reasons I shy away from unnamed protein sources.

Dog Food Advisor went further to indicate that unnamed animal by-products sources could be;

  • Animals that died from road accidents or ‘road kill’
  • Animals that died in zoos
  • Dead poultry
  • Dying livestock with diseases
  • Dogs and cats that have been euthanized.

2. Fillers

Fillers are ingredients that are used to bulk up the food and make it cheaper to produce. They are usually carbohydrates or grains that provide little to no nutritional value for your dog.

AAFCO has not defined fillers, but they are often thought of as unneeded ingredients that serve no purpose other than to increase the volume or weight of the food.

Fillers are used in pet food to cut costs and they provide little to no nutritional value for your dog.

Some common fillers include:

These ingredients can cause digestive problems for your dog and can also lead to allergies.

Some fillers could also contain gluten. Wheat, corn, and soy are all common sources of gluten.

Gluten can cause digestive issues for your dog and can also lead to allergies.

When a dog food brand has fillers with no nutritional value and has gluten, there is no reason to get it at all.

Some have made the case that some fillers do have nutritional value such as  corn gluten meal as they are high in protein.

While this may be the case, there are plenty of other high-quality protein sources that don’t come with the same health risks as corn gluten meal.

I have written an article explaining why you should avoid rice brewers here.

3. Vegetable Oil:

Vegetable oil is a broad term that can be used to describe any oil that is derived from a plant.

The most common type of vegetable oil used in dog food is soybean oil, canola oil, sunflower oil, alfalfa oil, and corn oil, among others.

All vegetable oils have high levels of Omega 6 which is an essential fatty acid necessary for inflammation in dogs. Inflammation is a normal bodily response, but too much of it can lead to health problems.

A diet high in Omega 6 can cause:

  • Allergies
  • Skin problems
  • Digestive issues
  • Immune system problems
  • Cancer

When it comes to essential fatty acids, the ideal balance between Omega 3 and Omega 6 is important.

Most commercial dog food brands already have more than enough essential fatty acids and the addition of Omega 6 from vegetable oil may lead to further inflammation, allergies, and other health problems. Too much Omega 6 can exacerbate arthritis and hip and joint problems.

We have more descriptions of the problems with soybean oil, corn oil, sunflower oil, and canola oil, among others.

Alternative: Go for dog food brands that use named fish oils (such as salmon), olive oil, or flaxseed oil.

4. Soy

Protein is another problematic ingredient often used in plant-based protein sources. While it is among the few plant-based protein sources that contain all the essential amino acids, it is not easily digestible by dogs and often results in dogs having gas and bloat.

Soy is also a common allergen for dogs. According to the FDA, soy allergies in dogs are on the rise.

While it is possible to find dog food brands that use soy protein isolate (a more concentrated form of soy that is less allergenic), it is best to avoid soy altogether.

There are plenty of other protein sources that are more easily digestible and don’t come with the same health risks. I have listed 6 problems with soy (soybean oil, soybean meal) as dog food ingredient.

5. Artificial Preservatives

Artificial preservatives are synthetic ingredients that are used to extend the shelf life of food.

They are often used in processed foods, including pet food.

The most common artificial preservatives used in dog food are BHA, BHT, and ethoxyquin.

These preservatives have been linked to health problems such as cancer, liver damage, and reproductive issues.

While natural preservatives such as vitamin E (tocopherols) and vitamin C (ascorbates) are available, they are not as effective as artificial preservatives.

As a result, many dog food brands still use artificial preservatives even though they are aware of the health risks.

If you are concerned about the health of your dog, it is best to avoid dog food brands that use artificial preservatives.

6. Gluten:

Gluten is a protein found in wheat, rye, and barley. It is used as a binding agent and can often be found in processed foods.

While gluten is not necessarily harmful to dogs, it can cause digestive issues and allergies.

Gluten is also a common allergen for dogs and FDA has noted the rise in gluten allergies in dogs.

If your dog has a sensitive stomach or suffers from allergies, it is best to avoid dog food brands that use gluten.

Alternatives: Sweet potatoes, or gluten-free grains such as oats or buckwheat.

7. Artificial Colors and Flavors

Artificial colors and flavors are synthetic ingredients that are used to enhance the appearance and taste of pet food. The most common artificial colors used in dog food are blue 2, green 3, red 40, and yellow 5 and 6.

These artificial colors have been linked to hyperactivity and several biochemical issues that have been known to cause cancer, allergies, and behavioral issues.

As dogs can only see blue and yellow, it is possible that some artificial colors may not even get noticed by your dog and may not enhance his chances of eating the kibble. Whether you feed in the dark (can dogs see in the dark?) or during the day, colors may not impact their appeal.

While natural colors and flavors are available, they are often more expensive and not as effective as artificial colors and flavors.

As a result, many dog food brands still use artificial colors and flavors even though they are aware of the health risks.

If you are concerned about the health of your dog, it is best to avoid dog food brands that use artificial colors and flavors.

Alternatives? No need for alternatives as your dog doesn’t need artificial flavors or colors.

8. Corn:

Corn is one of the most common ingredients in dog food. They are several types of corn and being a heavily subsidized grain here in the US, it is very cheap and dog food manufacturers like to use it as a protein, filler, and source of energy.

While there’s nothing inherently wrong with corn, it’s not an ideal ingredient for dogs.

Dogs are carnivores and their digestive systems are designed to digest meat, not plant material. So, while corn is not toxic to dogs, it’s not an ideal protein source as it is very hard for dogs to digest and obtain the nutrients from them.

Corn is also lacking some essential amino acids and this is common with plant-based protein sources. It’s lacking threonine and leucine amino acids.

Threonine is an essential amino acid that helps maintain heart health, liver function, and central nervous system function.

Leucine is another essential amino acid that’s important for muscle growth and repair. Both of these amino acids are found in meat but are lacking in corn.

It’s also worth noting that corn is one of the most common food allergies in dogs.

If your dog is showing signs of a food allergy, such as itching, excessive licking, hair loss, or diarrhea, corn could be the culprit. I have written a detailed article on the 6 key problems with corn and corn meal

Alternatives: Sweet potato for carbs or named protein sources such as chicken. You can also check out our list and reviews of of best dog food without corn

9. Garlic:

ASPCA lists garlic as toxic food for dogs and Pet Poison Hotline now lists garlic is poisonous to dogs and cats. It is 5 times more toxic than onions.

While a small amount of garlic is not likely to do any harm, eating large quantities can cause anemia in dogs. Some studies indicate that Japanese breeds such as Shiba Inu are more susceptible to garlic and onion toxicity.

Anemia is a condition where there are not enough oxygen-carrying red blood cells in the body. This can lead to lethargy, weakness, and even death.

If you’re feeding your dog commercially prepared food, it’s unlikely that there will be large quantities of garlic in the food.

But, if you’re making your own dog food or giving them table scraps, it’s important to avoid giving them garlic. Read all the 4 reasons why we do not recommend garlic as dog food ingredient here.

Please check back soon as I will be adding this list.


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