6 Problems with Soybean Oil and Soybean Meal in Dog Food

Soybean extracts and specifically soybean oil and soybean meal are among the problematic ingredients in dog food that we don’t like. In this article, I have explained in detail why soybean oil and soybean meal are not suitable for dogs.

What are soybean oil, and soybean meal?

Soybean is one of the many plant-based protein sources used in pet foods. It is a legume, similar in composition to peas and beans. Whole soybeans are about 40% protein and 20% fat.

To produce a soybean meal, the whole soybean is first crushed and the oil is extracted using a solvent. The remaining “cake” after the oil has been extracted is called soybean meal and it is about 50% protein.

Soybean oil is the most common form of soy used in pet foods and it is 100% fat.

Soybeans are a source of essential fatty acids, vitamins, and minerals, and contain all the amino acids needed to form a protein.

In dog food, fat provides twice as much energy as carbohydrates or protein as the oxidation process of fat produces more ATP, the energy used by cells.

Soybean oil is a common ingredient in commercial dog food. It is a source of essential fatty acids and energy for dogs. However, soybean oil is not a necessary ingredient in dog food and there are some potential problems associated with its use.

Structure of essential fatty acids:

Fatty acid functions are determined by their structure and composition. Fatty acids are categorized according to the length of their chain and the number of double bonds they contain.

Saturated fatty acids have no double bonds and are solid at room temperature. Unsaturated fatty acids have one or more double bonds and are liquid at room temperature.

Polyunsaturated fatty acids (PUFAs) have more than one double bond. The most important PUFAs for dogs are linoleic acid (an omega-6 fatty acid) and alpha-linolenic acid (an omega-3 fatty acid).

Essential fatty acids are PUFAs that cannot be synthesized by the body and must be obtained from the diet. Linoleic acid is an essential fatty acid for dogs, while alpha-linolenic acid is not.

Soybean oil is a significant source of PUFAs in commercial dog food. It is a plant-based oil that contains a high proportion of linoleic acid (an omega-6 fatty acid).


A diet that contains too much linoleic acid and not enough alpha-linolenic acid can lead to inflammation. Inflammation is a normal immune response but, when chronic, it can lead to a number of health problems.

Dogs that consume a diet high in soybean oil may have an increased risk of:

  • Allergies
  • Digestive problems
  • Inflammatory bowel disease
  • Autoimmune diseases
  • Cancer

There are two types of essential fatty acids (EFAs) that dogs need: linoleic acid (omega-6) and alpha-linolenic acid (omega-3).

Linoleic acid is found in plant oils such as soybean oil. It is necessary for the development and maintenance of healthy skin and coat.

Alpha-linolenic acid is found in green leafy vegetables and some vegetable oils such as flaxseed oil and canola oil. It is important for the development of the nervous system and for maintaining healthy skin and coat.

Dogs can convert linoleic acid to alpha-linolenic acid, but the conversion is not

FIGURE. Chemical structure of linoleic acid (18:2, omega-6), with important features noted.

Essential Fatty Acids with Numeric Formulas:


Soybean oil and soybean meal nutrient profile:

Saturated Fat:

Soybean contains 12 to 15% of saturated fat. Saturated fat is not considered healthy for dogs as it can increase the risk of obesity and heart disease.

Monosaturated Fat:

Soybean contains 22 to 30% of monosaturated fat. Monosaturated fat is considered a healthy type of fat as it can help to lower cholesterol levels.

Polyunsaturated Fat:

Soybean contains 55 to 58% of polyunsaturated fat. This type of fat is essential for dogs as it provides essential fatty acids, however, too much-polyunsaturated fat can be harmful.

All the essential fatty acids that your dog needs are polyunsaturated fat. Below are the essential fatty acid;

  • Omega-6: LA (linoleic acid) and AA (arachidonic acid): These are pro-inflammatory fatty acids that are necessary for dogs.
  • Omega 3: ALA (alpha-linolenic acid), EPA (eicosapentanoic acid), DHA (docosahexaenoic acid): These are anti-inflammatory fatty acids that are necessary for dogs.

Soybean oil is largely composed of polyunsaturated fatty acids (PUFAs), particularly linoleic acid, an omega-6 fatty acid that accounts for approximately 55% of soybean oil. Linoleic acid is the most essential fatty acid that helps to maintain the health of the skin and coat.

Arachidonic Acid: This is an Omega 6 fatty acid important in cat food but not considered essential for dogs.

However, too much AA can lead to inflammation.

Soybean oil also contains EPA and DHA, two omega-3 fatty acids that are important for dogs as they help them reduce inflammation due to conditions such as arthritis.


Minimum requirements for essential fatty acids in grams per 1000 kcal:

AAFCO recommends 21.3 grams per 1000kcal in growing dogs and 13.8 grams per 1000 kcal.

This is further broken down as follows;

  1. 3.3 grams of linoleic acid for growing and 2.8 grams/1000 kcal for adult maintenance
  2. 0.2 grams per 1000 kcal for alpha-linolenic acid
  3. 01. grams per 1000 kcal for Eicosapentaenoic acid and docosahexaenoic acid

The fat in soybean is mostly polyunsaturated with a small amount of saturated and monounsaturated fatty acids. Other oil high in polyunsaturated fat are corn oil and safflower oil.

What’s wrong with soybean oil in dog food? 3 Main Problems:


The main problem with soy in dog food is that it is a common allergen. In fact, soy is one of the most common food allergies in dogs.

While some dogs can eat soy without any problems, others may develop allergic reactions ranging from mild to severe.

Soybean Allergy in Dogs:

The main problem with soy in dog food is that it is a common allergen. In fact, soy is one of the most common food allergies in dogs. While some dogs can eat soy without any problems, others may develop allergic reactions ranging from mild to severe. Symptoms of a soy allergy

Soy is one of the most common food allergies in dogs. While some dogs can eat soy without any problems, others may develop allergic reactions ranging from mild to severe.

Common symptoms of a soy allergy in dogs include:

  • Itchy skin
  • Hives
  • Rash
  • Diarrhea
  • Vomiting

Has goitrogens which impact thyroid gland’s functioning:

Soybean contains goitrogens, which are substances that can interfere with the production of thyroid hormones.

Goitrogens are found in soybeans and other legumes, such as peanuts and lentils. They can also be found in certain cruciferous vegetables, such as broccoli, Brussels sprouts, cabbage, and kale.

While most dogs will not be affected by the goitrogens in soy, some may develop hypothyroidism if they eat too much soy.

Read this study here.

Soybean oil is an endocrine distractor:

In a 2010 study titled by Reifen et al, published in Journal of Pediatric Endocrinology & Metabolism and titled ‘Soy as an Endocrine Disruptor: Cause for Caution?’ authors concluded that soybeans ‘alter the function of the endocrine system and consequently cause adverse health effects.’ It went further to note that long-term exposure to soybeans is ‘associated with formation of malignancies and several anomalies of the reproductive systems.’

Endocrine-disrupting compounds (EDCs) in soybeans include natural estrogens/androgens, synthetic estrogens/androgens, and industrial chemicals. Estrogen stimulates abnormal cell growth and can cause the growth of cancer cells.

In a study titled, ‘Evaluation of effects of dietary soy in Canine Health‘ The study concluded that long-term exposure to soy causes disruption of endocrine function in dogs.

What’s the problem with soybean meal in dog food? 3 main issues:

Poor-quality protein source:

Soybean meal is the by-product of soybean oil production.

Soybean meal is high in protein but it is a poor quality protein because it is lacking in some essential amino acids.

Soybean meal is also high in fiber which can cause digestive problems in some dogs.

In general, soybean meal is not an, not an ideal protein source for dogs.

The vast majority of the soybean meal used in dog food is sourced from China. In fact, over 95% of the soybeans used in animal feed are grown in either Brazil or China.

There have been several reports of contaminated pet food coming from China, so this is a cause for concern.


Another problem with soybean meal is that it is often sour. This is due to the fact that it is a by-product of the soybean oil industry.

Soybean meal that is too sour can cause digestive problems in dogs.

Too much calcium:

Soybean meal is also high in calcium. Too much calcium can lead to health issues such as overgrowing of bones for puppies or kidney issues for adult and senior cats.


  1. U.S. Food and Drug Administration. “Soybean Oil and Reduced Risk of Coronary Heart Disease.” July 31, 2017.
  6. Soybean health
  7. Omega-6 and omega-3 oxylipins are implicated in soybean oil …