For your dog, vitamin E is essential for health. It's also one nutrient that can be confusing to a lot of dog parents committed to giving your dogs the right nutrition for their best life.

Let's dive into what makes vitamin E so important in a complete and balanced diet - and what you need to know about feeding it for the greatest benefit to your dogs.

What is vitamin E

Vitamin E (scientific name is tocopherol) refers to 8 different vitamers (forms of a vitamin that we will discuss below). Like vitamins A and D, vitamin E is a fat soluble vitamin (absorbed along with fats in the diet and stored in the body's fatty tissue and in the liver) facilitating multiple health benefits for our dogs.

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What vitamin E does for our dogs

For dogs, vitamin E is a critical antioxidant and essential vitamin - acting as a protector of polyunsaturated fat (Omega 3, for example) and our dogs' (and our) cells, keeping them healthy.

What does that actually mean?

Polyunsaturated fat is a type of fat found in the body and the diet. In the diet it comes from vegetable oils, fish, fish oils, nuts, and seeds. It can also be found in land animals to a lesser degree. Poultry fat and skin can contribute appreciable amounts of these fatty acids to the diet.

These fatty acids are prone to oxidation.

Oxidative stress can damage cells, proteins, and DNA, which can contribute to aging and play a role in development of a range of health conditions, including diabetes, cancer, and more. Antioxidants work to counteract these free radicals.

Dogs, like humans, are made up of cells. These cells have a fatty membrane that allow for things to go in and out of the cell in a controlled manner. The membranes are made up of fatty acids (a topic we will go into in great detail later).

The cellular membrane is made up of polyunsaturated fat. These fats are fragile and when they oxidize they shatter like glass- affecting all other things around it. It has a domino-like effect. When one fatty acid is oxidized, it becomes a free radical and destroys the other fatty acids. 

It is imperative, then, that this chain reaction be stopped so these broken fatty acids do not move on to destroy the membrane, organelles, and even the DNA.

Enter vitamin E! Vitamin E’s chief function is to protect fatty acids in the cell (and therefore everything else in the cell). 

Once vitamin E is used to stop the chain reaction of oxidation, it must be rejuvenated in your dog's body. The entire antioxidant defense system actually goes beyond just vitamin E to include other key players such as vitamin C, selenium, and manganese that support vitamin E and help its regeneration.

It's important to note that vitamin E prevents the chain reaction from happening - and at the same time, we need to be mindful of the amount of polyunsaturated fat in our dogs' diets. As mentioned before, vitamin E needs to be repaired after acting as protector, so while some types of fat increase vitamin E needs, matching the vitamin E levels is only part of the picture and it's best to not overdo it.

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What is the impact of vitamin E deficiencies

Vitamin E is actually the name for 8 different vitamers. There are 4 tocopherols and 4 tocotrienols. The one we meet the daily requirement with is called d-alpha tocopherol. 

Given that vitamin E protects by extension all things in the cell, it's worth considering that chronic illness may possibly be related to low antioxidant diets commonly fed to dogs.

Key areas impacted...

• Tocopherol comes from the Greek word and originally meant “to carry, to bear, birth.” Vitamin E deficiency in dogs affects the reproductive system.

• Anywhere that is rich in these polyunsaturated fatty acids will be affected the most. Therefore, neurological disturbances can also be seen. The brain is extremely rich in polyunsaturated fat (as DHA) and to do its job results in the byproducts of oxidants. It is critical that optimal vitamin E be provided in the diet to protect the body from oxidative harm.

In humans, low vitamin E has also been linked to cancer, heart disease, joint degeneration, poor wound healing, skin disturbances (like dry, itchy skin, eczema, etc.) and gut disturbances. 

• In dogs, we can also see gut and skin disturbances, poor wound healing, anorexia, eye disease, and in severe cases - death.

A diet that is low in vitamin E and high in polyunsaturated fat is the biggest risk factor for vitamin E deficiencies.

A traditional raw diet that only has meat, bones, and organs can still have varying ranges of polyunsaturated fat. Most raw diets are low in vitamin E relative to the amount the dog needs - even with a low polyunsaturated fatty acid intake.

Which dogs need more vitamin E

Canine athletes require more vitamin E. Things that require high energy- building things, tearing them down, building more things in the process of high activity - produce oxidants.

Some conditions, such as chronic kidney disease, will also benefit from extra vitamin E. Just be careful to not use plant oils high in polyunsaturated fat (fish and fish oils are still beneficial).

What happens with excessive vitamin E

Unlike vitamin A and vitamin D, vitamin E doesn’t really have a toxic excess amount. Remember that vitamin E refers to all the tocopherols and tocotrienols. High amounts of d-alpha tocopherol, especially when fed without the other tocopherols, can begin to have the opposite effect of its usual protective role.

Effects & interactions of mega dosing

Mega dosing (tending toward a vitamin E overdose) can cause vitamin E to have a more oxidative effect, creating oxidative damage. That's why it's important to not supplement carelessly even though the safe upper limit is not specifically defined.

Also good to note that high doses of vitamin E may hurt vitamin K status.

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Where to find vitamin E in food:

Plant sources - spinach, various greens, pumpkin, avocado...

Vitamin E can be found in plants because plants use a process called photosynthesis. This process uses oxygen, water, and the sun to make glucose. This process requires that the plants have adequate antioxidants, so it is not surprising we see vitamin E scattered among plant-based foods.

Grass-fed and finished (physically mature) beef will also have higher vitamin E than factory-farmed beef because of the cows' diet.

Food choice watch-outs

If we were to look at foods just based on their vitamin E content, it would appear that wheat germ oil would be the best source. However, wheat germ oil is also extremely rich in polyunsaturated fat. Therefore, the vitamin E in the oil should not be counted toward daily requirements for the body’s metabolic functions. Similarly, brain should also not be used for vitamin E requirements because it is so rich in polyunsaturated fat.

Considerations if vitamin E supplementation is needed

If you're choosing vitamin E supplements, it's good to know they tend to come in a few forms:

• As d-alpha tocopherol (with nothing else)
• As dl-alpha tocopherol
• As d-alpha tocopherol with mixed tocopherols
• As d-alpha tocopherol with mixed tocopherols and tocotrienols

Dl-alpha tocopherol is synthetic and is less bioactive than d-alpha tocopherol. For those reasons, I do not recommend you use dl-alpha tocopherol.

I recommend using d-alpha tocopherol with mixed tocopherols (and tocotrienols when possible). The tocopherols outside of d-alpha may have unique benefits and so I opt to include them when possible.

It can be somewhat difficult getting smaller dogs a small enough dose of d-alpha with mixed tocopherols. In that case, try to be sure to include a wide array of plant foods in your dog's diet.

Tocotrienols can also be found in some supplements, but data is lacking on how absorbable they are. When possible, I prefer to use a supplement with d-alpha tocopherol with mixed tocopherols and tocotrienols.

How to add vitamin E to commercial pet foods with toppers

To enhance kibble:

Provide fresh plant foods. A low dose vitamin E supplement can also be added. Supplement vitamin E if adding fish or fish oil.

If you're feeding raw:

Most raw foods that are properly formulated should have enough vitamin E. If you don't see it on the ingredient label, feel free to ask in the Community discussion in the Basic Nutrition Channel or in your nutrition plan on Dogly and share the food that you have.

To enhance canned dog food:

Provide fresh plant foods to enrich vitamin E and other antioxidants.

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How much vitamin E does your dog need

Try this

You're welcome to use the calculator I built here to determine vitamin E requirements. This will not account for extra polyunsaturated fat that may be in your dog's diet.

If you are feeding oily fish, fish oil, plant oils (like sunflower, hemp etc), consider supplementing. The more polyunsaturated fat you feed in these foods, the more vitamin E required!

Steps to evaluate vitamin E in your dog's diet

1. Identify vitamin E in your dog's current diet.
2. Where is the vitamin E in your dog's diet? How often is vitamin E fed?
3. Is this a good source? 
4. Is it from food? Is the food high in polyunsaturated fat? Is it a supplement? If so, what form? Any tocopherols or tocotrienols?
5. How much is in your dog's diet?
6. Does your dog have an increased need for vitamin E?

All these questions and the answers are applicable for homemade diets and some commercial whole food diets that provide ingredient amounts. 

When figuring ingredient amounts, be sure to consider your dog’s age, weight, and ideal weight.

Next up in the Basic Nutrition Channel on Dogly

Now that you have a good understanding of vitamin E, continue to the next essential vitamin step-by-step guide on vitamin K.

Or hop over to the Basic Nutrition Channel if you'd like to ask a question in the Community discussion and start any of the other step-by-step guides in Needed Nutrients. If you ever need more personalized nutrition guidance, please reach out!

Sources:

NRC Nutrient Requirements of Dogs and Cats (2006)

Canine and Feline Nutrition

Small Animal Clinical Nutrition

Chris Masterjohn, PhD Vitamins and Minerals

DSM