Fish oil and vitamin D are not connected in the same way in dogs and cats
If you are looking for a combined supplement of fish oil and vitamin D, it is worth knowing from the outset that the two substances do not necessarily belong together when it comes to dogs and cats. In humans, omega 3 and vitamin D are often combined in a single capsule, because we both struggle to get enough during winter, when the sun is low. But dogs and cats do not produce vitamin D in their skin from sunlight the way we do. They get virtually all of their vitamin D through their food.
This means that a fish oil for animals is rarely made as a vitamin D supplement. The omega 3 oil from Essential Foods is a pure omega 3 source of EPA and DHA, intended to supply the fatty acids that a food may contain too little of. The need for vitamin D, on the other hand, is most appropriately met through a complete food that is already balanced for precisely the dog or cat.
This text explains what the oil actually contains, how omega 3 and vitamin D differ for animals, and how to use the oil correctly without risking too much of a fat-soluble vitamin.
Why dogs and cats do not get vitamin D from the sun like us
Humans produce vitamin D when UV light from the sun hits the skin. That is why many people take supplements during the winter months, and it is the reason fish oil and vitamin D are often marketed together for us.
Dogs and cats work differently. Their fur and skin do not convert sunlight into vitamin D to any significant degree, and they are therefore dependent on getting the vitamin through their diet all year round. This makes a well-balanced food the most important source of vitamin D, not the sun and not an oil.
Precisely because animals get it from their food, there is also a real reason not to simply add extra vitamin D on your own. Vitamin D is fat-soluble, which means the body stores the surplus instead of getting rid of it. Excessive amounts over time can strain the kidneys and affect the calcium balance. For this reason, a food in which the amount is already balanced is a safer route than loose supplements.
What The Omega 3 Oil contains, and where vitamin D comes in
The Omega 3 Oil is a liquid fish oil that supplies the omega 3 fatty acids EPA and DHA. It is these two fatty acids that are the whole point of the oil: among other things, they support coat, skin, joints and general cell function, and they are typically what a food may lack if the raw ingredients are not sufficiently fish-based.
Fish oil from oily fish naturally contains a certain amount of vitamin D, because vitamin D is fat-soluble and follows along with the fish's fat. But the amount varies from batch to batch and from fish species to fish species, and an omega 3 oil is precisely not standardised like a vitamin D preparation. You should therefore not regard the oil as your dog's or cat's vitamin D source, but as an omega 3 supplement in which a natural content of fat-soluble vitamins may follow along.
If you want to know the precise content of the particular bottle you buy, you will find the product declaration on the individual product, either THE OMEGA 3 OIL 500ML or THE OMEGA 3 OIL 1L. If you feed several animals or use a lot of oil, the same oil is also available in a THE OMEGA 3 OIL, 1L x 3.
How much vitamin D is in fish oil?
There is no single fixed number, and that is exactly the point. The amount of vitamin D in fish oil depends on which fish the oil comes from, which part of the fish it is extracted from, and how the oil is processed. Oil from oily fish such as salmon, mackerel and herring contains more than oil from leaner species, and cod liver oil, which comes from the liver, contains markedly more vitamin D than ordinary body fish oil.
For an omega 3 oil for animals, the vitamin D content is a by-product of the fish fat, not a dosed content that you can calculate backwards from. For this reason, you should never use the fish oil as a starting point for meeting an animal's vitamin D need, and certainly not stack several vitamin D sources on top of each other without knowing what they add up to together. If you are unsure whether your dog or cat is getting enough, or too much, that is a question for the vet, not something to be decided on the front of the bottle.
How to dose the oil without overdosing on fat-soluble vitamins
Because both the omega 3 fatty acids and the fat-soluble vitamins are stored in the body, good use of the oil is more about method and amount than about giving as much as possible.
- Follow the dosage on the bottle according to the animal's weight rather than estimating by eye.
- Start with a smaller amount and build up over a few days, so the stomach gets used to the fat.
- Pour the oil directly over the food just before serving, so it does not have time to go rancid.
- Store the bottle in a cool, dark place and close it well, as omega 3 is sensitive to light and oxygen.
If you are already feeding a complete food, the animal's vitamin D is already covered through its food. The oil should then be seen as a supplement of omega 3, not as something that needs to correct a vitamin D requirement. If you want to understand the background of what oil of this type does, you can read more in the articles what is fish oil good for and what is omega 3.
Dogs and cats have different needs
The oil can be used for both dogs and cats, but the animals' starting point is not the same. Cats are strict carnivores and have a narrower margin for what they can tolerate of fat-soluble vitamins, while dogs usually have a broader one. For both, the amount must match the weight, and a small cat should have far less than a large dog.
This is also where the difference between the species becomes practically relevant: what is an appropriate daily amount of oil for a Labrador may be too much for a small cat. For this reason, weight-based dosing is more important than one fixed spoonful for everyone. If you are curious about which type of fish oil is best suited, the article which fish oil is best for dogs provides an overview.
