Do Dogs Need Vitamin D?

I recently wrote about vitamin C and how it’s not an actual vitamin for dogs since dogs can produce it in their liver, unlike humans. Naturally, it raises the question, can dogs produce other vitamins too? In this article, I go through and explain how vitamin D works and whether dogs need vitamin D supplementation or not.

Related: Do Dogs Need Vitamin C?

How Do Dogs Get Vitamin D?

Dogs do not produce vitamin D on their own and therefore it’s needed from the diet. Kibble and wet food are labeled as ‘complete feed’ which means that the products are designed to contain all the minerals and nutrients a dog needs daily.

So, if you are feeding a recommended amount of food as instructed in the dog food packaging, your dog is most likely doing fine.

Dogs that are raw fed or are fed 50/50, should take a look at their diets and make sure the daily intake of vitamin D is secured. Next, we will discuss how you can add more vitamin D to your dog’s diet.

Sources of Vitamin D

I give my cavaliers 5ml of wild fish oil once every day. If you want to boost your dog’s vitamin D intake, try some of these foods:

• Salmon
• Tuna fish
• Swordfish
• Sardines
• Lactose-free yogurt
• Kefir
• Beef liver
• Egg yolk
• Fish oil supplements

Note that vegetables contain hardly any vitamin D. Dogs thrive eating animal fats and meat.

Do Dogs Get Vitamin D From the Sun?

Dogs do not get vitamin D from the sun like humans. It’s an old misconception that dogs get this vitamin from the sun but it’s not accurate. Dog skin does not synthesize Vitamin D well from the sun’s UVB rays.

Benefits of Vitamin D

Vitamin D is an important building block for dogs too. It is almost like a hormone that ties together many functions and here is a list of the major benefits:

• Helps phosphate and calcium to absorb better
• Maintains the calcium balance in the system
• Supports bone health
• Supports dental health
• Helps maintain gut health
• Promotes functions of the immune system

Due to the reasons listed above, vitamin D is crucially important for a puppy’s growth. Puppies need vitamin D to develop healthy bones and muscles.

Dogs That Need Vitamin D Supplementation

A typical family dog that eats good-quality complete feed such as kibble or wet food doesn’t generally need vitamin D supplements. On the contrary, in 2018 and 2019 FDA reported how some dry dog food contained toxic levels of vitamin D.

But there are situations where supplementation can be beneficial. Here are some of them:

1. Pregnant and nursing dogs
2. Aging dogs
3. Working dogs that endure a lot of physical stress
4. Dogs that compete in different sports
5. Dogs eating raw and 50/50 diets

Signs of Vitamin D Deficiency in Dogs

Most dogs are not likely to suffer from vitamin D deficiency but here are some of the signs:

• Growth disorders in puppies
• The dog’s coat is dull and lackluster
• Hair loss
• Fatigue
• Lethargy
• Heart failure can occur in the most severe cases.

How Much Vitamin D Per Day For Dogs?

Unlike vitamin C, vitamin D is a fat-soluble vitamin meaning that the excess vitamins won’t be flushed with urine. Fat-soluble vitamins are stored in the body and liver. Vitamin D absorbs better when consumed with food. Because fat-soluble vitamins are stored in the body, there is a possibility of overdosing.

Recommendations for daily intake of vitamin D vary from country to country. The National Research Council (US) has determined that the daily intake should be 0,275 μg per kilo.

Calculate: Your dog’s weight in kilos x 0,275 = results.

Example; My dog weighs 7,8kg so my calculation is 7,8 x 0,275 = 2,145μg.

For reference, the National Institutes of Health recommends humans take 15 μg of vitamin D per day. That means small dogs’ daily need for this vitamin is almost seven times less than humans.

When comes to big dogs, let’s say dogs of 30-40 kilos, it’s from 8,25μg to 11μg. This means bigger dogs’ daily recommendation for vitamin D is almost the same as what the daily recommendation is for humans.

What To Do If a Dog Ate Vitamin D Supplements?

As I calculated above, small dogs need seven times less vitamin D daily than humans. But big dogs almost need as much as us. So the level of worry depends on how big your dog is and how much did they eat. 2-3 capsules for a big dog is nothing but a small dog can be affected.

It’s not accurately known what amount of vitamin D will cause toxicity. For humans, it requires 1200μg of vitamin D taken daily over a longer period.

If a human needs 80 times more to get an overdose, a dog won’t be easily in danger either. But if your dog ate a full pill bottle’s worth, a call to your local vet is a good idea.

Conclusion

Dogs need vitamin D for multiple essential body functions. Fatty fish and oil supplements are a great source of vitamin D. A typical family dog doesn’t need extra vitamin D supplementation because normal dog food has all the daily vitamins and nutrients added. There are a few exceptions and some dogs do need vitamin D supplements.