We’re living in strange times. Never in living memory have so many people been asked to ‘stay home’ for so long. There’s a lot of focus on the bigger negative effects of being indoors for so long: mental; physical; social; and so on. A less obvious downside of lockdown that recent news reports have brought to our attention is vitamin D deficiency. Health experts are concerned many people are becoming deficient in this crucial vitamin because of a lack of going outdoors in the sun. As Britain doesn’t get great sun at the best of times, they are recommending certain groups of people should be taking vitamin D supplements to top up. Naturally, as a nation of animal lovers, questions have arisen as to whether our four-legged friends, who may also be indoors more than usual, should be given vitamin D supplements as well. So today we will be answering the question ‘do dogs need vitamin D supplements?’
What Even Is Vitamin D?
It’s probably important to explain what vitamin D is. Why it’s actually important first, so prepare yourself for a little biology lesson! Vitamin D is a molecule that has a number of effects on mammalian bodies, both ours and our pets. We will refer to human vitamin D throughout this section, but the biology is similar in almost all mammals, including dogs.
Vitamin D’s primary function is to maintain what we call ‘calcium homeostasis’, or normal calcium levels. Calcium is an important component of bones and muscles. It is also used for muscle contraction, signalling between cells and coagulation of blood if we are injured. Too much or too little calcium can be disastrous, so vitamin D is crucial to maintain calcium homeostasis.
The way vitamin D does this is actually quite complex, and involves a number of different organs. The inactive form of vitamin D gets into our body either via dietary intake or via the skin (more on this later). While inactive it has no effect. In our necks, we have an organ called the parathyroid glands that detects blood calcium levels. If it detects that calcium is too low, it releases a hormone called parathyroid hormone. This hormone acts on the liver and kidneys. It tells them to convert inactive vitamin D into active vitamin D3 (calcitriol). Active vitamin D3 causes our intestines to absorb more calcium and reduces kidney excretion of calcium. In short, when calcium is low, vitamin D acts to increase it back to safe levels again.
Vitamin D also has a number of secondary roles including phosphorus homeostasis (another key component of bones), remodelling of bones after damage or exercise, dental health, immune system regulation, vision and muscle growth. It is safe to say that vitamin D is a very important molecule for healthy people and dogs!
Dogs and Vitamin D
We’ve mentioned above that we can get vitamin D from our skin. The way this works is ultraviolet (UV) light from the sun. It is absorbed by a precursor to vitamin D found in the skin, converting the precursor to inactive vitamin D. It can then go to the liver and kidneys to be converted to active vitamin D3. This is why there has been a lot of focus lately on the effects of low sunlight during the lockdown. If not enough sunlight hits our skin, we may not be producing enough vitamin D to meet our bodies’ requirements. But is this true for dogs?
While dogs do indeed convert some sunlight to vitamin D, unlike people and many other mammals, they are not very efficient at this. Most of a dog’s (and cat’s) vitamin D should come from their diet. As dogs are primarily carnivores (though can consume vegetable matter), they have evolved to absorb most of their dietary vitamin D from meat (whereas cats must consume all of their vitamin D from meat). Good sources of the vitamin for dogs include liver, fish, eggs, beef and dairy products. Having sufficient amounts of these in your dog’s diet will prevent vitamin D deficiency and low calcium causing weakened bones, poor muscle activity, heart disease and other conditions. If there are specific risks of vitamin D or calcium deficiency, vets can prescribe vitamin D supplement tablets for your dog.
Do Our Dogs Need to be Outdoors More Often?
What we can learn from the biology is that if you have a healthy dog with no signs of vitamin D or calcium deficiency, having less sun will not impact their vitamin D production to a great degree. It is very unlikely a dog with a normal diet would become vitamin D deficient due to a lack of sunlight. Sunlight, of course, has a number of other health benefits, so being outside frequently is highly recommended. Be wary that the same UV light that helps create a lot of vitamin D in humans, and a tiny amount in dogs, can be dangerous. UV light damages dog skin in the same way as it does human skin. Particularly lighter skin and skin with less hair. Dogs can be sunburnt and long-term UV light exposure can increase the risk of skin cancers. These can be prevented in the same way we protect our skin. Reducing long-term sunlight exposure, staying out of direct sunlight, and using suntan lotion (human suntan lotion can be used. Though dog-friendly products are available) on pink or white skin (skin, not fur, so part the hair to check).
It is not impossible, of course, that dogs can be vitamin D deficient. Some commercial pet foods contain low amounts of vitamin D in them. For some dogs, this can result in a deficiency. However, there is no easy way to tell just from the product what is sufficient for your dog. Every dog is different, requiring different amounts of vitamin D and absorbing more from their food. If you are suspecting your dog has low vitamin D, it is best to visit your vet first. They can perform blood tests that will indicate if your dog is deficient. From here, they can recommend a changed diet or vitamin D supplements. It is very important that you do not introduce more vitamin D into your dog’s diet. Get proper veterinary advice, as we will discuss next.
Too Much of a Good Thing?
Clearly vitamin D is important for animal health, but just like carbohydrates or fat, too much vitamin D (vitamin D toxicity) can be quite harmful. Excess vitamin D is usually removed from the body. However if there is a sudden huge intake of vitamin D, or a high intake over a long time, our dog’s bodies may not be able to cope. Vitamin D will have the same effect regardless of its amount. So vitamin D toxicity results in more calcium being pulled from bones, more being absorbed from the diet and less being excreted by the kidneys. This results in too high calcium levels, or hypercalcaemia.
Hypercalcaemia can lead to muscle damage, twitching and seizures, kidney and intestine damage, vomiting and constipation, and excess urination. In severe cases, it can be fatal. On top of this, the weak calcium-deficient bones are at greater risk of damage or fracture. Although dogs are more resistant to vitamin D toxicity than herbivorous animals, they are still at risk. This is why we advise you to never give human vitamin D supplements to your dog (as they often contain far too much vitamin D), and only increase their dietary vitamin D after veterinary advice.
Closing Thoughts
Now that you are an expert on all things sunlight, calcium and vitamin D. Hopefully you will see that there is no reason to supplement your dog with vitamin D if they are not getting outside as much during the lockdown. Your healthy, happy dog probably has sufficient vitamin D in their diet. If you aren’t convinced, discuss any concerns you have with your vet, and they can safely guide you on how best to increase your dog’s vitamin D intake if necessary. Don’t forget that humans are different, and we definitely do need a little sun now and then to keep our vitamin D topped up. So while the sun is out, catch some rays. But remember that if you have a furry little friend with you, you’ll both need some suntan lotion behind the ears!
Discussion
I have a question for David Harris. I read about vitamin D3K2 for your dog. How much would you give a GSD of 100 lbs? She is on a raw diet. No dog food because she was not doing well with it. She is going to be 11 y.o. in September. She as well as her litter mate brother have lupus. She developed a squamous cell tumor on her toe pad. I want to support her immune system and help her osteoarthritis in her left knee. Any other suggestions you may have would be greatly appreciated. Thanks.
For healthy adults, the TOTAL amount of vitamin D is recommended as 55.2IU per 100g (dry matter, so excluding all moisture) of food eaten. However, on a raw diet, assuming it’s an animal based diet, there shouldn’t be a specific need for supplementation, and you should be very careful as it is possible to poison a dog with too much.
I’d strongly recommend seeking advice from. board certified nutritionist rather than trying to make it up yourself!
Well, I don’t agree with that. You just need to give your dog the correct dose for it’s weight in pounds. 35 X body weight in pounds in ius. My chihuahua weighs 3 pounds, that is 100 ius a day. Many dogs don’t go out in the sun. They are walked early morning and evening so no vitamin D from the sun . They need a supplement
No, they do not. If they’re eating a properly balanced diet, that’s all they need – they don’t make it in their skin like we do! If they aren’t on a balanced diet, then vitamin D deficiency is the least of their problems, and they need a proper diet, not supplemental vit D only.
I would like to know how you used the baking soda did u put it in the dogs mouth? Maybe
like a paste? Forgive me if u said already and
I missed it, loved your story so glad your dog is
Doing better, thanks in advance
I am a US citizen living in Mexico. I have a dog with squamous cell carcinoma of the mouth. I know this sounds crazy but the cancer is about 1/3 of what it was and I am using baking soda as chemo and radiation are not options. The baking soda has literally pulled the cancer out of her tongue, leaving a tumor that is shrinking and almost gone.
She is currently on a soft, homemade, low carb diet as well. Only Vit D is in her chicken and broccoli. There are no labs in Mexico that test for dog Vit D. I’m not sure what to do, here. Suggestions?
Michelle.
Your story is of great interest to me. I’m an animal naturopath studying natural modalities to help dogs with cancer. There are several references to people having used baking soda for cancer. Since you have carefully documented this, I would like to connect with you to learn more.
Thomas. I have two GSD’s from the same litter. They both have lupus. They each have a degenerative left knee. And 3 months ago my girl Zoey developed a squamous cell tumor on her right medial toe pad. The vet said to use Manuka honey with antibiotics because of the bacteria that grew. But since starting the honey it’s spreading. I want to treat her lupus. I stopped the honey and we’re now doing baking soda soaks. I know I can get this to reverse. I also wanted to give her vitamin D3 K2. Any suggestions? And do you know how much D3 K2 for a 100 lb dog?
Can you leave an email address?
David Harris … Thank you for your reply! There are no veterinary nutritionists here. I am a US citizen living in Mexico. I tried that. To be honest, when she was first diagnosed about 4 months ago I was told she only had a few short weeks to live, maybe up to 2 months. I didn’t care about nutrition at that point. I was just giving her a soft diet. I did not think in a million years the baking soda would have an effect, I felt as though I was doing it to just try something vs. nothing. I was floored when it was actually working. I was not using the diet for nutrition, I just wanted to give her what she wanted as well as a soft diet so it would be easier for her to eat.
This is shocking to me, I am a nurse, I surely did not expect ANY results AT ALL, the cancer is no longer IN her tongue, and the tumor under her tongue is about 1/3 the size that it was. So the goal here was never a diet for nutrition, it was a soft diet – giving her what she wanted.
I did try to find a vet that specialized in nutrition and they do not exist for at least 300 miles from where I am and what I find online is very conflicting.
Maybe I am not getting to the deeper tissues, but you could fool me, it was coming out the other side of her tongue and that is gone. Completely. I have monthly video progression videos and I will take what I can get. ;o) I used to hear people talk about pH and cancer and I thought they were nuts. There is no denying what I have seen with my dog. It is something I NEVER expected. Not in 1,000,000 years. My vet and her (vet) husband have never seen anything like this in 21 years of practice. I’ll take what I can get. ;o) Her labs are great, she’s gaining weight, she’s happy…I’ll take it all! ;o))))
Since she is doing so well I need to get her back on a regular diet but I don’t think I’m going to do kibble. I will look at canned. But in the meantime, can a dog take Vit D supplements?
Thank you so much!!
Can you share the exact diet? thank you and the amount of baking soda, and how big is your dog?
That’s fantastic news!
So, regarding vitamin D, the standard guidelines was always approximately 500 IU per kg of dry matter in the food for maintenance, which equates to about 12.5ug per kg of DRY matter food fed. However, overdose can result in serious toxicity, and if you don’t know how much vitamin D is in the food you’re feeding, you have no way of knowing how much would be safe!
Oh my goodness, thank you **SO** much! This is exactly the information I was looking for. I can’t thank you enough!!!
Definitely get in touch with a veterinary nutritionist – it’s very, very hard to get a balanced home-cooked diet, and with adding the bicarbonate you’re messing around with the acid-base balance as well as chemically debulking the mass (although you probably aren’t getting to the deeper tissues).
This looks like a good site. Will bookmark it for the future. Do dogs benefit from sun for Vitamin D? In Central Mexico we always have sun but Bela has a coat of white fur, almost like hair. She loves the sun but also the shade. I am 91, blond, so we both need the sun.
Not really – dogs generally don’t synthesise much vitamin D or any other substance from sunlight, unlike humans. They are still at risk of skin cancer (especially white or hairless dogs), so do be careful!