How Steroids Can Cause Vitamin D Deficiency In Dogs

vitamin d deficiency
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Is your dog on steroids? Not the kind that bodybuilders use, but corticosteroids like prednisone. Veterinarians often prescribe these to treat the all-too-common problem of allergies in dogs. 

If your dog is getting steroid drugs for his allergies, there’s some worrying research that you should know about … 

Oral Steroids Lower Vitamin D

A 5-year survey at the Albert Einstein College of Medicine in New York found that people taking oral steroids were twice as likely as the general population to suffer severe Vitamin D deficiency.

The researchers did the study because they noted substantially reduced bone mineral density in people taking steroids. So they wanted to assess how vitamin D levels are affected by oral steroid use. 

Smaller studies involving people often prescribed steroids have found significantly reduced vitamin D levels in these patients. This was the first-ever study of a large, nationally representative sample of people.

They found that 11% of the steroid users had severely low vitamin D levels … compared to only 5% percent for non-steroid users. In other words, taking steroids more than doubled the odds of severe vitamin D deficiency. 

The risk was especially high for steroid users under 18. This group was 14 times more likely to have a severe vitamin D deficiency compared with young non-steroid users. 

The research team concluded that steroid use is independently associated with vitamin D deficiency, suggesting the need for screening and repletion in patients on chronic steroids.

So, what does this mean for your dog who takes steroids? How can vitamin D deficiency affect his overall health?

The Importance Of Vitamin D

Vitamin D deficiency is a global problem affecting about 1 billion people worldwide. 

Research in humans shows that having adequate levels of vitamin D benefits …

  • Bone
  • Blood pressure
  • Kidney disease progression

And helps prevent …

  • Cardiovascular disease 
  • Autoimmune diseases
  • Cancer
  • All-cause mortality

Research in mice shows that vitamin D deficient mice are more likely to suffer from autoimmune disease, hypertension, cardiac problems and oncogene-induced tumors. Other studies show vitamin-D deficient people are more likely to suffer from cardiac risk factors like hypertension, diabetes and high triglyceride levels. 

A 2019 Brazilian study found that low vitamin D in dogs may be linked to higher risk of several problems in dogs, including …

Vitamin D is especially important when it comes to supporting your dog’s immune system. That’s really important when you’re dealing with allergies … because allergies are an improper immune reaction

RELATED: Lower your dog’s cancer risk by increasing the vitamin D in his diet … 

How Does Vitamin D Support Your Dog’s Immune System?

Vitamin D isn’t just important for maintaining strong bones.  It’s a key element of the immune system. In particular, it triggers and arms the body’s T cells, the cells in the body that seek out and destroy any invading bacteria and viruses.

Scientists at the University of Copenhagen discovered that vitamin D is crucial to activating immune defenses.  Without sufficient intake of the vitamin, the T cells (killer cells) of the immune system won’t react to fight off infections in the body.

How T Cells Work

For T cells to detect and kill foreign pathogens such as clumps of bacteria or viruses, the cells must first be triggered into action. They then “transform” from inactive and harmless immune cells into killer cells that are primed to seek out and destroy all traces of invaders.

The researchers found that the T cells rely on vitamin D in order to activate. But if vitamin D is lacking in the blood, the T cells remain dormant, and don’t react to the threat. 

Professor Carsten Geisler said:

“When a T cell is exposed to a foreign pathogen, it extends a signaling device or ‘antenna’ known as a vitamin D receptor, with which it searches for vitamin D.

“This means that the T cell must have vitamin D or activation of the cell will cease. If the T cells cannot find enough vitamin D in the blood, they won’t even begin to mobilize.”

This is important not only in fighting disease but in all immune reactions of the body … including allergies. Active T cells multiply at an explosive rate, so they can create an inflammatory environment with serious consequences for the body. In autoimmune diseases, like arthritis or allergies, T cells mistake fragments of the body’s own cells for foreign invaders. This causes the body to attack itself.

RELATED: Add these foods to your dog’s diet for an immune boost … 

Steroids and Immune Suppression

Allergies stem from an exaggerated immune response to a pathogen. Steroids treat allergies by suppressing the immune system … or more precisely, they inhibit T cell activity. 

Using steroids to control allergies is merely suppressing symptoms. And it causes dangerous side effects including …

Steroids aren’t the only drugs that suppress the immune system.  Popular allergy drugs like Atopica, Apoquel and Cytopoint all work by blocking part of your dog’s immune response. 

This is where conventional vets and holistic vets will part ways. Holistic vets are much more interested in restoring balance to the immune system … and avoiding the dangerous side effects of drugs.

Caution: Don’t stop your dog’s steroids cold turkey. Ask your vet how to wean him off the drugs gradually. 

How To Avoid Steroids For Your Dog

If your dog’s allergies are being treated with steroids, there might be a more effective – and safer – long term solution. 

Instead of using steroids, find a good holistic veterinarian to help you with your dog’s allergies. Allergies can be effectively treated with 

You can find holistic vets at and

As always, a good diet is the foundation for your dog’s health. So feed your dog the best diet you can … preferably a fresh, whole food, raw meat based diet

Nutritional supplements can work wonders for allergies … including Omega-3 fatty acids, colostrum, antioxidants, herbs, glandulars and enzymes.

RELATED: Try these home remedies for your dog’s allergies … 

The long-term effects of low vitamin D could be serious or even deadly for your dog. Don’t risk depleting your dog’s vital levels of vitamin D to manage his allergies when there are other, much safer ways to help him.


Skversky AL, Kumar J, Abramowitz MK, Kaskel FJ, Melamed ML. Association of glucocorticoid use and low 25-hydroxyvitamin D levels: results from the National Health and Nutrition Examination Survey (NHANES): 2001-2006. J Clin Endocrinol Metab. 2011 Dec;96(12):3838-45.

 Bischoff-Ferrari HA, Giovannucci E, Willett WC, Dietrich T, Dawson-Hughes B. Estimation of optimal serum concentrations of 25-hydroxyvitamin D for multiple health outcomes. Am J Clin Nutr. 2006 Jul;84(1):18-28. 

Martins D, et al. Prevalence of cardiovascular risk factors and the serum levels of 25-hydroxyvitamin D in the United States: data from the Third National Health and Nutrition Examination Survey. Arch Intern Med. 2007 Jun 11;167(11):1159-65. doi: 10.1001/archinte.167.11.1159. PMID: 17563024.

Charoenngam N, Holick MF. Immunologic Effects of Vitamin D on Human Health and Disease. Nutrients. 2020 Jul 15;12(7):2097. 

Mick Phillip J., Peng Seth A., Loftus John P.  Serum Vitamin D Metabolites and CXCL10 Concentrations Associate With Survival in Dogs With Immune Mediated Disease.  

Frontiers in Veterinary Science, Vol 6, 2019. 

von Essen MR, Kongsbak M, Schjerling P, Olgaard K, Odum N, Geisler C. Vitamin D controls T cell antigen receptor signaling and activation of human T cells. Nat Immunol. 2010 Apr;11(4):344-9. 
Rafael Zafalon et al. Vitamin D metabolism in dogs and cats and its relation to diseases not associated with bone metabolism. Animal Physiology and Animal Nutrition, January 2020.


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