Several years ago, I started testing vitamin D levels in the serum of my dog and cat patients. What I found in pets that were on “balanced” commercial diets surprised me.
Over 65% of my dog patients and 55% of my cat patients were testing insufficient or low on vitamin D.
Many of the pet owners, who were informed of their animal’s low vitamin levels, immediately jumped to the conclusion that vitamin D in pets is primarily created through exposure to sunlight. In humans, that is the case. But, it turns out that in our pet dogs and cats, their thick hair coats prevent sunlight absorption, so vitamin D is obtained through the diet.
Foods, including beef, liver, eggs, salmon and mushrooms contain vitamin D.
A healthy diet for dogs and cats should contain plenty of organ meat, rich in vitamin D, but even if the vitamin D is present in the diet, the gastrointestinal microflora (the microscopic bacteria and yeast organisms in the bowel) and the digestive enzymes need to be present to help with absorption of nutrients.
Unfortunately for our pets (and us), the GI microbiome is being impacted negatively by toxins, herbicides, pesticides, insecticides, heavy metals and many other chemicals. They impact gastrointestinal lining health, the microbiome and our nutritional status for all nutrients. The presence of vitamins doesn’t mean our bodies and our pets’ bodies are absorbing and utilizing the nutrients.
Misconceptions about vitamin D
About 10 years after I started measuring vitamin D and supplementing pets regularly, I attended a national vet conference. A veterinary nutritionist from a respected university was speaking about nutritional deficiencies in pets. Another attendee asked about measuring and supplementing vitamin D, and the speaker laughed and stated, “We don’t measure vitamin D or supplement, because there are no pets in this country who are low in vitamin D”.
Many members of the veterinary community, including nutrition experts, don’t recognize vitamin D testing as important, and consequently, they do not identify a real problem in pets. And the statements made by these nutrition experts create misleading and incorrect info that circulates on the internet and to pet owners.
Importance of vitamin D To health
Vitamin D has many roles in the body and is involved in over 300 metabolic pathways to support immune function, bone, tooth and skin health, hormone balance, and anti-cancer pathways (when working with the mineral magnesium).
Vitamin D is vital in its role in aiding calcium and phosphorus absorption through the gastrointestinal tract. Without adequate vitamin D, the calcium and phosphorus in the bones and teeth will be lost to support bodily functions. You will not notice your pet losing these levels, because blood testing does not demonstrate mineral loss. Pets’ bodies (and our bodies) will continue to maintain blood levels of minerals, even when severe osteoporosis occurs. Pets can suffer from mineral loss from bones, tendons and ligaments.
There are mineral analysis tests that can identify levels of calcium, phosphorus and magnesium, but most veterinary practices do not offer this testing.
In addition to vitamin D testing, I perform mineral analysis testing, and find that over 90% of all pets have shockingly low calcium and magnesium in their tissues, in spite of normal blood levels.
Vitamin D also is involved in immune health and musculoskeletal functioning, as well as the body’s control of inflammation, pain, immune functions and anti-cancer monitoring.
Would it be wise to supplement vitamin D, with so many pets testing low?
Supplementing vitamin D without knowledge of your pet’s levels of vitamin D is not wise. Over-supplementing and high vitamin D levels are very detrimental to your pet’s kidney health and vitamin D toxicity is a danger.
Currently, I am finding more pets than ever testing high on vitamin D levels. This has occurred since the time of COVID. My theory is that many pet food manufacturers are trying to maintain high protein levels and cut the cost of muscle meat by adding excess levels of organ meat or may be adding extra vitamin D sources to the pet foods. Because regulatory agencies don’t require pet food companies to test vitamin levels in individual batches of pet foods, unless pets start dying from toxicity, monitoring will not occur.
How can pet owners learn about their pets’ vitamin D levels?
A simple blood test can be run which monitors D levels in the serum. A follow-up blood test is recommended 8-10 weeks after initiating therapeutic supplementation – I recommend a liquid oral pet-specific supplement.
If levels continue to be low, I may recommend adding magnesium and a digestive enzyme. Frequently, I look at abdominal ultrasounds to evaluate bowel wall health in pets with persistently low vitamin D. In some cases other hormone testing, including parathyroid testing is also recommended.