Most people know Vitamin D helps build strong bones.

What most people don’t know is that it also plays a huge role in immune strength, cellular health, inflammation, and long-term disease prevention.

And in dogs?

Vitamin D is even more important – because unlike humans, dogs can’t make it from sunlight.

Let’s make this simple.

Why Vitamin D Is Such a Big Deal for Dogs

Vitamin D doesn’t just float around doing “bone stuff.” It’s involved in almost every part of the body:

> It supports the immune system

> It helps reduce inflammation

> It influences how cells grow, repair, and die

> It even helps turn “healthy” genes on and “unhealthy” genes off

Your dog’s cells have Vitamin D receptors all over their body – which means Vitamin D is constantly giving instructions that keep those cells functioning properly.

When levels are low, the system struggles.

Dogs don’t get Vitamin D like we do

Humans make Vitamin D through the skin.
Dogs can’t.

They have to eat it.

In the wild, wolves and big cats get Vitamin D naturally by eating prey animals – especially the organs and fatty tissues where Vitamin D is stored.

Modern pet diets, especially kibble, don’t come close to replicating that.

This is one reason Vitamin D deficiency is surprisingly common in household pets – even “healthy” ones.

What low Vitamin D has been linked to

Research (in humans and animals) has connected low Vitamin D levels to a wide list of health issues, including:

> Inflammatory bowel disease

> Heart and kidney disease

> Autoimmune diseases

> Certain cancers

> Chronic inflammation

> Infectious disease susceptibility

> High blood pressure

> Diabetes

Basically, if inflammation is involved – Vitamin D probably is too.

And if you’re wondering whether there’s anything inflammation doesn’t affect…
The answer is: no. Every major disease process starts with inflammation.

Even “healthy” dogs are showing low Vitamin D

Studies have found:

> Many healthy dogs are still Vitamin D insufficient

> Neutered pets often have lower Vitamin D levels than intact pets

> Some breeds absorb Vitamin D differently

This means Vitamin D status isn’t just a “sick dog issue.”
It’s something many dogs quietly struggle with long before symptoms show up.

Why this matters so much

Dogs’ bodies compensate for a long time before they show obvious symptoms.
A deficiency can be building for months (or years) before you see anything on the outside.

Testing Vitamin D before disease develops gives you the chance to correct imbalances early – when it’s easiest to help and hardest for disease to take hold.

Prevention will always be easier than treatment.

Testing Vitamin D: Here’s how it works

The good news? Testing is now easy and reliable.

Dr. Pam uses a simple fasting blood test to measure 25-hydroxy Vitamin D – the form that tells us your dog’s actual status.

You’ll receive:

> Your dog’s Vitamin D level

> A clear recommendation (whether to supplement or not)

> A follow-up plan to get levels into a healthy range

After supplementation begins, levels are typically rechecked in about two months, then annually once stable.

Why you should never supplement without testing

Vitamin D is a fat-soluble vitamin, which means:

> Excess can build up

> Dogs can store it in the liver

> Too much can be harmful

> This is not a vitamin to “guess on.”

> Testing first ensures your dog gets exactly what they need – no more, no less.

Absorption matters too

Dogs fed kibble often struggle with digestion and bile release, both of which are needed to absorb Vitamin D properly.

That’s why Dr. Pam evaluates the following before choosing the right supplement and dosage:

> Diet

> Digestive health

> Bile flow

> Overall nutrition

The big picture: why Vitamin D matters for lifelong health

Every cell in your dog’s body depends on nutrients to function.
Give those cells what they need, and you build resilience.
Deprive them, and dysfunction starts to stack up until symptoms eventually show.

Vitamin D is one of the key nutrients that keeps those systems working the way nature intended.

Getting it right now makes a huge impact on your dog’s health later.