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Featuring Demian Dressler, DVM and Sue Ettinger, DVM, Dip. ACVIM (Oncology), authors of The Dog Cancer Survival Guide

The Two Sides of Sunlight and Dog Cancer, part 2

Updated: January 10th, 2019

In the last post, we examined those cases where a dog lover might want to protect dogs prone to certain skin cancers with sunscreen and indoor living.

However, these are the minority.  The vast majority of dogs actually benefit, in a real way, from some direct sunlight.  Here’s my argument…

Sunlight exposure in people is  linked to lower rates of prostate cancer, breast (or mammary) cancer, lung cancer, ovarian cancer, colon cancer and more.  In total, 18 different types of cancer were found to have significantly lower rates with sunlight exposure. 18! That’s a lot.



There is now a movement, at least from those in the know, for public health recognition of the beneficial effects of sunlight on cancer development.  This means the human database of medical info needs to be updated. Those in the know hail from SUNARC, or the Sunlight, Nutrition and Health Research Center in San Francisco. Read more here.

But what about dogs?  Is there a link?

Dogs are used as models for human cancers now frequently.  As a matter of fact, the molecular similarities are huge.  The National Cancer Institute formed The Comparative Oncology Program (COP) a few years back, which is a research program using dogs as models for human cancer due to their similarities.

Given all of this, I have drawn medical information from the human research and applied it to dogs to good effect.  This is another area where dog lovers can do even more for their pets.

How does sunlight work to decrease cancer rates? The way sun is believed to help is by boosting active levels of vitamin D in the body.  The amount and efficiency of vitamin D activation by the sun is much higher than taking vitamin D3 pills by mouth.


For more helpful tools and information to help your dog with cancer, get a copy of this informative guide


On top of it all, what dog does not like to be outside for a while?  Talk about a life quality positive!

Nobody has thus far determined exactly how much sun is needed.  It varies in human literature based on ethnicity and location.  But it is clear that not a lot is needed.  Some estimates are about 15-30 minutes just a few times weekly.

This amount is enjoyable and tolerable for almost any dog (except those loungy couch potato canines, you know who you are!)

A word of caution:  some dogs can get hot and even get heat stroke in direct sunlight for prolonged periods.  The dogs who are especially at risk are those with longer coats (like the Samoyed, Husky, Chow, etc) or those with “pushed in” faces (brachycephalic breeds like Bulldogs, Pugs, Pekinese, etc.).

Always give your dog access to cool water and shade, and if your dog has a long coat or a “pushed in” face,  it is best to be there with your pooch to keep an eye out for overheating.

For more on activating Vitamin D, check out The Dog Cancer Survival Guide.

Best to all,

Dr D


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