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

Dog Cancer and Antioxidants…Time to Clear Up Confusion!

Updated: December 18th, 2018

Hi everyone,

The use of “antioxidants” is a charged topic in cancer care these days.  The holistic set tends to be “pro”, while the western vets and oncologists tend to be “anti”.  Let’s take a look from my favorite viewpoint…Full Spectrum care ( where we try to avoid biases that exclude useful things but gear evaluations towards real-life effects).

Here’s the problem: the use of the term “antioxidants” is totally muddying up our thought process in trying to give sound advice!  We need to totally eliminate this word from our discussion!! Yes, sounds a little weird.  So let me explain what I mean.

First, let’s widen back. What is an “antioxidant” anyway? Usually, people talk about the ability of a substance to help decrease the free radical activity in the body.  A free radical is what you get when you are consuming oxygen in body processes over time.

Free radicals tend to be harmful to living cells. There are many different types of free radicals but many contain  “used up” oxygen that was used for normal living processes or are the result of the reactions that use oxygen.  So that’s the oxygen connection to “antioxidant”.

The problem is this: most of the substances or vitamins that are classified as “antioxidants” have never even been shown to do that in a real-life body! (Check it out here)  And to top that off, many of the so-called antioxidants have “pro-oxidant” activity.  This means they are capable of increasing free radical effects.

Don’t go away mad, because there is more:  in many strategies in combating cancer, we want free radical generation.  Yes, we want free radical production, that was not a typo.  For example, we want free radicals to increase in cancer cells, so they die.  And we want to leave body cells unharmed in the process.  This is the theoretical basis supporting the use of radiation and some chemo treatments.

Some of the items in past or future postings on attack cancer cells in this way while leaving normal body cells unscathed.

Now I hope you are starting to see what I am talking about. It gets thicker though, so hang on, please.

There is major confusion surrounding cancer prevention, compared to cancer treatment.  Free radicals are one of the things that can damage DNA and contribute to cancer development.  That is one process, and the use of substances that block this process can help decrease the odds of getting cancer.  However, the use of the same substance at the same dose may not decrease cancer after it has developed (this is very frequently the case)!

For more helpful tools and information, get a copy of the Dog Cancer Survival Guide

So there are two entirely different instances…before a dog gets cancer, and once it has developed the disease.  Prevention and treatment….totally different!

People tend to use the word “antioxidants” as if they are the all same.  So “antioxidants”, all grouped together,  are “good” or “bad” in veterinary cancer care.  As if each substance, vitamin or therapy that has an antioxidant effect is the same as other, with the same effects.  Folks, this just wrong.

Each of the vitamins, enzymes, drugs, therapies and so on that are capable of quenching free radicals, or contributing to decreases in free radicals, is completely different.  They have different effects! Grouping them into a single functional category is a mistake.  The premise is flawed.

Talking about “antioxidants” and cancer care is like talking about “people” and the upcoming election.  Yes, we all have, oh, say, a beating heart.  True.  That is a similarity.  But can we make a statement that we will all operate the same at election time?  Of course not.  Just as you cannot group people with beating hearts in a single functional category just because they have a similarity, you cannot group antioxidants in a single functional category.

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Each is unique.

And to impress the point further, the use of a given substance that has an antioxidant effect may have good or bad interactions with other treatments.  The antioxidant effect may help or hinder in the context of what else is going on.

And what about all the other effects of the given substance? It will do a lot more than affect free radicals!

So, I believe we have been white-washing this entire area, perhaps out of a lack of information, or out of fear that we might worsen our already junky success rates with conventional care of malignant cancer.  Or maybe we have just been a little lazy, hard to say.

I will address specifics in this topic in future blogs, but I wanted to get this idea out there first.  This is our launching pad.

Best to all,

Dr Dressler


Leave a Comment

  1. Agata on April 27, 2013 at 2:01 am

    I wonder what is your opinion on microchips. My Labrador suffered from skin mast cell tumours for 9 years. He developed the first tumour 6 months after being microchiped and had countless surgeries to remove the tumours. Eventually it spread internally and killed him. I had always had a feeling that the reaction was to the microchip being a foreign material in the body. Non of the vets could give me a definite answer, they have never heard of it, but this doesn’t mean that it can cause cancer especially of this type which is a mast cell over- reaction. What is your opinion? Just in case I did not microchiped my new dog but it’s not easy to register a dog without a microchip.

    • Dr. Demian Dressler on May 9, 2013 at 3:37 pm

      I Agata,
      I have not seen a microchip induced cancer in dogs before…
      Dr D

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