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

Oleic Acid, Red Meat, and Mammary Cancer

Updated: May 15th, 2024

As readers of The Dog Cancer Survival Guide know, dogs who have not been spayed by their fourth heat run a higher risk for mammary cancer. (Spaying offers its own risks for other types of cancer, but that’s another post.)

But other factors can contribute to canine mammary cancer, and some of these are not as well known. It turns out that, as in humans, diet is a very important part of cancer development.  It is estimated that diet accounts for about a third of human cancer cases, and I believe diet will be getting more attention in the veterinary profession as time goes on — if only because the general public seems to intuitively understand the connection between diet and cancer already.

Many readers of this blog cook for their dogs, and I’m sure some are thinking that this is the ticket. But avoiding commercial dog foods is not the only answer. The relationship between diet and cancer is complicated — in particular for mammary cancer.

A rationale is often made that a home made diet should mimic that of a wild dog or wolf.  In particular, it should be raw. I’m interested in this and talk about it at length in my book, including the use of human-grade food ingredients in dog’s meals — but we should all realize that the jury is still out on this.

It’s complicated… so let’s take a closer look. Let’s look at red meat. Do dogs in the wild consistently get red meat?  Of course not.  They are unable to kill large prey every day.  Smaller dogs are even less likely to consume daily red meat in the wild as it is harder for them to bring down large game.

And the truth is that beef today is largely fed corn, as opposed to previous decades in which herds of cows grazed wild grass.  This changes the fats in the meat. Red meat is not what it used to be.

It turns out there are links between continual feeding of home made diets that have a lot of red meat (beef or pork) and little chicken: obesity, but also canine mammary cancer. One of the central players seems to be a certain type of fatty acid called oleic acid, which was found in higher levels in the dogs with mammary tumors.

As a matter of fact, oleate (similar to oleic acid) was found to slow down the beneficial process of apoptosis in human breast cancer cells.  Apoptosis is the genetically programmed, beneficial cell death of cancer cells (this is where the name Apocaps came from, by the way).  Less apoptosis, less cancer cell death, and more cancer cells.

So what’s the take home message?  Don’t feed your female dog red meat every day. Rotate other protein sources such as chicken and fish. Rotate in beef and pork perhaps every 1-2 weeks (The Guide has specific directions on how to use home made and/or commercial foods for dogs with cancer).   This is particularly true if your dog is overweight, is not spayed, or already has developed mammary nodules.


Dr D

Leave a Comment

  1. Fabrizio on June 22, 2012 at 2:47 am

    I agree with Mark.
    I do not think the Oleic acid is the culprit.
    Rather the fact that Omega 6 and Omega 9 fats are present in a much higher ratio to Omega 3 fats in the animals raised today.
    Feeding them with fresh grass rather than flours makes a huge difference on the lipid profile of their meat.

    Whit this respect we might say that it is not the high intake/content of Oleic acid that is problematic, but rather the low intake/content of Omega 3 (and so the high Omega6-9 to Omega3 ratio).

    The connection between Oleic acid and cancer is very controversial, with lots of publications asserting its beneficial effect towards Mammary cancer in humans and animals.
    Mainly due to its effects on “Her-2/neu” genes that play an active roles in breast cancer progression in almost one third of all breast cancers.

    So, I would be extremely carefull when saying that Oleic acid may be harmful.

  2. Mark on June 21, 2012 at 10:23 am

    Don’t blame old time foods for new diseases… I’d lean more towards the idea that the way meat is raised today is the culprit, if it really even is the culprit, not the fat itself.

  3. Game on June 20, 2012 at 5:53 am

    This book would make a wonderful gift for any family, friends, etc who are dog lovers. I will put this on my Christmas list for next year.
    Unfortunately, I also found this book too late but realize the tremendous benefits of having the information.
    My gift to my other dogs, after we lost our little peek OLGA to oral melanoma, is to follow what Dr. Becker recommends, and try to feed a whole food, raw food diet. There is a raw dehydrated food we use, along with puréed raw vegetables, and Orijen kibble. Our dogs beh for veggies now, they love apples also. You can always sneak blueberries etc. into their veggie purée.
    Thanks Dr. Becker, for doing what other vets haven’t done.

  4. Rachel on June 19, 2012 at 12:13 pm

    Beef and Pork contain the fatty acid called oleic, however as I live in Australia I have easy access to kangaroo meat which is very low in fat and high in protein. I have found this an excellent alternative and my two dogs love the taste. Kangaroo meat contain omega-3, CLA (Conjugated Linoleic Acid) which has antioxidant properties, high levels of iron and zinc and B-group vitamins, riboflavin, niacin, Vitamin B6 and Vitamin B12. It’s a bit of a super meat and much better for humans and dogs than beef or pork. I also add tumeric to my food mix as it has cancer fighting properties, partically for bowel and stomach cancers and my dogs seem to love the taste, although it makes there food look bright orange.

  5. hiedifrancis on June 19, 2012 at 5:37 am

    On June 3, I lost my 8 year old Boston Terrier (Lucy) to metastasized MCT. She had her first tumor in 2007, her 2nd in 2010 then in Dece 2011 she had 5 tumors removed. January 2012 her cancer metastasized. While doing my own research I found a new report that MCT may be a secondary cancer to Melanoma. I believe this article as Lucy had an odd patch of skin on her back before 2007 and the vet never would look at it. When her cancer metastasized the patch tripled in size (about 3 inch in diam.) What do you think about MCT being a secondary cancer to Melanoma? Puppy sun block will be used with my next best friend. Thank you, Hiedi P.

  6. Susan on June 19, 2012 at 2:55 am

    Hi Dr. Dressler,

    I lost my 12 year old mini poodle to invasive inflammatory mammary carcinoma a few months ago. Within 2 months, her tumors literally grew from a small nodule to several large inflamed tumors along the mammary chain. I never fed her beef. She ate a combination of cooked chicken, salmon, eggs, and premium dry dog food. However, she was not spayed until she was 5 years old and was vaccinated each year. She was always very healthy until these last couple of months. Any thoughts about why her disease would have progressed so quickly?
    Could anything have been done for her ? Thank you.


  7. Carly on June 15, 2012 at 7:27 pm

    Hi Dr. Dressler,

    How much food from your cancer diet should I feed my ~11 lb dog with hemangiosarcoma? He is used to eating 2x a day. I’ve read your book and the diet book, but haven’t seen anything on how much of the recipe to feed dogs (I may have missed it as I have been reading a lot in the last week since the diagnosis). Any help would be greatly appreciated. Thank you!


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