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

Cancer spread, Flax and Dog Cancer

Updated: December 26th, 2018

Flax is one of the oldest crops known to man.  Even the ancient Egyptians cultivated it extensively.

These days, we don’t see it around much, except in health food stores or the supplement shelves in grocery stores.

So why am I writing  about this stuff?  Well, flax has some handy properties that someone  who loves a dog with cancer might want to know about.

You can find more about natural compounds and their anti-cancer effects in my dog cancer book.


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A little background, if I may.  The seed part is most commonly used in nutritional preparations, and you can also find oil.  Don’t bother with the oil.  It does not have the good stuff you want for this purpose.  You want the ground seed itself, specifically the lignan portion of the seed.

Lignans provide strength to plant cells and make them water-tight.  They are overall quite safe.

The lignan that seems to be the main player for our purposes is secoisolariciresinol (like some of the readers, I probably will avoid trying to say that twister).

Not that this is active in the body- it’s not.

However, this stuff gets broken down by the microbes in the intestine to a couple of active products in the body (eterolactone and enterodiol).  These two have real effects that we like.

These phytoestrogens are the players of interest.



Flaxseed slows the metastasis of of certain kinds of  breast cancer cells that were put in mice by 45%.  Here is the abstract.

Flaxseed slowed the growth of melanoma cells in mice significantly as well.  Check it out for yourself here.

There is also a slew of data on human anti-cancer diets, and flax is one of the ingredients that helps in these diets.

An average dose for a large dog would be roughly 16 grams (approximately half an ounce) of ground flax seed per day.  Kind of a big scoop, but if your loved canine is eating well, it would likely be tolerated and maybe even gobbled up happily.

I would definitely consider it for the melanoma dogs, and for those pooches with  angry mammary cancers.  Discuss with your vet and oncologist of  course.

The scientific scrutinizer set will bring up the estrogenic effects of these active  phytoestrogens from flax.  Yep, kind of like soy and yams, there are some estrogen (female hormone effects).


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Why does it matter? Well, if your dog is spayed and fairly young, there is not much estrogen floating around.  Conventional veterinary doctrine states that early spay is best, and thus so is the removal of these baaaaaaaad female hormones from those removed ovaries. You put some flax lignan in the dog,  you get baaaaaad estrogens again.

I disagree (in case you didn’t guess). First, young dogs rarely get melanoma or breast cancers. So the effects of these plant estrogens would not be over a typical lifetime, just towards the end of life.

Next, the most aggressive breast cancers in dogs do not usually have the estrogen receptors on their cells (the “lock” that the estrogen “key” fits it, that can turn on growth). No lock for the phytoestrogens to turn on cancer cell growth means no cancer stimulation effect of the flax lignans.

Finally, the dogs with breast cancer are often not spayed. These dogs have natural estrogens in them, which block  estrogen receptors in cells.  Thus the phytoestrogen key cannot fit in the lock.  It already has a key in it.

Anyway, many of you may have gotten bored by now, so I’ll stop.  Sorry about that!

Take home message?

Flax is generally safe and can help. We want to attack canine cancer on a lot of levels, like a daisy cutter bomb. This is another way to do it.

Caution is warranted in diabetic dogs  (may lower insulin levels needed) and in dogs having or recovering from surgery (some theoretical “blood thinning” effects).  Please discuss with your vet or oncologist.

Best to all,

Dr D


Leave a Comment





  1. Pat Sims on February 13, 2021 at 5:56 am

    I have 8 year old beagle. She has had diarrhea for over 3 months. Otherwise seems fine. She is eating and drinking. But now has started eating the poop. I have been to vet numerous times. Had X-rays and blood work nothing showed up. . First time was told she just had virus. So I changed vets. I don’t want her suffering but the new vet said he felt a mass and probably cancer. Will not know for sure unless i do an ultrasound which is $500 more dollars. She has been on Flagel 3 times. And Amoxicillin. No change. I lost my husband and she is all I got. I can’t make myself go up there and have her put down. Any suggestions. I am only trying to save my dog. But do not want to be selfish if she is in pain. Which she seems to be when she goes. I am on SS and do not have any more money. I have read about Flax oil and wanted to see if that help her. She is the sweetest thing in the world. Thanks for any help!

  2. GWEN CREW on November 15, 2018 at 5:32 pm

    My English Setter 8 years old, just had breast cancer surgery i. August 2018, mammory glands 2 removed masses and spayed at same time. Her skin is sensative now, shedding, ect. I was was going to try flax seed meal in her food or buy supplements idk what do you think? I read your article is she safe witb flax if she is spayed. She still has some glands in her
    Breast

    • Molly Jacobson on November 19, 2018 at 1:05 pm

      Thanks so much for your question, Gwen. I’m not a veterinarian, and it’s probably best if you ask your own vet what they think. If the cancer has estrogen-sensitive properties, they might want to get omega-3 fatty acids from another source. Dr. Dressler usually recommends fish or krill oil, and you can read about it in the chapter on diet in his book. In many dogs, those oils can be helpful.

  3. […] The Budwig Diet is popular in the treatment of cancer and includes cottage cheese and flaxseed.  Flax slowed the growth of breast cancer and melanoma. Read more here. […]

  4. Carolyn Duncan on February 6, 2012 at 6:11 pm

    My over 10 1/2 year old mixed breed pup, Bess, was diagnosed with bone cancer in her left front leg in December 2011. We were told amputate to manage the pain and then possibly chemo/radiation. We haven’t done either. He did eliminate almost all carbs and started her on a raw chicken diet with flax seed oil, cottage cheese (tho’ it’s not organic) with a handful (1/4 cup) of no-carb/filler protein kibble and some vegetables and occasional teeny greenies (if she seems particularly hungry).
    She takes pain meds 3 times a day; plus we give her anti arthritis tables in addition to her thyroid pills.

    She plays, barks, eats, does her business as she limps around the house on all threes! I haven’t taken her back to the vet since December; should I be monitoring the cancer progress?

    Also, I am confused as to how much cottage cheese along with her raw diet to give her. She is on the heavy side and according to the raw diet direction she should be getting 2% of her weight in food…so, I using 50 lbs because that is what she should weigh. Therefore, she gets 8 oz of chicken twice a day.

  5. Denise on March 27, 2010 at 8:55 am

    Isn’t flax also high in omega 6 though?

  6. eryn on February 25, 2009 at 8:38 am

    I was told to do the budwig protocal separate from the meal and any other vitamins or supplements. My dog has nasal cancer and I recently added this as two snacks for him.

  7. patricia1594 on February 24, 2009 at 9:29 am

    As per the Budwig diet, I have been blending 1 part cold pressed flax oil to organic cottage cheese as an additive to my dogs food. My 11 1/2 yr. old cocker spaniel had a 13 pound chondrosarcomaa removed from her abdomin. See photobucket.com/patricia1594 for tumor photo.

  8. Rachel Simpson on February 18, 2009 at 2:34 pm

    I’m a bit confused. I have a bottle of flax seed oil, which I have been adding a bit to my dog’s food to supposedly help her, in particular, to fight off any possible cancer cells. The bottle claims that the product is “Lignan Rich” but this article states that the oils are not. How do I know for sure??

  9. maltese mom on February 17, 2009 at 11:27 am

    Thank you Dr. Dressler, this was very helpful.

  10. Dog Hair Dog Hair on February 16, 2009 at 12:44 pm

    Very informative article. Thank you very much for sharing.

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