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

Dog food and cancer: help fight this problem!

Updated: December 12th, 2018

In the last post I wrote about one of the issues in most commercial dog foods contributing to dog cancer: omega 6 fatty acid excess. This is a group of fats that are found in large quantities in corn products, vegetable oils, and meat products like tallow and lard, to name a few sources. Dogs in the wild eat lean meats (imagine an antelope’s body) and digested plant matter from the prey’s intestines. The diets we are feeding them currently are inappropriate, and in some ways harmful.

This omega 6 fat excess sets the stage for cancer development, stimulates cancer cell growth, and decreases the body’s natural cancer-fighting abilities.

Our dog’s bodies can better handle the omega 6 excess by providing them with another type of fatty acid that will decrease the harmful effects of too much omega 6. These are oils containing omega 3 fatty acids, which are found in high concentrations in fish oils. I outline this topic in detail in the upcoming book, but for the purposes of this discussion let’s focus on oil from sardines, menhaden, mackeral, salmon and so on. Cod liver oil is NOT a good source for omega 3 supplementation.

If your loved dog has a cancer at this time, you want to get as much omega 3 in him or her as possible. Start slowly and work your way up to large amounts over about 2 weeks to avoid an upset stomach. Give with food. For a dog about 60 lbs, you want about 18 grams of good quality fish oil containing omega 3’s. This usually means about 15-20 of the typical capsules daily, which is a large amount! For double strength caps, halve the dose. Adjust up or down for the size of your dog. The capsules can be popped and the oil mixed in food if your dog resists eating the capsules by themselves. Watch for digestive upset (vomiting, diarrhea, loss of appetite), and if so, stop and then later start with lower doses increased more slowly.

Krill oil is, in my opinion, the best option for supplementing fatty acids for a variety of reasons…

If your loved dog is not diagnosed with cancer and is on typical commercial food, I would have you begin an omega 3 fatty acid supplement at lower doses than those dogs with cancer. For a 60 lb dog, my opinion is a standard supplemental dose of roughly 4-6 grams of omega 3-containing capsules daily. Remember to start with low doses than work up over 2 weeks.

There is limited, theoretical evidence that you should stop these supplements 10 days before surgery as they may have mild blood-thinning effect. Do this as a precaution, to be on the safe side.

I will be giving many more practical tips to increase your dog’s health in upcoming posts!


Best to all,

Dr Dressler


Leave a Comment

  1. Dana on February 19, 2013 at 5:52 pm

    I believe it is diet and the water. First the commercial dog food is full of corn, probably GMO corn which has been proven to damage DNA when eaten. Then there is fluoride in the water which is a poison. Our dogs don’t have a chance with this kind of diet. We just lost our three year old American Bulldog to Osteosarcoma. Diagnosed Jan. 3 with a few growths on his shoulder and within a month had eaten the bone up. I had him on a cancer diet, k9immunity, transfer factor and omegas. Nothing slowed it down, it was awful. He was on taste of the wild after we rescued him but was raised on a food with corn as the first ingredient. He was already a year and a half when e got him.

  2. Megan Squier on January 24, 2011 at 4:15 pm

    Thank you for clearing up why most commercial pet foods are bad! My mother-in-law has raved about natural dog foods like Solid Gold and Evo for years but I never really believed her until I decided to adopt a dog from the local shelter. My MIL first started feeding her dogs natural foods after one of her dogs, Austin a Shetland Sheepdog died of cancer. Her vet, Dr. Moses from the Dover (DE) Air Force Base veterinary clinic told her that diet could have been the cause. I now find it quite interesting that both my parent’s Lab, Tippy, and their cat, Bubbles, both died of cancer too after being fed standard commercial diets. The food I’m feeding my dog contains no corn, wheat, vegetable oils or lard so hopefully, he will live longer.

  3. DemianDressler on August 8, 2010 at 11:48 pm

    Dear Robin, is there a question that I can answer for you? There is a book’s worth of advice that could be given…let me know!
    Dr D

  4. Robin on August 2, 2010 at 5:41 pm

    My 8 year old beagle has been diagnosed with hemangioscarcoma with masses affecting his entire liver. Apparently that is the site it originated in as well. So far, it has not spread and his liver function is good. He also has no weight loss and his appetite is good. He did bleed into his abdomen 3 months ago and his platelets are in the low normal range. He did have surgery and part of his liver was removed. I just started him on milk thistle, olive oil, and fish oil, but small amounts. His dry kibble is Natural Balance Venison and Sweet Potato, and I also cook for him organic chicken. Any advice would be greatly appreciated.

  5. Amira on May 26, 2010 at 6:20 am


  6. Jennifer on May 20, 2010 at 5:30 am

    My 10 year old lab was just diagnosed with a cancer lump near his splean. The vet has advised that it is too advanced to really do anything. He told me just to make him as comfortable as I can. He is a rather overweight dog but now I am having trouble getting him to eat. I was feeding him Iams but he refused to eat it at all. I am now feeding him pedigree, dry and canned. He is having problems with his joints because I am trying to wean him off prednisone so it is hard to get him any exercise. I have limited finances but I would like to do the best that I can for him. Is there anything I can give him to maybe make him feel a little bit better and spark his appetite? I really would like to improve his quality of life. Any advise as far as food and supplements? Thanks. Jennifer

  7. Denise on March 27, 2010 at 12:51 am

    Can fish oil or krill oil be fed in conjunction with drugs like Metacam, Tramadol, or Gabapentin?

    Also, is it alright to supplement with both fish and krill oils-perhaps one in the am the other at night?

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