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

Glutamine, Immunity and Canine Cancer

Updated: October 10th, 2018

Cancer is a whole-body disease.  When we think about cancer, many times we tend to look at it as if it were just a single growth.

A single growth is called a tumor.

We can see tumors, either on the body of a loved dog or with a tool to see the inside of the body.  Many times a tumor is visible with an X-ray, ultrasound, MRI or a CT (“cat scan”).

Because of this we will automatically assume that the tumor is the only thing going on in a dog with cancer.

The problem is that there is often more going on than just a tumor.  Tumors happen in a body, and tumors affect that body.

By supporting the body, we can get an edge in fighting dog cancer.  This area is sometimes ignored in dogs receiving conventional cancer care.  Since we want to use every tool at our disposal to fight cancer, which is very formidable, we need to focus on body support. There are many ways to do this that are covered in detail in The Dog Cancer Survival Guide.

One of the things cancers frequently affect is the immune system. Cancer can suppress the immune response. This happens in up to 70% of cancer patients.  A healthy immune system is needed not only to help the body fight infections, but also to fight the cancer itself.

Cancers are often able to send out chemical signals that suppress the white blood cells directly.  On top of this, patients with cancer experiences stress.  Many times this can be psychological, and sometimes the body itself reacts to the cancer by releasing stress hormones.

When these things happen, the immune system is weakened and cancer growth is stimulated.

So it makes sense that we would want to support the rest of the body that is fighting the cancer.

There are different ways to help support the immune system.  One of them is by providing a four-legged family member with glutamine.

Glutamine is an amino acid.  Amino acids are the building blocks of proteins.

Cancers cause a glutamine deficiency in the body.

Glutamine is special because it helps block the effects of the chronic stress hormones on the immune system.

On top of this, glutamine actually stimulates the immune system directly.

Finally, glutamine can help lessen the digestive upset and side effects that can be seen sometimes with chemotherapy and radiation treatments.

There has been some confusion about whether glutamine helps or hinders cancer patients.  Old information suggested glutamine might cause cancers to worsen.  This has been debunked.

Glutamine is considered a safe supplement for dogs.  However, there is some theoretical evidence that it may reduce the effects of seizure control medications, and therefore to be safe should be avoided in dogs with seizure problems until this is studied specifically.

Apocaps is a supplement to help normal support life quality and longevity of dogs in my hospital which includes glutamine.

As always, before making any change in your dog’s care, you should consult with your veterinarian.


Dr D

Leave a Comment

  1. Betsy on May 19, 2022 at 6:31 am

    I’ve read about glutamine being a food source for cancer. Can you help explain why l-glutamine is included in the apocaps supplement? Is there a difference in consuming dietary l-glutamine vs. how the body creates glutamine that the cancer cells then use for fuel?

    I’ve been confused on this topic. Thanks for any clarification!

    • Molly Jacobson on June 13, 2022 at 2:30 pm

      According to Dr. Dressler, the amount in Apocaps is very small, and it is there because it’s part of the overall formula. There aren’t any fillers in Apocaps — every ingredient has a very specific (and sometimes multiple specific) role to play. Glutamine in large amounts may be problematic in some cancers — brain tumors come to mind — but glutamine is an amino acid, and is present in MANY foods, and dietary levels are not a concern.

      In fact, the idea that glutamine “feeds cancer” has been debunked in the link Dr. Dressler included in the article above:

      Here’s the relevant result listed: “A large body of evidence in vivo suggests that supplemental glutamine does not make tumors grow but in fact results in decreased growth through stimulation of the immune system. When given with radiation or chemotherapy, glutamine protects the host and actually increases the selectivity of therapy for the tumor.”

      In other words, glutamine supports and stimulates the immune system, and giving it during cancer treatments may not only help the body, but actively increase the effectiveness of cancer therapies.

  2. Janette Hinkley on April 9, 2019 at 10:04 am

    will the glutamine in Apocaps prevent a dog on a ketgenic diet like being used at Ketopet sanctuary from getting into ketosis?

    • Molly Jacobson on April 9, 2019 at 2:34 pm

      Hi Janette! We don’t make Apocaps here at Dr. D’s book publisher but I do know that the amount of glutamine is tiny. I wouldn’t think that it has any impact on blood sugar at all. You can always ask the folks at, of course.

  3. Maggie Lee on May 21, 2011 at 7:17 pm

    Dear Dr. Dressier,

    My basset hound Tak Jai has suffered from soft tissue sacroma. His vet has precribed L-Glutamine 1.5g daily to him. I would like to know is it safe?

    Thank you very much for your reply in advance.


    • DemianDressler on May 25, 2011 at 9:38 pm

      Dear Maggie,
      Sorry to hear about your Tak Jai.
      L glutamine should not be used in dogs with seizure disorders, on seizure medication, or having brain disorders of other kinds. As far as we know, these are the main issues seen with the supplement. Of course, every dog is different, and your vet should give you the info…
      I am hoping you are also giving the other proper supplements under vet supervision too (apoptogens, immune support, and so on)? And of course, diet? These are discussed in the Guide. and also you can find more info by searching the blog using the search bar in the upper right of this page.
      I hope this helps
      Dr D

  4. Carolyn on March 4, 2011 at 4:16 am

    My 14/5 Dalamatian Victoria has been diagnosed with a mass in the right nostril
    bridge of her nose, and a 1cm. tumor at the front of her brain. She is taking
    Phenobaritol, after 4 seizures. approx. 4weeks ago. She started on 60mg. and then reduced to 45mg. because of lethargy, falling and slipping. After a blood
    test my vet, put her back up to 60mg. She continued to have the same problems
    so the neurologist put her back to 45mg. AM. and 60mg. PM. Victoria is very
    comfortable in the day, but at night she is panting and wandering round and round. I give her 25mg. of metacam at aout 12am. with food, but this does not help, and she does not settle down to about 4:30am. I need someone to give the right advice, as I am not getting much sleep. I just want my little girl to be comfortable, and I am not ready to put her down. I would like biopsy done to see what kind of beast this is. I have spent a lot of money so far on vet bills, and
    no one has cured Victoria or helped to shrink this beast in her head. I am feeding her canned Nutro chicken chunks, along with lots of broccoli.. Victoria always liked her vegetables and her fruit especially melons. I am not giving her too many fruits as I have heard that cancer thrives from sugar. I have been giving her about 2tablespoons of cottage cheese with flax seed oil. I also give
    Victoria ground flax seed on her food.
    Thank you for any suggestions
    Carolyn Saumur

  5. Dr. Dressler on May 22, 2010 at 5:17 pm

    Dear Tracy,
    Good question. When gathering data and formulating Apocaps for my patients, I chose natural substances that have effects that are similar to those of the NSAIDS. For this reason I prefer to use a lower dose of either the Apocaps or the NSAID if they are used together to avoid digestive upset. If one of my patients benefits from a prescription NSAID, I use 1/4 to 1/2 dose of Apocaps on that day, or give the NSAID by itself. I was surprised to find that after a few weeks on Apocaps, many of the dogs in my hospital needed less, or in some cases no NSAIDS. Of course, please make all decisions about your dogs care under professional supervision. Be in touch,
    Dr D

  6. Shawna on May 21, 2010 at 6:55 am

    I would advise using glutamate with caution – under the supervision of a knowing vet… Glutamine can be converted to glutamate (an excitotoxin) and can cause brain damage. A quote from neurosurgeon Dr. Russell Blaylock – wrote the book “Excitotoxins: The Taste that Kills”.

    “This is the major source of glutamate within the brain. Excitotoxins are usually amino acids, such as glutamate and aspartate. These special amino acids cause particular brain cells to become excessively excited, to the point they will quickly die. Excitotoxins can also cause a loss of brain synapses and connecting fibers. Food-borne excitotoxins include such additives as MSG, aspartame, hydrolyzed protein and soy protein extract.

    In two recent studies it was found that the amount of glutamine in the brain could predict the brain damage seen both in pediatric brain injuries and brain damage secondary to seizures. Adding large amounts of glutamine to the diet increases significantly brain levels of glutamine and, hence, glutamate. Another study found that by adding glutamine to the diet of animals exposed to another powerful excitotoxin called quinolinic acid, brain cell damage was increased significantly. Quinolinic acid is known to accumulate in the brain in most cases of viral brain infection as seen with HIV dementia and viral encephalitis.”

    • Dr. Dressler on May 22, 2010 at 4:35 pm

      Dear Shawna,
      Thanks for the information. An important consideration in the glutamine discussion is the topic of dose. Certainly the statement that glutamine can cause brain damage as a generality must be make with caution. Glutamine at the usual doses prescribed in veterinary medical texts, including the professional standard Plumbs, do not indicate that the doses prescribed cause brain damage. When taken in high enough doses, many substances could be said to have the same effect, including everyday items like table salt. Although it is always prudent to contemplate the dangers of any treatment for a loved family member, we need to temper fears in relation to side effects with considerations including dose amount and frequency of administration. I feel your comments do highlight an important issue, although dose considerations are part of this analysis. Thank you for your contribution- it is discussions like these that really flesh out the value of having a community that cares!
      Dr D

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