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

The Premature Frenzy: Resveratrol

Updated: November 12th, 2019

Ever since Dr. Oz mentioned resveratrol on Oprah, the media has anchored this substance into the minds of dog lovers across the country.

Granted, resveratrol is very interesting.  And the anti cancer effects of resveratrol are quite interesting too…but mainly in test tubes and petri dishes.

If one were to use this as the basis for a recommendation, we would be slinging thousands of supplements and curing cancer left and right.

Here is the basic issue: when a dog lover is trying to find out what to use for their four legged family member, there are too many options to choose from.  Since there are few published papers comparing real life cancers in dogs on different supplements, one has to be able to consider different technical factors to come up with top contenders to try.

Safety, trials in dogs, trials in lab animals, trials in people, trials in test tubes and petri dishes, activity when given by mouth (as most dog lovers don’t do injections) and manageable oral doses are considerations.  These were all used as criteria to weed out supplements with lower probabilities of helping dogs with cancer in The Dog Cancer Survival Guide.

If a supplement only has published or studied benefit in test tubes but not in real life bodies, it should not be recommended (at least, not yet).

Even if we have lab animal studies on cancer supporting the use of the supplement, I advocate a rotation between different ones since we just don’t have real life trials, in real life dogs.

Resveratrol, along with a huge number of others, looks great but not (yet) in real life dogs with real life cancers that have already developed.

I would love to see any actual studies in dogs, or even laboratory animals, using resveratrol as an anti-cancer agent. Yes, there are studies out there using test tubes and petri dishes (did I make that point already?), but where are the in vivo (“in life”, or in living bodies) data showing the anti-cancer effects (not longevity, not hypoglycemic, not anti-oxidant or anti-ischemic)?

Remember, we need to look at data where the stuff is given by mouth, not by an injection.  There are a few publications in lab animals where resveratrol shows benefit, but it was injected.  This does little good as resveratrol injections are not generally available at this time to vets.

I should point out that there is a study in mice, in all fairness, that showed a decreased rate of spread for colon cancer when resveratrol was given by mouth.  This is a good thing, and likely reflects the fact that the substance was able to contact the tumor cells directly after being taken by mouth.  So, this would be one application of resveratrol in dogs that could be considered.

I would sure like to see some safety data however.

The confusion escalates when all of these other studies involving cancer prevention or involving injected resveratrol, which are not relevant to the question of a current cancer patient (and we are not talking about cancer prevention here folks), are tossed around as if they support resveratrol’s use for existing cancer. When taken by mouth. For existing cancer. Existing cancer.

The reason I am repeating these phrases, and being a bit flippant, is that there is so much hype using irrelevant studies to support resveratrol’s use in patients with existing cancer.  It has driven me a bit batty!

On top of this, resveratrol, at least in humans, is largely utterly destroyed by enzymes lining the intestine and in the liver after being absorbed.  If a dog (or a person) takes a pill, it goes down into the stomach and intestine and the stuff in the pill gets absorbed into the blood.  Then it goes to the liver for processing, then to the rest of the body and ultimately to the cancer cells. If it gets caught in the liver, and inactivated, it is done for.

The best way to get resveratrol in the blood at this time is by an injection (by passing the intestine and liver) or by holding a lozenge under the tongue, neither of which are likely to happen in a dog cancer patient.  No IV resveratrol is available, and dogs don’t suck pills.

Having said that, a new resveratrol delivery system is in the pipeline. This is quite exciting actually. SRT501 is coming, and this drug is a form of orally bioavailable resveratrol. Now that is something to create some hype about!  This one has data that shows it actually gets to concentrations (in real life bodies) that are in the ballpark of what we are shooting for!

SRT501 is a ways off (years). But don’t lose hope, you never know what might pop up next in the resveratrol story.

So, resveratrol has potential merit in real life dogs with real life cancers.  Just not quite yet, in my opinion.


Dr D

Leave a Comment

  1. Philip Caldwell on January 26, 2010 at 4:08 pm

    Dear Dr. D,

    Thank you for your dissertation on resveratrol for dogs (and humans) which reduces the attention that resveratrol has garnered to “Frenzy” and “hype” I guess the more than 3,000 clinical trials demonstrating its therapeutic potential on the National Institute of Health’s (search box: resveratrol)were all for naught and people should abandon the idea of using it altogether until the ‘drug’ SRT501 is introduced and according to you is worthy of the hype its gotten.

    To begin with, the reason that SRT501 is being developed is that researchers at Harvard Medical School saw how beneficial the natural plant form of resveratrol was on small animals in warding off virtually all the age related diseases including cancer, diabetes and Alzheimer’s disease so they are attempting to synthesize a resveratrol molecule fashioned after the natural one only 1,000 times stronger to be used for therapeutic purposes.

    This way they can get a patent on the ‘drug’ and if it works get huge royalties from it. The only hitch is that it is several years off, if ever, and the natural plant version that has shown this promise is available today. And at 1,000 times the strength and chemical composition, there will surely be side effects.

    I know the difference between a compound showing efficacy in preventive versus therapeutic treatment, however, as you point out above and then minimize, resveratrol has been shown to decrease the spread of colon cancer in mice. If it works in mice and in the colon, do you think it might work in other small animals and on other organs? The National Cancer Institute does. Are you willing to wait 20 years until someone tells you it works on dogs or will the other small animal studies suffice for the time being. Maybe you might suggest we freeze our dogs and bring them back after we have a few more animal studies than the hundreds out there today.

    And your theory about resveratrol being rendered ineffective once it has entered the system because it is destroyed by enzymes is incorrect. Resveratrol is well absorbed and when combined in a lipid base as is the case with Resvantage Canine, post injestion, it combines with bile salts and is absorbed through the unstirred water layer that lines the intestinal tract.

    It is then collected in the liver and not “de-activated” but converted to resveratrol metabolites and released into the system as needed over several hours.

    And there have been studies of resveratrol on absorption or bioavailability specificly using dogs and that study can be accessed from the National Institute of Health’s Public Access. University of Michigan Medical School.

    You also wish to see safety data. Resveratrol is extremely safe and there have never been any instances of toxicity or side effects from mega-dosing both humans and animals with as much as 5 grams over a period of several weeks. The human study was performed in Finland and the animal studies are multitudinous. These are all available to anyone doing more than slap dash research.

    Dr. Robert Sclafani, a cancer researcher and the Chair of the Biochemistry and Molecular Biology Department at CU Denver, has studied resveratrol and cancer and states (1) resveratrol is well tolerated (2) It has extended the life of every living organism it’s been fed to (3) If you feed an animal resveratrol, it’s odds of developing cancer are reduced and (4) resveratrol acts by fooling the cancer cell into thinking its DNA is damaged and it stops replicating.

    Most people are soliciting help, particularly on this site, for treatment for the later stages of cancer. But with many dogs developing cancers, the initiation stage is overlooked because it is not noticable in the animal. The dog is not acting differently and there is no apparent tumor to been seen or felt. At this point, by giving a dog what they think might be resveratrol for preventive reasons, it might actually targeting the cancer cells in the initiation stage and halting them from jump starting a cancerous tumor.

    Early is the time to get at it by administering a natural compound on a daily basis to the animal. With no known side effects with the exception of life extension, it would appear to be a natural for dog owners for both treatment and prevention of cancer.

    • Dr. Dressler on January 31, 2010 at 9:15 am

      Dear Phillip,
      Thank you for your information. I think all the points you have made are worthy of detailed consideration.
      However, I am having some difficulty that I would ask you help with, since I am having a hard time accessing the information that you have for some reason. Maybe you can help us out here?
      For example, you wrote:
      “3,000 clinical trials demonstrating its therapeutic potential”.
      I cannot seem to find them. Can you help me, and more importantly the readers of this blog, by perhaps giving us a link to these clinical trials? Just so the readers are aware, here is an excerpt from Wikedia on examples of what a clinical trial is:

      “Some examples of what a clinical trial may be designed to do:

      * assess the safety and effectiveness of a new medication or device on a specific kind of patient (e.g., patients who have been diagnosed with Alzheimer’s disease)
      * assess the safety and effectiveness of a different dose of a medication than is commonly used (e.g., 10 mg dose instead of 5 mg dose)
      * assess the safety and effectiveness of an already marketed medication or device for a new indication, i.e. a disease for which the drug is not specifically approved
      * assess whether the new medication or device is more effective for the patient’s condition than the already used, standard medication or device (“the gold standard” or “standard therapy”)
      * compare the effectiveness in patients with a specific disease of two or more already approved or common interventions for that disease (e.g., Device A vs. Device B, Therapy A vs. Therapy B)”

      Please provide us with at least some of the clinical trials you mention for resveratrol’s use in cancer treatment.

      Since I know this is a topic that is meaningful, I would like to give more info to this:
      “If it works in mice and in the colon, do you think it might work in other small animals and on other organs?”
      Yes, I do think it might. But it might not because of what I understand, at this point in time, to be limitations with bioavailability, as I referenced with the publication in the blog.

      Again, you seem to have access to data that must be more difficult to find.
      In particular, the information you gave us conflicts with the publication I cited in the blog post:
      “Resveratrol is well absorbed and when combined in a lipid base as is the case with Resvantage Canine, post injestion, it combines with bile salts and is absorbed through the unstirred water layer that lines the intestinal tract.

      It is then collected in the liver and not “de-activated” but converted to resveratrol metabolites and released into the system as needed over several hours.”

      Mr. Caldwell, can you please help us rectify this by providing us with the data? If you are aware of a mechanism which has been shown to do what you say, we would be very interested to see the evidence of this.

      I think the point you made about cancer initiation is a very good one. Unfortunately, the motivating factor for people reading this blog is a cancer diagnosis, far and wide, and thus I focus on this topic more than prevention, at least generally at this point.

      I thank you for your interest in this important topic.

      Dr D

  2. phillip on January 17, 2010 at 7:49 pm

    Doctor D, I’m awaiting an answer concerning my golden retriever.
    God bless Phillip

  3. phillip on January 15, 2010 at 7:09 pm

    Dr. Dressler,

    Months ago, I took my golden retriever in to have a lump in his abdomine
    checked out. My vet told me to keep an eye on it after his examination. He
    thought that the lump was most likely a non cancerous tumor. After a couple
    months went by, I noticed that the growth had got quite a bit bigger, so I took
    my dog in again. My vet tried to use a needle test to try to extract a sample,
    but the growth was so firm, that he could not get the needle to penetrate, so
    he made an incision instead. After viewing the growth from inside, he told me
    that my dog had a growth called fibrosing streatitis myositis. I was then sent
    to a specialist who did a much larger incision to extract some inner samples
    of the growth to be sent out to a lab. The biopsy came back as spindle cell
    sarcoma. A surgury was recommended to remove the tumor, but I was told
    it would be risky because of the tumors size and location. I decided not to have
    the surgury performed. Weeks have passed now, and the tumor is quite huge
    and firm. It fills in both sides of my dogs abdomine, and underneath. His hind
    leg is now suffering from swelling and lameness. Because the tumor is seeking
    more territory, it is now pressing against his organs and stomach, causing total
    lack of appetite, and the ability to hold solids down. My vet recommended a
    half cup of ensure twice a day. I also add some ground up chicken or beef to
    the ensure. I have to totally feed him with a spoon, then holding his mouth some
    what shut se he does not spit the food out. He is also losing weight quite rapid.
    (I forgot to mention something earlier). Please read on. I was told that the tumor
    is now starting to press against my dogs areas, that will soon effect his ability
    to urinate and pass a bowel movement. This is the latest from my conventional vet.
    My dog will not eat on his own anymore, but he is drinking water. I’ve tried Artemisinin,
    cantron, milk thistle, proteo enzymes, IP-6 Inositol, liquid herb detoxifiers, multiple
    vitamins, fish oil, and so on. I considered giving him neoplasene taken orally, but
    was told that neoplasene could cause complications because of the tumors size,
    and possibly leave a hollow hole once the tumor was attacked. The cancer is far
    along, and I’m feeling like my options are running out. I’m considering 2 last options.
    Apicot seeds, B17 along with B15, or Essiac tea capsules, ( Ojibwa herbal blend),
    or something from the cancer fighting strategies site. I would deeply apprieciate
    your opinion on these options, and my general email. I’m also concerned that
    this form of cancer may be so far along at this time, that no magic bullet or
    supplement will work, and that maybe I should just see my vet to give him a
    peaceful exit. Thank you

  4. Ed Leadbetter on January 14, 2010 at 8:19 am

    Hi…. My 11 year old Rough Collie had a peri-anal adenoma which turned out to be malignant back in April 09…He went to have the tumor removed and sad to say they also found shadows on his lungs,so the vet elected not to do it as she was afraid he would not survive the anasthetic….I had read up on Curcumin (part of the spice tumeric)and started him on 6 grams a day and also on resveratrol..That was last April when they said he might last a month or two…It`s now Jan 2010 and went back to the Vet and has had the tumor removed and is doing just fine..The Vet was amazed at his condition.. He goes for short walks eats just fine and goes up and down stairs ok….He also plays tug of war with our 9 month old sable Collie..Right now he is on a lower dosage as a prevent…Ed

  5. Lynne on January 14, 2010 at 6:43 am

    Any news on when Apocaps will be available?

  6. bigdobe on January 14, 2010 at 4:56 am

    My dog was diagnosed with mast cell tumor with metastases. She receives chemotherapy (cytoxan and vinblastine). Our oncologist mutes the side effects with metronidazole (for the bowel), benadryl, Pepcid AC for stomach acid and reglan for nausea. My girl has had no obvious “tummy” problems with this schedule. Incidentally she is also on Hills prescription ID diet. I hope your oncologist can develop a routine which makes your friend more comfortable. bigdobe

  7. Aleeya on January 12, 2010 at 12:12 pm

    Dr Dressler

    My 5 year old Siberian Husky Prince was recently diagnosed with low grade Fibrosarcoma. I got opinions from three vets and he had FNA’s done and then a biopsy. I recently took him out of town to surgical specialists to get a CT scan and was hoping they could excise the tumor. The results were devastating, the tumour is very locally invasive and has envaded and eroded some of his vertibrae and is his spinal cord is already 50% compromised.

    Prince is a stoic, tough dog and is coping very well. He still has full movement of his back legs at this stage which really surprised the specialists. I live in NZ and we don’t have Radiotherapy treatment here for animals, only Chemo which I’ve been told isn’t as effective with this type of tumor. I only really have three options – full chemo treatment, metronomic (low dose) chemo or do nothing. I have opted for the low dose chemo and am hoping for a miracle. The Cyclophosphamide was supposed to be here prior to Christmas but the lab that reformulates it into capsules that are the right dose for Prince, did not get it done in time. He is taking Piroxicam with the chemo drugs and started the Piroxicam before Christmas. The Cyclophosphamide should be here in the next couple of days and I am very nervous and apprehensive about putting these chemicals into Prince’s system but feel I have to try this for him, hoping it may cease further growth of the tumor so his spinal cord will not be affected.

    The Piroxicam is hard on his kidneys and tummy, I am giving him Slippery Elm each day to try & combat his very sensitive tummy (he has damage from prior to when I got him as a pup). His Urea levels are slightly elevated (they were prior to commencing the Piroxicam) and his white blood cell count is slightly low so he will only take the Cyclophosphamide every second day to start with.

    Is there anything else I can give him that will compliment the meds he will be taking and do you think I have made the right decision for him? I realise it’s a long shot but I just felt I couldn’t leave him without treatment as I would have to watch him become paralised, he is too full of energy and too young.

    The last two months have been very stressful and I know the worst is yet to come. I appreciate any help/advice you can give me.

    Thank you
    Aleeya and Prince

  8. Myrl Graham on January 11, 2010 at 8:58 am

    Hi Dr. Dressler…..received your “Dog Cancer Survival Guide” and have jumped right to the diet. My 10 yr old female Bullmastiff recently had a grade 2 mast cell tumor removed – mitotic is 1. My question is this: periodically I go out of town and my husband feeds the dogs “Halo Spot Stew”. This has several ingredients that now I DON’T feed. I’m not sure if feeding Spots Stew for 7 days when out of town would be horrible or what would be a good substitute for when the cooked food runs out. My dogs do NOT eat kibble at all. Thanks for your wonderful book and any suggestions you can give me.

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