Dear Mark: Does Chicken Cause Cancer, Should You Neuter, Dog Collagen, and Skipping Dinner

For today’s edition of Dear Mark, I’m answering a few questions. First came in from an email and regards a new study showing a link between chicken eating and several types of cancers (melanoma, prostate cancer, non-Hodgkin’s lymphoma) among British adults. What do I think of the study? Second, did I really tell people not to neuter or spay their dogs? Third, can dogs take collagen powder, and if not, are there any alternatives? And last, I address a comment about early time restricted feeding.

Let’s go:

Hey Mark,

What are your thoughts on this study that showed a link between chicken consumption and cancer?

Okay, let’s do this.

First of all, the link wasn’t between chicken and cancer, it was between chicken and specific cancers. The specificity suggests that there may be something going on here.

Look, I love a good roasted chicken. There’s almost nothing quite like crispy chicken skin.

But today’s birds are exceedingly high in omega-6 fatty acids. Your standard battery-fed bird—which is what most people in these studies are eating—eats a diet of soybean oil, corn byproducts, and other junk high in omega-6 fats. Those dietary fats are incorporated into the animal’s tissues, which get incorporated into your dinner, which get incorporated into your body.

Most of the cancers in question have been previously and mechanistically linked to elevated omega-6 levels and/or reduced omega-3 levels.

Melanoma and other skin cancers?

One study out of Australia—land of skin cancer—found that adults with the highest serum concentrations of DHA and EPA had the least “cutaneous p53 expression.” When your skin is in danger of damage from the sun, p53 expression is upregulated to protect it. The fact that p53 expression was low suggests that the skin wasn’t in danger; the omega-3s were protecting the skin and reducing the “perceived” (and real) danger. Acute intakes of EPA reduce the inflammatory skin response to UV radiation.

One problem of excess omega-6 fats is that they crowd out DHA and EPA from the serum and cellular membranes. The more omega-6 in your diet, the less DHA and EPA you’ll have laying around to protect you from the sun.

Prostate cancer?

Anti-inflammatory omega-3 fatty acids (found in seafood and fish oil) are generally linked to lower rates of prostatic inflammation and a less carcinogenic environment; omega-6 fatty acids can trigger disease progression. A 2001 study of over 6,000 Swedish men found that the folks eating the most fish had drastically lower rates of prostate cancer than those eating the least. Another study from New Zealand found that men with the highest DHA (an omega-3 found in fish) markers slashed their prostate cancer risk by 38% compared to the men with the lowest DHA levels.

I didn’t see any solid evidence one way or the other with non-Hodgkin’s lymphoma, but omega-3 intake is linked to a lower risk. If that’s a causative connection, and excessive omega-6 is competing with your omega-3s for physiological supremacy in the body, that could increase the risk of non-Hodgkin’s lymphoma. But again, this isn’t a sure thing.

I couldn’t find the study mentioned in the article, but according to the article the scientists focused only on “meat consumption patterns.” They weren’t looking at other foods or nutrients—just what kind of meat they ate. If that’s the case, they wouldn’t have controlled for the intakes of fries and mayo and other junk foods often consumed alongside chicken.

British are eating more chicken than ever before, and they’re moving increasingly away from big family chicken meals—roasts and such—toward individual chicken meals for one—pasta and stir fries.

The fastest growing fast food in Britain is fried chicken. That’s chicken that’s been breaded in flour and fried in reused, rancid vegetable oil, then served alongside french fries and smothered in mayonnaise.

Now, I’m not going to say you should eat chicken for every meal. Red meat, fish, and eggs offer far more nutrients than chicken, and they’re much lower in omega-6 fatty acids. But I’m not going to shy away from a good roast chicken, or even a chicken chili, especially if I’m using well-raised, preferably pasture-raised chickens.

I’m sorry, are you recommending people DON”T spay/neuter their pets?!? Am I reading an article in The Onion? Is it April 1st? What the hell is going on??? Dear Bob Barker is rolling in his grave and thousands of dogs and cats will be unnecessarily euthanized today (and tomorrow, and the next day, and the next….) because there are just too many of them.

Nope, I’m just recommending that people read the literature and understand that spaying/neutering can have unwanted health effects, especially if you do it too early.

Most experts agree that fixing the dog after they’ve stopped growing is pretty safe and reduces the risk of later health issues. That to me is a good compromise.

And I’m not speaking to the masses. I’m speaking to the people reading this who are in general a reliable, conscientious bunch.

Also, a vasectomy is a good option that few people consider but more vets are offering.

Mark, would there be any harm or benefit in throwing in a scoop of collagen on top of my dog’s raw meat&veggie patty?

You could definitely do it. Just be aware that I’ve found some dogs have bad digestive responses to protein powders of any kind. A raw chicken foot will do the trick, if you’re up to trying it. I’ve also seen freeze-dried tendons in pet stores.

After a few years of IDF that had me mostly eating between noon and 8, I recently tried early time-restricted feeding (eTRF) and man it seems to work well for me. I did it under the influence of this guy’s posts:

And I learned about him from an MDA post…


Two things.

Yes, some people for whom intermittent fasting doesn’t seem to be working may want to switch to an early feeding system. The vast majority of people who skip meals every day are skipping breakfast. It’s easier that way, you can just have some coffee and keep trucking. But not everyone benefits from it. If that’s you, try eating breakfast (and lunch) and skipping dinner.

And yes, Bill Lagakos is a great resource. Always love his stuff, even or especially if it conflicts with something I held to be true.

Thanks for reading, everyone. If you have any more questions, drop them down below!

About the Author

Mark Sisson is the founder of Mark’s Daily Apple, godfather to the Primal food and lifestyle movement, and the New York Times bestselling author of The Keto Reset Diet. His latest book is Keto for Life, where he discusses how he combines the keto diet with a Primal lifestyle for optimal health and longevity. Mark is the author of numerous other books as well, including The Primal Blueprint, which was credited with turbocharging the growth of the primal/paleo movement back in 2009. After spending three decades researching and educating folks on why food is the key component to achieving and maintaining optimal wellness, Mark launched Primal Kitchen, a real-food company that creates Primal/paleo, keto, and Whole30-friendly kitchen staples.

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20 thoughts on “Dear Mark: Does Chicken Cause Cancer, Should You Neuter, Dog Collagen, and Skipping Dinner”

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  1. I use Non-Hodgkins Lymphoma as a proxy to track how well we’re doing at treating autoimmune illness, and vague flu like fatigue syndromes. It came to my attention after I noticed that almost all AI diseases also say something about “… and later on you have a higher risk of NHL.” Even the vague, untreatable ones or rare ones will say that. I’m guessing that Zinc status would have a larger effect on NHL than omega-3, but I haven’t seen studies showing it. They may exist, I just haven’t seen it.

  2. A vasectomy will not reduce the likelihood of any of the health problems associated with neutering, nor will it reduce any of the behavior problems associated with testosterone that send dog owners running for the surgical solution. All it will do is prevent the dog from fathering pups.

    Perhaps you meant a vasectomy would remove the risk of unwanted litters while allowing the dog to reach full growth before neutering?

    1. that is not true. Vasectomies WILL reduce problems associated with neutering in males: joint and cartilage problems, some cancers, prostate cancer (which has a higher incidence in neutered dogs, surprisingly).

      however what it will not do (and which is NOT a problem in neutered dogs), is prevent prostatitis.
      to prevent prostatitis, simply neuter your dog around the age of 5-8, depending on breed, and that will prevent prostatitis in most dogs, whether it is vasectomized or not.

      vasectomies also will not prevent territoriality, roaming, and increased motivation-(sometimes shows up as increased aggression) in male dogs. however those behaviors sometimes show up anyway in males, or even females whether neutered or not.
      if one is a good dog trainer, these problems can easily be channeled and controlled, if an intact or vasectomized dog is desired. however, as a veterinarian, i do recommend neutering most male dogs at around 10 months-1 year for most people, as they simply aren’t going to train their dogs adequately. Better an easier neutered dog, than another dog in the pound, i say!
      IMO, for those who just want an easier dog in the city, neutering IS recommended.

  3. All bones are saved for stock and the (large breed senior) dog gets it daily. Approximately half a cup every morning. He is holding up well despite being a ball chasing addict on hard ground.

    Speaking of early castration, we were told by his previous owner that he arrived at a refuge at 6 weeks of age. No doubt he was done young. His really long legs hint at that.

  4. If you cannot secure your bitches while they are on heat, you probably shouldn’t own dogs. If you cannot restrain your dog from wandering to the neighbour’s bitch, you probably shouldn’t own dogs.

    No… I’m not speaking from theory, I own over a dozen.

    What you want to do for your own convenience is up to you, but it IS about convenience. Dogs must be restrained at various tones for their own safety.

    1. Can’t agree enough. Owning a dog is a big responsibility, and if a person can’t keep their dog under control at all times, they shouldn’t own one. The reason for all the unwanted litters, dog bites, dog fights, etc, boils down to one thing- irresponsible owners who don’t discipline, properly train, or otherwise look after their dog(s). I’ve always had unaltered dogs and have never had any unwanted litters. Proper training and socialization is a must as well. Some people may feel better in altering their dog, and that’s fine, but it’s certainly possible to have an unaltered dog that never breeds and is a well behaved and happy animal.

  5. Thanks for the roundup of great questions Mark, and Bill’s blog looks very interesting, appreciate the link.

    I’ve just started the carnivore diet for Crohn’s disease and am finding my inflammation is really down and my digestion is great! What are your thoughts on why this is working and has worked for so many IBD/IBS sufferers?

    Also what would you add in terms of supplements to help keep healthy when doing carnivore? At the moment I’m eating grass fed meats, fish and seafood plus supplanting with kombucha and aloe Vera for digestion. Any tips or advice from your perspective would be great.

    Cheers Thomas

    1. As an IBS sufferer I would like an update on the carnivore diet to! Have seen so many people claiming to have improved their symptoms I’m very tempted to give it a try.

  6. People who haven’t taken the time to read your post directly should not waste your time questioning there content. You posts are way too thorough for anyone to misunderstand.

  7. I had a labrador mix that developed major hip dysphasia and lots of neurological problems. He was spayed as a puppy via the dog rescue agency I adopted him from. Interesting correlation.

  8. True pasture raised chicken can be 3-5 times higher in Omega 3 than conventional chicken. However – user beware! Labels like “Free Range”, “Organic” and even “Pasture Raised” are 99% of the time marketing gimmicks! Find a real farm that you can trust if you want chicken with an appropriate 3-6 ratio.

    1. Farmer Paul-
      Have you guys tested your (amazing looking) birds for their Omega 3:6 ratio? And then compared it to store bought ”free range” chicken??
      That would be super interesting if a large enough number (20 or so??)!

  9. Mark : I would like to buy an electric foil. What brand did you buy. What was your leading curve?

  10. Always love your Dear Mark posts, always very insightful thank you Mark,

    I’m interested to know your thoughts on ‘European golden pea’ protein powder. It’s marketed as vegan, paleo and low allergy. It has very few carbs and supposedly all the amino acids just by itself? What are your thoughts? A good option for a dairy free protein powder?

    Cheers Nathan

  11. The original study was an abstract of an oral presentation in a congress.
    Society for Social Medicine and Population Health and International Epidemiology Association European Congress Annual Scientific Meeting 2019, Hosted by the Society for Social Medicine & Population Health and International Epidemiology Association (IEA), School of Public Health, University College Cork, Cork, Ireland, 4–6 September 2019

  12. When I saw “dog collagen” I had a quick thought about collagen from dogs.