Cancer in Dogs: Causes & How to Prevent it

02nd August 2022

Guest Blog: Dr Conor Brady

Cancer in dogs is on the rise, but why? Here Dr Conor Brady gives you a wealth of information on the causes and preventions too. A must read!

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Dogs, the Most Cancer-Stricken Animals on the Planet

With all the chemical and plastic junk we have injected into our environment and food chain, it's little wonder humans are now one of the most cancer stricken animals on the planet. We are in fact in second place, juuusssstt behind dogs...and by “just” I mean they've lapped us TEN TIMES.

Yes, somewhat unbelievably, as good as we try to be for them – the best of kibble and veterinary care, monthly parasite prevention, annual boosters, all the things we are told to do to preserve their health – these incredibly weak creatures still manage to be approximately ten times more likely to get cancer than us humans. Isn't that staggering? 5,300/100,000 pampered pooches in America each year are diagnosed with cancer compared to just 500/100,000 Americans.

Now to make that a touch worse, we now know that 90-95% of cancer today is not genetic, it is driven by environmental and lifestyle factors. As the saying goes, genes may load the gun but environment pulls the trigger. For example, you can be prone to lung cancer but if you don't smoke you are more likely to get away with it.

In short, it's us that's doing it to them. Something we are putting on or in (or around) our dogs is tripping the cancer switches.

High Carb Diets Are to Blame For the Majority of Cancer We See in Dry-Fed Dogs Today

Diet plays a very significant role in the development of cancer, with poor quality fats (kibble), ultra-processed meat (kibble) and too much salt (kibble) among the chief protagonists but no one food group affects us more than and too much refined carbohydrates (kibble, kibble kibble).

To get a better understanding as to why (and why they need to be avoided in the dog with cancer), I've given you below an excerpt from my book Feeding Dog (*Please note: for the scientists among you, I have removed all but the last references I used in order to make the passage easier to read):

“Tumours are total carb / sugar junkies. In fairness, all cells need sugar to operate but cancer cells use glucose at 10-20 times the rate of normal cells. Their high sugar-uptake is actually the main way we look for them, using a method called a PET-CT (Positron Emission Tomography and Computed Tomography) scan. PET scans use radioactively labelled glucose to detect sugar-hungry tumour cells. When patients drink the sugar water, the mix gets preferentially taken up by the cancer cells and they light up. This helps physicians see where it is, to evaluate the extent of the disease, to deduce which treatments to use and to check if those treatments are working. In fact, all the way back in 1931 Otto Warburg won the Nobel Prize for his discovery that cancer cells have a different energy metabolism to healthy cells, notably a greater rate of glycolysis (the process of converting glucose to energy) compared with normal cells.

In this way, a high sugar diet and cancer are the best of friends, but the relationship goes much deeper than that. Macrophage-mediated programmed cell removal (PrCR), or phagocytosis for short, plays an essential role in tumour surveillance and elimination. These are the seek, engulf and destroy cells of the immune system. We’ve known since 1971 that just 100g of sugar via sucrose, honey or orange juice significantly reduces phagocytosis in humans and the effect can last up to five hours. If you’re a cancer cell thinking of getting up to mischief, this is most welcome.

It gets worse. As more and more sugar is consumed, cell-resistance to insulin builds, meaning more and more insulin is released into the blood. Insulin is a powerful stimulant of cell growth as it drives fuel into the cell. Cancer cells have 10-20 times the insulin receptors of normal cells which enables them to gorge on glucose. In this way, excess sugar leading to obesity and high blood insulin is an important factor in cancer.

These insulin receptors are everywhere in your body. Hence too much sugar, coupled with excess insulin, is now firmly linked to the development of cancer of the breast, ovaries, pancreas, biliary tract, lung, gallbladder, stomach and colorectal cancer of humans.

Tavani et al. (2006) studied 2,569 women with breast cancer and 2,588 females without. They found a direct association between breast cancer risk and sugar consumption, a result of an increase in insulin and insulin growth factors. Unsurprisingly, the advice for humans with mammary tumours is to reduce the carbohydrate / sugar content of your diet.

It happens that mammary tumours are the most frequently diagnosed neoplasm in intact female dogs. What’s more, dogs are known to suffer mammary cancer at least 2 to 3 times the rate of humans. The incidence of breast cancer in human females is currently around 12% worldwide. On their website in 2017, the American College of Veterinary Surgeons states the that the risk of a female dog developing a mammary tumour is “0.5% if bitches are spayed before their first heat (approximately 6 months of age), 8% after their first heat, and 26% after their second heat”. That’s 1 in 4 intact adult female dogs (the ACVS go on to state that while 50% of mammary tumours are benign and 50% are malignant though thankfully few of the malignant mammary tumours are fatal).

As we know mammary gland tumours share common features between dogs and humans, with authors noting dogs make excellent models for the development, prognosis and treatment of breast cancer in humans, does it not follow that a high carbohydrate diet and permanently high blood insulin will plays a significant role in this the most common cancer of dogs?!

I’ll save you the suspense - we have known for more than 20 years that reducing carbohydrates in the diet prevents tumour growth in dogs. The author notes that dogs with cancer are proven to do significantly better on diets containing less carbohydrates.”

My Dog Has Cancer, What Do I Do?

It surely goes without saying that cancer is complicated. You can be on the best diet, which surely increases your chances, but you can still get unlucky. The reason being there are a number of horrible products and lifestyle choices out there that can fuel such a diagnosis. Below I deal with the top five.


Go keto - feed a fresh diet higher in fat, moderate protein and virtually zero carbs.

For those confused as to how much of which think fatty beef mince in the shops which is slightly more fat than protein (say 25% fat, 20% protein, the rest being water). When we look at this via metabolisable energy (ME) lens, important for keto, we fat offers around 2.5times the energy than protein, equating to a ME ratio of nearly 3:1. This is where you want to be for keto.

Recommended meat ingredients

We still work with the rough 70:10:10:10 ratio (meaning lots of meat, 10% bone, 10% organ, some plant matter for their bioactive compounds) but your mixes should now be made with higher fat red meats such as beef, pork, duck, oily fish, maybe lamb depending on the pieces used (chicken and turkey don't have the oomf and you'll be running around looking for fat additions). Mussels and eggs are great additions here too.

It's important that your meats are now as good as possible. This means outdoor reared, organic, all that stuff. Studies show intensively reared meat, particularly chicken, is inflammatory to dogs, albeit this is a US study, a mix of the antibiotics used, that reside in the bones of the bird and the high omega 6 content of the meat from the grain diet.

Organic, outdoor-reared meat contains much more omega 3 so using such meat means we have to think less about the omega 3:6 ratio which, with a cancer diagnosis is important. We now aim to fight inflammation by keeping the amount of omega 3 up (and 6 down) in our diet. Omega 6 comes from veg oils so we now avoid these in cancer dogs. If you had to use one though (say to increase the fat content of a lean meal) something like coconut oil is fine, lower in omega 6 and full of MCT (medium chain triglycerides) which the body loves.

Common question 1 – should dogs with cancer eat raw dog food? First off, if your dog is going through chemo and you're heavily stressed, don't give this a seconds thought. Feed him lightly cooked food. But as soon as that dog comes home, contrary to what you hear on many vet websites (that also claim you shouldn't feed fresh food to healthy cats and dogs...), the answer is almost certainly yes to fresh food. All human patients living with cancer need fresh food, it's part of their recovery. Good quality raw dog food is one of the cleanest, most nutrient dense substrates you can now feed your pet....particularly when for comparison we have kibble – a product beset with microbiological contamination, recalled regularly for not only Salmonella but also containing cancer-causing nasties such as mycotoxins and this is before we talk about its other cancer-causing issues such as ultra-processed protein, poor quality fats, high salt content, conical flask nutrients, lack of bioactive compounds, myriad of chemicals, anti-life which napalms the gut flora, the fact it's bad for teeth which spikes inflammation. Above all, multiple studies now prove it is highly inflammatory to dogs.

There are no perfect options here guys. You can only do your best and the best is real food. Don't let them sell you otherwise.

Common question 2 – how much and how often should you feed a dog with cancer?

The answer is really whatever he needs. As this is a higher fat diet, he will not need as much, say around 2% of his body weight per day and adjust from there. If he is guts are not in good order (or he is losing weight), he will need more.

How often is important. We now know we are eating too much and too often. It takes an enormous amount of energy to process a meal. That's why you feel tired and yawn after large meals. It takes 16hrs to process that meal – 8hrs to digest and assimilate it and another 8hrs to pack it all away. The noble prize was awarded recently to scientists that showed after 16hrs of not eating your body goes into autophagy (something like housekeeping). No longer distracted with digestion, it begins to zap cancer cells. This is why we advise dogs with cancer get 1 or 2 meals and those two meals shouldn't be more than 6hrs apart. This is termed intermittent fasting. More on that here.

Recommended Plant Ingredients

The veg I recommend are chosen for their cancer-fighting properties. They include spinach and kale (folate), broccoli sprouts (get used to growing your own, broccoli sprouts contain all sorts but they are particularly high in cancer-fighting sulfrofane, 100-400 times as much as normal cruciferous veg!), tomato puree (lycopene, cooked tomato has more than raw!), celery (luteolin), zucchini (manganese). I steam there to make them easier to digest. Give the water they're cooked in too (contains any good bits that fell out!).

While we urge you to avoid fruit for now (sugar) wild berries are simply too important to ignore and, thankfully, are low in sugar. Check out Loov online – wild bilberry and sea buckthorn, shaken from trees in the forest. Deeply nutritious and full of polyphenols and anthocyanins, potent antioxidants and proven highly anti-cancerous in studies). Just a dusting, very beneficial.

Paleo Plus Berry Good is Supplement containing Wild Berries.

Food Items to Avoid

You must remove all sources of sugar including rice, potatoes, pasta, starch-rich veg such as peas, carrots and potatoes and fruit. Feed them like a carnivore to starve tumour growth.

No more packet food or treats. We need to avoid all chemical preservatives. Make your own meat-based treats!


  • Vitamin E is needed now to balance out the higher fat diet. Recommend 500IU for small dogs, 1000IU for medium dogs, 1500IU for large dogs
  • Omega 3 from marine source if not feeding oily fish regularly (I recommend sardine oil or phytoplankton such as Norsan, great bang for your buck in terms of EPA/DHA, the omega 3's you need now). They need 200mg EPA & DHA /kg/day
  • Seaweed is stuffed full of anti cancer compounds. More more please check out Kelp For Cancer. We have taken 4 of the seaweeds mentioned below and put them in Ac4. We recommend 1-2g AC4 per 10kg of dog per day.
  • Probiotics are important after your dog receives a conventional treatment (eg chemo or antibiotics). The gut is the main source of inflammation in the body. We must keep the gut flora happy and well balanced. We do that by feeding them correctly (check) and, now and again, sending in some recruits when they take a battering.
  • Golden Turmeric Paste is one of the most famous natural anti-inflammatories out there. It has a long history of fighting cancer. Studies show it can contribute to the death of cancerous cells, reduce angiogenesis (growth of new blood vessels in tumours) and reduce metastasis (spread of cancer). We recommend 1/3 of a tsp per 10kg of dog per day. Careful with GTP, there is a drug clash here with blood thinners and some anti-inflammatories from your vet.
  • Astaxanthin is incredible. A pretty pricey little red algae, in vivo and vitro (in lab and real life) studies abound that it is anti-tumour. Your dog will need 1mg per 10kg of dog per day)
  • Mushrooms are another incredible item to take advantage of right now. Turkey tail and lions mane are some of the most famous. I would just pick up an anti-cancer mushroom mix from a company that specialises in that sort of thing (1/2 tsp per 10kg of dog per day, more initially)

Remove all Unnecessary Chemicals From Their Life

There has never been a better time to go natural. You need to reconsider your use of everything. First to go are all the chemical flea and worm treatments and unecessary boosters. We don't have time to get into it now but suffice to say your dog has bigger problems right now than the parasites he doesn't have! And they say rather the parasites than the chemicals used to prevent them. We don't dose our kids with these things and you needn't use them on your dog, necessarily. Please read up on the natural approach to the aforementioned “threats”:.

  • Natural Flea Treatment for Dogs
  • Cure Worms in Dogs Naturally
  • Dog Vaccinations

You also need to get rid of those poisonous lawn chemicals. Studies show our little sniffers are particularly susceptible to them on a cancer-front.

Next turn your attention to inside your house. Plug in air fresheners, sprays, scented candles, all of them can be a problem. What are you cleaning your floor in? Still using chemical anti-life?! That has to go. Now's the time to jump to probiotic floor cleaners. Now, instead of trying to kill the baddies (which only lasts while the product is wet, once dry it blows away) you layer good guys on your surfaces which sit there and outcompete the bad guys. Isn't that amazing? You can use them on your floors, surfaces, bathrooms, everywhere. Even hospitals are now taking this approach. Check out the results from this Italian hospital. Truly incredible. I recommend Ingenious Probiotics in the UK for a list of these sorts of info and products. Great company.

Other Bits

  • Good water: Stop with the chlorinated tap water! Ever wonder why your dog likes drinking out of mucky puddles?! We are really guarding that gut flora now so filtered water ideally, boiled-then-cooled if you don't have one. You can try offer them some fancy waters now and again too, that is a bowl of water with a little good quality salt dissolved in (electrolytes) or a teaspoon of spirulina etc. See which one he selects. They know what they need (called Zoo Pharmacognosy, find it online, very interesting!). And no more plastic bowls!!!!
  • Get them lean (but don't starve!): Every gram of body fat is inflammatory. When you remove the carbs much of the carb-pudge should fall away but please focus here. Weigh him or measure his waist (behind his last rib) every week or so. Hold yourself account. Very lean. These animals (most, but not all!) are long distance running animals. Think Mo Farrah. Studies of humans show lean is most important for longevity.
  • Clean those teeth: Dirty teeth is highly inflammatory, a constant draw on resources. Animals with tartar and gum disease are shown to suffer more disease. Raw meaty bones clean teeth best, that's a fact. If the tumour is in his mouth and he can't chew, I recommend our product Canident for cleaning teeth. Its highly effective (but can't be used WITH AC4. Stop the latter until the teeth are clean, Canident will do a little of what AC4 does in the mean time).
  • Keto flu: When you see runners “hitting the wall”, this is them going into keto, that is, switching from burning carbs to fat. It can be unpleasant. Sometimes, a previously high-carb fed dog might appear a little down in the dumps for the first day or two. As long as his poops are OK, bear with it, wait till you see him in a few days!

That'll do start guys. Most of the above can be done in conjunction with a move conventional approach. In fact, concepts like great food are essential to their recovery. Please discuss any and all concerns and feeding regimes with your vet (ideally one that has studies nutrition – the ones not recommending high carbohydrate dry food for your pet...). Please visit the RFVS website for a list of vets that can help you in that regard, many are but a Zoom consult away.

Further Reading

23rd May 2024

Guest Blog: Anna Webb

It’s interesting that there are many flea ‘species’, including dog fleas, hedgehog fleas, human fleas, but 90% of the world’s flea population is the very well adapted ‘cat flea’ otherwise known as 'Ctenocephalides Felix’.

Read more