Cancer cells

Someone recently asked me how to prevent cancer, so here’s my answer. As the subject of cancer is vast, I’ll keep this brief, and concentrate on what are, in my opinion, the most important things you can do to prevent cancer.

Fight aging

Practically everything I’ve written on this site and in my books applies here. Cancer is far more prevalent among older people, with some 90% of cases in people over the age of 50, and half over the age of 70. See chart below. (Source.) Age is the biggest risk factor for cancer, other than perhaps smoking – but the latter is well known.

Stay lean

Obesity accounts for about 20% of cancer cases. I believe this could underestimate the risks of obesity, since in the Western world cancer rates are much higher than in the undeveloped world, and Western people weigh more. Thus statistics compare obese people to others that also have a relatively high risk of developing cancer. Given what we know about the relation between body mass index and aging and health, I suspect that cancer incidence rises monotonically with BMI. In other words, other things equal, someone with a BMI of 24 has a higher cancer risk than someone of BMI 22.

“Epidemiological studies have found strong direct associations between increasing body mass index (BMI) and risks of developing type 2 diabetes, cardiovascular disease, and several types of cancer, beginning from BMI of 20–21 kg m−2.” (Source.)

However, we know that body fat determines the health risk from BMI, so if you have a higher BMI due to muscle, you’re not likely at any increased risk.

Build muscle

Muscular strength is associated with lower cancer death rates. The reason for this is probably not due to a protective effect of muscle in itself, but because more muscle means better insulin sensitivity and better overall health. You don’t need to be an actual bodybuilder to benefit from this effect of muscle, you just need to keep your muscle in fine tune and to retain muscle as you age. That means you should train for strength.

Watch the carbohydrate and sugar intake

High intake of refined carbohydrates and sugar is associated with cancer, and people living a hunter-gatherer lifestyle without these foods suffer very low cancer rates. The reasons that carbohydrate and sugar consumption promote cancer may be several, such as

  • cancer cells feed on sugar (glucose), so providing it to them promotes it; conversely, depriving them of it may prevent it and/or kill them
  • carbohydrates and sugar lead to high levels of insulin and IGF-1, growth factors that promote cancer
  • sugar promotes iron overload.

Don’t use vegetable oils

Vegetable oils are known to be carcinogenic due to the high amounts of omega-6 fatty acids in them. They’re an industrial product that should not be used. Strive to maintain a balanced omega-6/3 ratio, which necessitates not only trashing your vegetable oils but possibly also supplementing with fish oil.

Keep iron levels in the low normal range

Just as they feed on sugar, cancer cells have an appetite for iron. Iron is a growth factor, and rapidly dividing cancer cells require more of it than normal cells. Below is a chart showing cumulative cancer incidence in a group of patients who reduced iron via phlebotomy, vs those who did not. (Source.)

Anti-cancer supplements/drugs

A number of supplements have been shown to prevent cancer in humans or lab animals. Among them are:

  • aspirin
  • curcumin
  • berberine
  • resveratrol
  • IP6
  • metformin
  • magnesium
  • zinc


Cancer prevention is intimately linked with all the good things you can do for your health. As I see it, maintaining good insulin sensitivity, keeping iron in the low normal range, avoiding garbage food, and the application of hormesis (exercise, supplements) are key factors.

PS: Check out my Supplements Buying Guide for Men.

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  1. Dom says:

    So is Olive oil to be proscribed ?

    • P. D. Mangan says:

      No, olive oil is perfectly healthy and is not an industrial seed oil, but the oil of a fruit. Industrial seed oils (vegetable oils) are those like corn, safflower, soy, canola. Other healthy fats that you can use freely include coconut oil, butter, lard, ghee, tallow.

      • Master Bonafide says:

        Apparently High Oleic Seed oils are modified to be more like the structure of Olive oil (via David Gillespie), I personally still avoid them (they come with high carbbie things anyway) but it is worth noting.

  2. Dom says:

    Thank you for the answer ! i have always loved olive oil, so it is a relief. My father used to drink a little of it to calm the sting of raw garlic !!!
    And sunflower oil ? seems like a nutirent poor industrial seed oil to me…Yet it’s a staple oil in Europe

  3. Dom says:

    repost with correction
    Thank you for the answer ! I have always loved olive oil, so it is a relief. My father used to drink a little of it to calm the sting of raw garlic !
    And sunflower oil ? It seems like a nutrient-poor industrial seed oil to me…Yet it’s a staple oil in Europe.

  4. Craig says:

    A friend of mine had pancreatic cancer. They told her to restrict both sugar and meat because both fed the cancer.

    Anecdotally, all the big meat eaters I have known developed cancer and or heart disease including all the members of my family except for me. One of the advantages of living to your mid 60s is that life has become a longitudinal experiment in which you see the results of a particular lifestyle.

  5. Nick says:


    Any reason you didn’t recommend sulforaphane (broccoli sprouts etc) here? I’m perusing your latest book, and I notice you didn’t mention it there either, presumably because you’re hitting NRF2 with curcumin etc. Sulforaphane seems to hit a few pathways though, notably targeting cancer stem cells.


    • P. D. Mangan says:

      Hi Nick – The other supplements that I mentioned do activate Nrf2, but also, as far as I can see, seem to be where more interest on the part of researchers and clinicians lies. I looked into sulforaphane years ago, but don’t seem to come across it much anymore. But, it is anti-cancer, and I could be wrong about the degree of interest in it.

      • Nick Westgate says:

        Well, nobody is making money off it, so yeah, not as much research as there should be. ; – ) Rhonda Patrick has posted a video with a good summary of some of the more interesting findings … Also note it’s a myostatin inhibitor, and from a Japanese study this year causes “amelioration of obesity through enhancing energy consumption by browning of adipocytes, and reduction of metabolic endotoxemia through improving gut bacterial flora”. So yeah, certainly deserving of more attention!

      • Ole says:

        Cancer can mutate and exploit the Nrf2 pathway thereby making Nrf2 targeted supplements useless. This is espcially true for pancreatic cancer, which is resistant to chemo and radiationtherapy.

  6. Steve says:

    Selenium is certainly missing here.

  7. Thinker says:

    Here is a recent (2017) paper investigating how curcumin induces autophagy and apoptosis in very dangerous prostate tumor cells.


    Curcumin induces apoptosis and autophagy in different cancer cells. Moreover, chemical and biological experiments have evidenced that curcumin is a biologically active iron chelator and induces cytotoxicity through iron chelation. We thus hypothesized that curcumin may induce apoptosis and autophagy in castration-resistant prostate cancer (CRPC) cells through its iron-chelating properties.

  8. Nick says:

    The other Nick here… Do you explain how sugar promotes iron overload somewhere?

  9. eah says:

    Hello Dennis, and again many thanks for your work — I don’t want to be a pain, but … I would like to buy all of your books, but not necessarily at AMZN — is there an alternative?

    Also, re oils: I generally use Leinöl (linseed oil) due to its high omega-3 content — eg when making vinaigrette for salads: approx 60% olive oil, 20% Rapsöl (rapeseed), 20% linseed oil (it has a strong taste, so you have to be careful about using too much of it), with some mustard and vinegar — I also use vinaigrette as a source of fat on vegetables and rice.

    • P. D. Mangan says:

      Hi eah – unfortunately, Amazon is the only place, other than CreateSpace, which is an Amazon subsidiary. If you like, you can contact me (via contact form) and I can supply you with books in PDF format.

  10. Rob H says:

    Hi Dennis, I bought your book this week and just wanted to let you know how much I’m enjoying reading it – very thought provoking. Although you have mentioned some of the points in your blog posts before, seeing them expanded upon and presented in that way has really given me some new insights, particularly with helping out my mother who I think I mentioned in a previous comment is suffering from metastatic cancer (originally breast cancer which spread to the bones 3 years ago – she also has osteoporosis). I have been following your recommendations and pretty unbelievably the cancer has remained fairly static over the last few years – 5 years ago the doc gave her a 3 year prognosis, so I just wanted to let you know that your advice really is helping prolong lives. I did have a question for you though: very recently my mother has become quite frail and lethargic and often has to spend the whole morning in bed, plus she has also developed problems with her short-term memory over the last couple of years (she is 78 years old by the way). In addition to the 2 weeks on/ 2 weeks off Capecitabine chemotherapy tablets, I have been getting her to take the following supplements each day: Morning: 4,000 IU Vitamin D3, 1500mg Glucosamine, 4,000mg Garlic Oil, 3mg of Boron, 100mg of Grapseed Extract, 400mg of Berberine HCI, 100mg of Co-enzyme Q-10, 15mg of Zinc Citrate, 280mg of salvestrols (superior to resveratrol apparently), 1 x 3 billion Acidophilus probiotic capsule, 1 teaspoon of regular cod liver oil and 1 x baby aspirin. Phew! She also takes an additional salvestrol capsule at night, together with another probiotic capsule and a turmeric capsule. First thing I am going to change after reading your book is switching out the turmeric capsule for a curcumin capsule instead which should be more potent.

    Sorry this is so drawn out – but my question to you is a.) what do you think of this supplementary regime and b.) I have been in a real quandary about whether to start giving her a whey protein shake each day, to help fight her cachexia and also to help with her serotonin (she finds it difficult to sleep and has a pretty low mood most of the time)? But I’m not sure if the whey would promote her cancer to grow/ metastatsise faster? It’s just that at the moment she seems to really be losing her vitality quite quickly and I feel like I need to do something. Maybe BCAAs, as I know Thomas Seyfried and Dom D’Agostino use this in their metabolic treatment of cancer (my understanding is that they do not use whey as they believe that the Glutamine it contains can be used as a fuel for cancer – similar to glucose). I know you are not qualified to give medical advice, but if it were your mother, what do you think you would do? Many thanks for any light you can shed on this for me!

    • P. D. Mangan says:

      Hi Rob, thanks for buying the book and for the nice feedback. I do recall that you mentioned your mother previously, and she obviously has a devoted son in you. However, I’m sorry to say that I think I’d better stay away from advising you about her supplements, much as I would like to help, as it’s just too close to trying to give medical advice. Maybe you could seek out a dietitian who’s versed in this sort of thing; I realize that may be difficult, since they all seem to advise carbs and more carbs, but there are some around. Franziska Spritzler springs to mind, she’s at Low-Carb Dietitian, although it might be nice to find someone to consult with in person. Whether she or anyone else could advise you on supplements I don’t know.

      • Rob H says:

        OK no problem Dennis, I can understand your position on that – many thanks for the heads up with a Low Carb dietitian – sounds just up our street (you are dead right – when my Mum took a turn for the worst 2 years ago and lost her appetite – which thankfully she recovered from – she was prescribed cans of Ensure – which I quickly got her off thank goodness! I think I have made my mind up though to start her on some whey protein each day in the meantime since I have noticed that she is not eating very much protein and her vitality is really slipping away at the moment – she spent another morning in bed today and her shirt term memory is declining fast . At the end of the day I have to admit it is health-span rather than lifespan that should be the main goal here.. I’ll let you know how it goes – thanks again!

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