Cancer: Not as Hard as We Think

 I'm going to start with a bold claim: cancer has the same cause, and should be treated with the same measures, as obesity.  I didn't say breast cancer, or skin cancer.  Different cancers have different properties that make it useful to study them separately, but all cancers have certain important things in common that make it possible to study cancer as a whole.

Before I go on, let me disclaim myself: I'm not a doctor, and this analysis is not intended as medical advice.  If you have cancer, or want to prevent it, see your doctor, but do so armed with as much information as you can get.

Now that I've made this ludicrous claim, I'd better back it up with some science.  You might first want to cover some cancer basics, which I'm going to skip... possibly here.

I'm going to talk about some things that all cancer cells have in common.  One is called the Warburg Effect after its discoverer.  Warburg described a feature common to all forms of cancer - they carry out all their metabolism anaerobically.  This is important for a number of reasons.  For one, on a low-carbohydrate diet, the only source of fuel available in the bloodstream in any quantity is ketone bodies, which cannot be metabolized without oxygen.  Cancer cells are thus unable to make metabolic use of ketones.  To my knowledge, there's no research available that confirms or refutes this statement, but it's a logical conclusion of the discovery of cancer's exclusively anaerobic metabolism, and should probably be studied closely.

Another, related feature of cancer cells is that insulin receptors are overexpressed.  This means that cancer cells are avid glucose consumers, giving them a competitive advantage over surrounding healthy tissue.  On a low-carb diet, of course, there's hardly any blood glucose to consume, so this critical feature of cancer cells confers no advantage whatsoever, and may well be a distinct disadvantage.  Together with the inability to metabolize other fuels, this means that theoretically cancer cells cannot survive in a human on a low-carb diet.

Possibly the most important feature common to all cancer cells is their ability to avoid apoptosis, or programmed cell death, which in healthy cells is triggered by certain types of damage or DNA transcription errors.  Without this feature, cancer cells would destroy themselves.  There is another process by which cells deal with damage: autophagy.  We don't know as much as we'd like about this process, but we do know that it allows cells to recycle aging and damaged organelles and that it's inhibited by insulin.  This insulin-induced failure of cells to "take out the garbage" via autophagy may, according to many studies (and let me emphasize this one), may be a primary pathway to cancer development.  From the article:

    Malignant transformation is frequently associated with suppression of autophagy. The recent implication of tumor suppressors ... in autophagic pathways indicates a causative role for autophagy deficiencies in cancer formation.

Given this and the fact that "[i]nsulin and its downstream molecules such as mTOR/ S6K1 are well-known inhibitors of autophagy", let it not go without saying that on a low-carb diet, cellular autophagy occurs far more frequently than on a traditional diet, and in theory should reliably prevent the development of cancer according to this model.

There's also considerable epidemiological evidence for the role of dietary carbohydrates in cancer development.  Vilhjalmur Stefansson, a Canadian anthropologist, published a book entitled Cancer: disease of civilization?, where he says:

    "Stanislaw Tanchou .... gave the first formula for predicting cancer risk. It was based on grain consumption and was found to accurately calculate cancer rates in major European cities. The more grain consumed, the greater the rate of cancer."  Tanchou made the claim in 1843, to the Paris Medical Society. He also postulated that cancer would likewise never be found in hunter-gatherer populations. This began a search among the populations of hunter-gatherers known to missionary doctors and explorers. This search continued until WWII when the last wild humans were "civilized" in the Arctic and Australia. No cases of cancer were ever found within these populations, although after they adopted the diet of civilization, it became common.

Modern study of hunter-gatherer populations and their risk of cancer has become difficult because, well, the ones we know about have mostly been destroyed or "civilized" and now consume high-carbohydrate diets.  For a very thorough epidemiological examination of cancer and other "diseases of civilization" among hunter-gatherer populations, check out Good Calories, Bad Calories: Fats, Carbs, and the Controversial Science of Diet by Gary Taubes.  I've linked to this book before, and I will again.  If there's a must-read book for the low-carber or the skeptic, this is currently the one.