Can we prevent even more than 40% of cancer deaths?

Last week’s blog post summarising a recently-published article which calculated that 40% of cancer deaths in Australia could have been prevented with simple lifestyle changes prompted some readers to ask the question,

“Only 40% of deaths? Aren’t even more cases of cancer linked with diet and lifestyle?”

The answer to that question is almost certainly “YES!!!!” However, for the sake of credibility, the research team which came up with that 40% figure only selected lifestyle exposures which are declared to be known causes of cancer by international research bodies such as the World Health Organization, on the basis of solid and consistent scientific evidence in humans (not lab rats).

It took decades of research and over 800 studies to convince the 22 experts on the international advisory committee appointed by the International Agency for Research on Cancer – the cancer agency of the World Health Organization – to classify processed meat as a Group 1 carcinogen in 2015.

An agent is classed as a Group 1 carcinogen when there is convincing evidence that the agent causes cancer – in the case of processed meat, colorectal cancer – in humans, rather than simply being associated with cancer. This places salted, cured, fermented and smoked meat (including hot dogs, ham, bacon, sausage, and some deli meats) in the same category as tobacco smoking, asbestos and plutonium.

The IARC classified red meat (beef, pork, mutton, lamb and goat) as a Group 2A carcinogen which means it probably causes cancer in humans (specifically colorectal cancer, with some evidence that it also causes prostate and pancreatic cancer).

Since then, even more evidence has accumulated, indicting red and processed meats as carcinogenic to the human colorectum (see here and here): for every extra 100 g of red and processed meat eaten per day, the risk of colorectal cancer increases by 12%.

But there is now also convincing evidence that red meat intake is linked to cancer of the lung, oesophagus and stomach and substantial evidence that it is linked to breast and endometrial cancers and non-Hodgkin’s lymphoma; while processed meat is strongly associated with oesophageal, stomach and bladder cancers, and these risk increases were not considered by the QIMR Berghofer Medical Research Institute team when they calculated that 40% of cancer deaths in Australia could be prevented.

Nor did they consider the strong evidence that dairy product consumption increases the risk of prostate cancer, the third leading cause of cancer death in Australia

And of course, because their analysis was grounded in the reductionist paradigm that underpins practically all published scientific research – that is, each possible risk factor is considered in isolation to all other risk and protective factors, they did not even attempt to grapple with the question,

“By how much could we reduce our cancer death rate if every baby in Australia was breastfed exclusively for 6 months, then continued on breastmilk for 1-2 years while being weaned onto a nutritious plant-based diet with ample fruit and vegetable consumption; got regular physical activity throughout their entire lifespan; maintained a healthy bodyweight from infancy to old age; never smoked or was exposed to passive smoke; drank alcohol rarely or not at all; obtained sufficient sunlight exposure to meet their vitamin D needs but never suffered sunburn; breastfed their own babies for 1-2 years; and never took hormonal drugs or other pharmaceuticals known to increase the risk of cancer?”

With all of these diet and lifestyle factors positively influencing the expression of our genes, enhancing our DNA repair mechanisms, upregulating our immune system, and modulating our metabolism and endocrine (hormonal) system, not only would the majority of cancer deaths be prevented, but suffering and death from other common lifestyle diseases such as type 2 diabetes, chronic obstructive pulmonary disease and coronary heart disease.

I fully acknowledge, this is a lofty target to aim at, and many of us are at a point in our lives where our own choices, and our parents’ choices, have already done some damage that cannot be undone when it comes to our risk for cancer. However, as a health practitioner I feel morally obliged to inform my clients of the risks their current diet and lifestyle choices entail, and the potential gains they can expect by making healthier choices.

Ultimately, it’s up to each individual to decide what he or she will do with the knowledge that science uncovers, day by day, about how our diet and lifestyle behaviours affect our cancer risk. But that knowledge should never be withheld because someone in authority thinks that “we can’t handle the truth”.

If you want to geek out on the science behind what causes cancer and how nutrition affects it, watch my webinar Eating to Beat Cancer. The Cancer Screening webinar in my EmpowerEd health and nutrition education program walks you through the scientific evidence on which cancer screening tests save lives, which do more harm than good, and which are unproven. And if you want my help in formulating a personalised plan to reduce your risk of cancer (including cancer recurrence, if you’ve already had it), apply for a Roadmap to Optimal Health consultation today.