Can cancer really be linked to diet?

Campbell Esselsyn and Ornish

Research scientists as early as the 1980’s (1,2) estimated that around 35% of cancers were causally linked to dietary factors, with some researchers now suggesting that it is closer to 70% (3). Whether the lower or higher figure, if these estimates are correct, then why are the majority of people continuing with their conventional diets without stopping to find out whether they are eating themselves into chronic ill health, ending in a potentially avoidable early death? This is particularly poignant when you consider that cancer is one of the top two leading causes of death in the western world, along with heart disease.

Amongst those eminent scientists who consider that the 70% figure is closer to reality is Professor T Colin Campbell. He, Dr Caldwell B Esselstyn and Dr Dean Ornish are luminaries you will come across whenever you search for the leading pioneers of whole food plant-based nutrition, and much of my work is underpinned by their and other outstanding individuals’ invaluable research.

It has been shown, for instance, that even heavy smokers who ate a diet richer in beta-carotene (found predominantly in green leafy vegetables) were less likely to develop lung cancer than those heavy smokers who didn’t eat their healthy greens (4).

Dr Dean Ornish undertook some pioneering research into prostate cancer and how its progression might be affected by dietary/lifestyle changes (5). His results showed a significant and positive effect compared with the control group who did not make these changes to their diet and lifestyle. And which man wants to increase the risks of getting prostate cancer just because they can’t resist the temptation of fried eggs and bacon? Well, that’s the whole point – loads of them! And it isn’t necessarily their fault. Our society is so unaware of the relationship between diet/lifestyle and chronic killer diseases like cancer. It is hardly possible to pass a whole day without being assailed with adverts and other inducements that make us ignorant of the fact that the ‘Just Eat’ fast food campaign is anything but just, or that eating a Big Mac is anything other than a Big Mistake.

You might be interested in seeing Dr Dean Ornish interviewed – and his TED talk –

I will be looking more closely at specific research linked to diet and other cancers (particularly prostate and breast cancers) in subsequent blogs. Additionally, I will look at the particular foods that research has shown might be strongly beneficial for those who want to reduce cancer risk, as well as for those who are already diagnosed and want to do all they can to slow down (and hopefully reverse) the cancer progression.



  1. Armstrong B, Doll R. Environmental factors and cancer incidence and mortality in different countries, with special reference to dietary practices. Int J Cancer. 1975;15:617-31.
  2. Doll R, Peto R. The causes of cancer: quantitative estimates of avoidable risks of cancer in the United States today. J Nat Cancer Inst. 1981;66:1191-308.
  3. T Colin Campbell. Module 1.4 Nutrition & Data Behind the Ten Leading Causes of Death. eCornell University Nutrition and Society CNS601_20180117_01, Certificate Course in Plant-Based Nutrition, Nutrition. 2017.
  4. Peto R, Doll R, Buckley JD, Sporn MB. Can dietary beta-carotene materially reduce human cancer rates? Nature. 1981;290:201-8.
  5. Ornish D, Weidner G, Fair WR, et al. Intensive lifestyle changes may affect the progression of prostate cancer. J Urol. 2005;174:1065-9; discussion 9-70.