Environmental chemicals not main cause of cancer

Regarding the very specialised, complicated and in many areas poorly understood cause of cancer (and breast cancer in particular), Helen Muscat (June 27) quotes the Health and Environmental Alliance.

To my knowledge this organisation has carried out no research of its own, nor presented peer-reviewed research that contradicts the finding of past animal experiments conducted by T. Colin Campbell PhD, which showed that the amount of animal protein in laboratory animals' diet determines whether or not they develop cancer when exposed to potent chemical carcinogen.

None of the animals exposed to chemical carcinogens, but fed a mainly plant-based diet, developed cancer, but all the animals exposed to similar carcinogens, but with 20 per cent or more animal protein in their diet, all developed cancer - very clear-cut scientific findings which replicated the findings of previous experiments in India.

If someone is wondering what laboratory rats have to do with humans, apart from the fact that rats and humans are very similar biologically, modern medicine demands that any new medical theory or drug needs to be first tested and proven in an animal model of the disease in question.

Dr Campbell later went on to show, with Chinese researchers, that in parts of China which were vegetarian, people suffering from cancer, heart disease and diabetes were low while in parts of China with substantial amounts of animal-based foods in their diet, people had high incidences of cancer, heart disease and diabetes.

Even earlier, other American researchers had shown that when Japanese or Koreans emigrated to the US, their previously very low rates of breast cancer rose (within one generation) to reach the high rates of other Americans.

Although this finding could be due to higher environmental pollution in the US, it is more likely to be linked to a change of previously mainly vegetarian diets, and possibly also increased stress of living in a new environment. Interestingly, the importance of chronic stress in cancer promotion has been demonstrated in laboratory animals made susceptible to cancer - the ones kept stressed by various means, develop cancer earlier and their cancer grows faster than in unstressed similar animals.

Environmental pollution needs to be closely monitored but the evidence so far suggests that it's not likely to be the major factor in breast cancer causation.

Plant-based foods have cancer preventing chemicals we are only now beginning to discover, and it is far easier for people reluctant to eat more vegetables and fruits, and less meats and dairy produce, and reluctant to exercise, to blame cancer on environmental chemicals (but the dangers of smoking are real enough).

Dr Campbell, who was on the American National Academy of Sciences Expert Panel on Food Safety Policy, and was one of the first scientists to isolate dioxin, states in the introduction of his recent book, The China Study (ISBN 1-932100-66-0), that "synthetic chemicals in the environment and in your food, as problematic as they may be, are not the main cause of cancer".

If the people at HEAL haven't read this book, it's about time they did, because one can easily miss the wood for the trees by ignoring the science of past decades.