© Diet For a New America, John Robbins, Stillpoint
(1) A Diet and Disease:
Human population studies have identified the link between the high fat (Western) diet and cancer of
Animal experiments have also given contradictory results in studies of diet and cancer. Epidemiological research has shown that too much fat in the diet can cause cancer of the colon with saturated fat the chief culprit. However, according to animal tests, it is the unsaturated fats that are the most dangerous.38 With regard to dietary fibre, animal research is again confusing with some experiments showing a reduced risk of cancer and others an increased risk.39 The human evidence, which is all that matters, suggests that fiber can protect against cancer of the colon. But the absurdity of animal experiments is especially highlighted by tests carried out on the natural substances present in fruit and vegetables.40 These chemicals have been evolved by the plant as a defense against predators and parasites. When tested on rats and mice at high doses, many of these substances were shown to cause cancer. Yet it is well known from human experience that diets rich in fruit and vegetables actually reduce the risk of cancer!
Nevertheless, proponents of animal tests argue that they do have validity since nearly all human carcinogens have (eventually) been shown to cause cancer in some species of animal. But this is misleading: if substances like asbestos, tobacco, arsenic, benzene, alcohol, naphthylamine and soot were not already known to be human carcinogens, scientists would not have persisted with attempts to induce the disease in animals. Reliance would have been placed on one or two routine feeding or inhalation tests of the type to which new chemicals are now submitted. As a result, many of the most dangerous human carcinogens would have been deemed safe. For new substances, where epidemiology has had no opportunity to assess risks, researchers should be calling for more reliable test systems rather than a continuation of the biologically flawed approach with rats and mice.
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