Cancer, as the curve adapted here from the Ames publications suggests, is an ordinary mechanism for the end of human life. As can be seen from this curve, more than 20% of those who live to be 80 years old die from cancer. It is possible that cancer cannot be eliminated with current technology. It is likely, however, that it can be postponed, so that death usually results from other causes. To the average person, cancer seems to strike suddenly, horribly, and tragically without warning. Although each person knows that his life will end, the onset of cancer moves that end closer and gives it a reality that removes human mental defenses against the fact of mortality. Fear, especially fear of cancer, is a powerful force for the manipulation of human beings. For this reason, many groups use fear of cancer in an effort to further their agendas. Pseudoenvironmentalists have been especially unscrupulous in the promotion of fear of cancer as has the Environmental Protection Agency (EPA), a vast regulatory bureaucracy that has been essentially built by manipulating public fear. Recent issues of
Bruce Ames and his colleagues and coworkers have focused on another cancer fear - the fear that trace levels of industrial chemicals increase the risk of cancer. As in the case of radiation, harmful effects of chemicals at very high doses have been extrapolated to low dose ranges where harmful effects have not been actually observed. As in the radiation case, it turns out that the sum of government actions taken in response to claimed dangers of trace chemical exposure have actually increased rather than decreased cancer risk.
Although not yet completely understood, the development of cancer is apparently a several stage process.
First, damage is done to the nucleic acid molecular library in a living cell, so that the cell forgets information essential to doing its job without disruption of the work of other cells. This damage also gives the cell a competitive advantage over undamaged cells. Single instances of damage are usually of little importance, however. Cellular mechanisms repair or eliminate such damage very efficiently. This is necessary, because great amounts of chemical damage occur in the course of ordinary biochemical life. Ames and coworkers found, for example, that the average number of ordinary biochemical instances
of oxidative nucleic acid damage in the rat is about 100,000 per cell per day. Nevertheless, if carcinogens substantially increase the amount of nucleic acid damage, this presumably increases the number of potentially precancerous events that require repair.
Second, if the damaged cell manages to reproduce before it is either repaired or killed by intercellular or extracellular defenses, it may establish itself as a growing tissue of similarly damaged cells. Therefore, factors that substantially increase the rate of cell turnover in a living tissue would be expected to increase the chance that a damaged cell could establish itself as a mutated tissue.
Third, mutated cells must evade the body's immune system, which is trained to recognize cells that are not identical to those of ordinary tissue. Although this is more difficult in the case of cells arising from mutation of ordinary tissue as compared with invading cells such as bacteria, it is thought that the immune system does successfully recognize and eliminate many mutated cells. Anything that decreases the health of the immune system would be expected, therefore, to weaken this defense against cancer.
Fourth, growing mutated tissue often releases cells that establish themselves as growing cancer tissues in other parts of the body. These metastasized tissues multiply the number of locations in which the initial cancer can do harm.
Fifth, the primary cancer tissue or one of its metastases grows large enough to fatally disrupt an essential bodily function. Most cancer therapy focuses on surgical removal of cancer tissue or on slowing or reversing its growth. A very long time can elapse between the establishment of a cancerous tissue and its disruption of bodily functions great enough to allow detection. This lag time can be as much as 20 years or more. Thus, a cancer victim can be ill for many years before symptoms appear. Both the primary tumor and many metastases are often well developed before illness is discovered.
Cancer research focuses on 1) reduction of production of cancer cells through mutation and cell turnover, 2) increase in systemic resistance to the establishment of initial cancer cells as growing tissues, 3) reduction of rate of growth of cancer tissues once they have been established, and 4) techniques for selective destruction of cancer tissues.
Smoking and chronic infections are known to markedly increase cancer risk. It is believed that they do this by increasing the amount of intracellular nucleic acid damage and thereby increasing the probability that a cell will divide at a time when it has unrepaired, potentially cancerous genetic damage. Although chronic infections are largely a risk factor in underdeveloped countries, smoking is the greatest American risk factor.
Lung cancer is by far the most prevalent cause of death from cancer. Most lung cancer is caused by smoking. Smoking also increases the risk of other fatal diseases. On average, each pack of cigarettes smoked per day reduces life expectancy about 8 years. This reduction is a compression of life, not a loss of only the later years. Smokers age and die at an overall accelerated average rate. Although this effect is reduced for cigars and pipes, it is still substantial.
Diet is also an important cancer risk factor. Epidemiological studies show generally that cancer risk is increased for diets rich in fats and low in fruits and vegetables. For example, Ames quotes Block, Patterson, and Subar,
Nutr. Canc. 18, pp 1-29 (1992) who summarized this effect from 172 published studies. The averaged result of these studies is that the relative risk of cancer was reduced by about a factor of 2 by diets higher in fruits and vegetables.There is a hypothesis that fruits and vegetables reduce cancer risk because they contain substances which react with other molecules that might otherwise damage cellular nucleic acids. This has led to a widespread practice of food supplementation, especially with vitamins A, E, and C. While these substances may well improve health when taken in reasonable amounts, they are probably not a complete substitute for dietary fruits and vegetables. Regardless of how they work, however, it is well established that a diet rich in fruits and vegetables and low in fats decreases cancer risk.
| This provides an example of America's "wildcard'' phenomenon. Last month a fire in Boston claimed the life of an 85 year-old lady named Ann Wigmore. Although knowledge about the health benefits of fruits and vegetables can be traced to the beginnings of medical literature and then further back into the medical folk lore of many cultures, it was Ann Wigmore who raised American awareness of these facts to the critical point where scientists began to study them. As a child in Germany and Hungary during World War I, Ann Wigmore was treated by her village doctor grandmother, who emphasized the value of fruits, vegetables, and grasses in medicine. Ann came to America at the age of 16 and, after experiencing the health effects of the ordinary American diet, devoted the rest of her life to the advocacy of raw fruit and vegetable diets especially in the prevention and treatment of cancer. She was not a scientist and had many odd interests, but her gradual impact upon the American health food subculture and, through it, upon American science was substantial. I remember well the day in 1976 when Edie Mae and Arnold Hunsberger (founder of U.S. elevator corporation and inventor of the glass elevator) came to see me at the suggestion of a Caltech student. They stated that Mrs. Hunsberger's life had been saved by Ann Wig-more, and they wanted to tell me about cancer and raw fruits and vegetables. Edie Mae Hunsberger had decided to devote the rest of her life to the advocacy with which Ann Wigmore had helped her. Part of my laboratory at the time consisted of a colony of 1000 mice in which we were studying dose response of several vitamins as a function incidence and severity of skin cancer in UV irradiated hairless mice. The Hunsbergers convinced me to add fruits and vegetables to these studies. During the next year and a half, we found and confirmed by repetition a 4-fold reduction of cancer in these mice as a result of a raw fruit and vegetable diet alone.Through her tireless work, Ann Wigmore created tens of thousands of American advocates of the value of fruits and vegetables in the reduction of cancer. These advocates gradually raised awareness high enough that many laboratories were influenced as was ours, and science took over. Ann Wigmore will probably not be remembered. She will not even be referenced in the scientific literature, because she wrote nothing that would pass peer review. It is, however, wildcards such as Ann Wigmore and Arn and Edie Mae Hunsberger that pointed cancer research in this valuable direction. |
Cancer risk is also increased in individuals with very high occupational exposures to carcinogenic agents. This risk is cumulative, so workers who smoke have a lower tolerance for carcinogens and are, therefore, at greater risk.
Ames states that hormone levels increase cancer risk. Breast cancer is correlated to human hormone levels, especially in women who do not bear children. It is thought that this may be due to increased cell turnover that is stimulated by hormones. This turnover increases the chance that a mutated cell will establish itself as a tissue before the mutation is corrected.
Bruce Ames has estimated, based on his knowledge of the current scientific literature, the approximate relative contributions of the various factors as causes of cancer. His estimates are given in the table.
But where is the radiation? Where are the pesticides, herbicides, and trace industrial chemicals? Where is that element from pseudoen-vironmentalist hell - chlorine? They are exactly where they belong. They are not of sufficient importance to be in the list.
| The Causes of Cancer | ||
| Smoking | 30% | |
| Unbalanced Diets (high fat, low fruits and vegetables) | 35% | |
| Chronic Infections (Mostly in poor countries) | 30% | |
| Hormones (Breast, Endometrial, etc.) | 25% | |
| Occupation (Mostly Asbestos in Smokers) | 2% | |
| Pollution (Mostly Heavy Air Pollution) | <1% | |
| Total (Because of multiple causes) | 122% | |
Ah, but the EPA and its enviro friends will say, "these are Ames estimates. We don't really know for certain that pesticides are safe, so let's just ban them anyway, so that no one will be harmed.'' Well, it happens that Ames is one of the world's foremost experts in the testing of chemical substances for cancer causing potential. His answer to the pesticide question is as follows:
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Vol. 21, No. 8
Newsletter: Access to Energy Newsletter Archive Volume: Issues Issue/No.: Vol. 21, No. 8 Date: April 01, 1994 05:56 PM (For actual publication date see newsletter.) Title: Economic Freedom
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