LE Magazine April 2003
Carcinogens Are Everywhere,
But Do You Have To Worry?
A growing number of Americans are modifying their lifestyle to avoid exposure to toxic chemicals.1 Those seeking to maintain good health are staying away from cigarette smoke, tap water, gene-mutating foods and other carcinogen carriers.
Despite these heroic efforts, two newly released studies show that our bodies have become toxic chemical repositories.
After decades of studying carcinogens in air, water and food, scientists can now measure the magnitude of chemical contamination in human beings via blood and urine tests.2 It turns out that even health conscious people have become significant pollution sites.
The first study was led by Mount Sinai School of Medicine in New York and tested for 210 different chemicals.3 This was the largest analysis of commonly found industrial chemicals ever surveyed in humans. The findings revealed that the subjects contained an average of 91 compounds, most of which did not exist 75 years ago. Of these toxic compounds, 76 of them have been linked to cancer and all test subjects carried them. There was a high prevalence of polychlorinated biphenyl (PCB) contamination, a potent carcinogen that was banned in the U.S. in 1976, but is used in other countries and resides in the environment for decades.
The second study was conducted by the Centers for Disease Control and Prevention (CDC).4 That study provided statistical data relevant to U.S. body burdens of 116 different chemicals and confirmed many of the findings of the first study. Taken together, these two independent studies document that the bodies of U.S. citizens have become contaminated with a myriad of lethal chemicals. When one considers the hundreds of billions of dollars spent by the Environmental Protection Agency (EPA), the Food and drug Administration (FDA) and other regulatory agencies, it becomes acutely obvious that the government has utterly failed to protect the public from exposure to these environmental carcinogens.
In a statement released by a non-profit organization called the Environmental Working Group (which organized the first study), they declare:
"People are loaded with chemicals. Some are known carcinogens, and many are banned. There are some about which science knows virtually nothing when it comes to potential health effects. We need a modern, common sense approach to identifying and protecting the public from possible health effects from long-term exposure to low levels of multiple chemicals."5
A contrary view
Dr. Bruce Ames is considered one of the foremost experts on gene mutation. One of Dr. Ames' most notable accomplishments is the invention of the "Ames test" that measures the gene mutating effects of different compounds, such as environmental carcinogens.
Dr. Ames has extensively published material about natural carcinogens that cause cancer in laboratory rodents, or have been shown to mutate genes when tested with bacteria (Ames test).6
It is Dr. Ames' contention that even if we could eliminate all synthetic carcinogens, we would still be exposed to many other natural carcinogens through our diet.6 According to Dr. Ames, there are naturally occurring chemicals even in the healthy food we eat that have either been shown to be carcinogenic in laboratory rodents or have been shown to be "mutagens" because they can damage DNA genes. Mutagens can also be thought of as possible carcinogens.7,8,9 Mutagen tests such as the Ames test are often used as quick indicators to predict how likely a chemical is to cause cancer.
It has become clear that many naturally occurring chemicals, which are plentiful in our food supply, cause cancer in rodents when fed in high doses over the animal's lifetime.10
For example, plants that humans eat produce natural pesticides that throughout evolution have enabled them to survive insect attack. Human dietary intake of these natural pesticides is about 10,000 times higher than human intake of synthetic pesticides (classified as rodent carcinogens.)6 In other words, consumers who choose to worry about eating synthetic chemicals shown to cause cancer in rodents should understand that the human diet is full of naturally occurring chemicals also shown to cause cancer in rodents.11
Dr. Ames and his associates do not believe that the residues of synthetic rodent carcinogens in our diet are likely to pose a risk of cancer in the quantities we consume on a daily, monthly, or yearly basis.12 Conversely, they point to the many naturally occurring carcinogens that are natural pesticides-chemicals that plants produce to repel or kill predators. Of the approximately ten thousand such natural pesticides occurring in the diet, only about 60 have been tested in rodent experiments. These chemicals are found in a wide variety of our food plants: Brussels sprouts, cantaloupe, cauliflower, cherries, chili peppers, cocoa, garlic, grapes, kale, lentils, lettuce, and radishes-to name just a few.
Dr. Ames believes that the consumption of small doses of rodent carcinogens, whether of natural or synthetic origin, is unlikely to pose a cancer hazard to humans.13,14,15 The simple fact is that carcinogens and mutagens are everywhere in Mother Nature's own food supply.
Dr. Ames casts doubt on the true danger of rodent carcinogens based on how the rodent studies were done in relationship to what humans would consume in the real world. For example, bread contains a potent rodent carcinogen called furfural. But when the difference in body weight between a human and a rodent is taken into account, based on the data available from the laboratory, a person would have to eat 82,600 slices of bread per day for years to consume an amount of furfural equal to the amount that increased the risk of cancer in rodents.
Reducing food intake
Dr. Ames does point a finger at the high calorie diet that has become commonplace in the United States. A consistent intake of excessive calories contributes to obesity, with its associated higher risk of heart disease, cancer and many other diseases.16 Interestingly, excessive caloric intake has been called the "most striking" carcinogen in rodent carcinogenicity studies. Body weight is a good predictor of a rat's risk of cancer as shown in comparisons of rats on calorie-restricted diets versus those on an unrestricted diet (rats permitted to eat all they want.)
According to Dr. Ames, in our quest to reduce cancer risk by manipulating our diet, we should focus on dietary imbalances in what we eat, not on trace chemicals.17 Numerous epidemiological studies have indicated that people who consume a diet high in fruits and vegetables have a lower risk of various types of cancer.18 This is true in spite of the fact that natural chemicals that are also rodent carcinogens occur abundantly in many of these same fruits and vegetables.19 Note that the population studied lowered their risk of cancer even though their food presumably contained synthetic pesticide residues, suggesting that high fruit and vegetable consumption was still protective against cancer.20
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