The physicians determined exposure to soot in the chimneys had caused the cancer. Once the sweeps wore protective clothing and routinely cleaned the soot off their bodies, the cancer rate dropped. Asbestos is another occupational carcinogen. Occupational exposure might be related to up to 5 percent of cancer deaths. Diet Foods such as hot dogs, bacon, ham and pickled meats and fish have preservatives called nitrites.
Nitrites convert to another chemical called nitrosamines, which are known cancer-causing agents.
Researchers have linked an increased risk of stomach cancer to overconsumption of smoked or cured foods. Eating such foods only occasionally is not harmful. Researchers have linked a diet high in calories and fat to an increase in cancer. People in the United States consume more fat than in other countries, resulting in a higher incidence of breast cancer and colon cancer. Consuming large amounts of refined sugars with a high-fat diet increases the risk of developing colon cancer.