What Are Carcinogens, Really?

For hundreds of years, scientists have believed that certain substances could cause tumors. John Hill, a physician in the 18th century, first made the connection between tumors and tobacco in 1761. In 1915, physician Yamagiwa Katsusaburo and his assistant, Koichi Ichikawa investigated chemical carcinogens. This knowledge has helped modern scientists identify cancer-causing agents.

Carcinogens cause numerous forms of cancer, often depending on the type of agent ingested or absorbed. For example, the human papillomavirus (HPV) can cause cancer in the vulva, anus, vagina, penis, cervix, throat, and mouth. Carcinogens interact with the body on a cellular level and damage DNA. Mutations in DNA increase susceptibility to some cancers.

Carcinogenic substances don’t always cause cancer. Sometimes a person must be exposed to a certain degree or in a certain manner to develop cancer from a carcinogen. At other times, genetics plays a role in determining the adverse effects of these chemicals.

Some carcinogenic substances naturally occur in food. For example, some grains and nuts contain aflatoxins, a substance found in fungi that grow on these foods. Eating contaminated produce, meat, or dairy can expose you to these carcinogens. Other carcinogenic foods include processed meats and alcoholic beverages.

Cigarettes are a serious carcinogenic item because of their tobacco content. Sunlight contains ultraviolet rays, which are a carcinogen. The International Agency for Research on Cancer, a division of the World Health Organization, classifies lead as a possible carcinogen, as well. Asbestos, which was once used for insulation and imitation-slate roofing, is also classified as a carcinogenic substance.

In addition to sunlight, other substances that occur in the environment can cause cancer in humans, such as arsenic. Some people are exposed in small amounts through drinking water. These amounts aren’t large enough to kill them but can damage their genetic structure. Although limited information is available, it’s possible that aristolochic acids, which are found in some plants used to create herbal medicines, could be carcinogenic.

While it may seem that everything is a carcinogen, most substances are not. In addition, most substances that research shows to be [citation href="https://pubmed.ncbi.nlm.nih.gov/3575799/" title=Regulatory Toxicology and Pharmacology" desc="Everything Is a Carcinogen?"]carcinogenic to animals do not affect humans in the same way when exposure is at normal levels. Sunlight, for example, is not harmful when people take proper precautions, such as using sunscreen.

Some scientists believe that fetuses exposed to carcinogens during the late stages of pregnancy can develop alterations in the genetic code and pre-program genes, increasing susceptibility to cancer in childhood, young adulthood, and middle age. Some carcinogens, like formaldehyde, can cause fertility problems and potentially threaten human health, especially when exposure is repeated.

Many governments have regulations around dangerous substances, including some carcinogens, like arsenic. Environmental carcinogens are more heavily regulated than others, and some cannot be controlled by authorities. In Europe, research identifies strategies for controlling carcinogenic exposure. Researchers there push for further regulations on prime cancer-causing suspects. Some scientists want authorities to regulate probable carcinogens like acrylamide and force the discontinuation of their use.

While carcinogens can seem alarming and pervasive, there are simple ways to limit your exposure and protect yourself. For example, eating healthy and practicing safe sun exposure can reduce the effects of many toxic substances. If you have to handle carcinogenic substances in your workplace, learn the proper ways to handle them. Avoid the use of pesticides in gardens, and weed by hand instead. Taking these and other safety precautions can limit your carcinogen exposure and reduce your risk of cancer.