What Causes Cancer?

What causes cancer? When you think of all the things that are known or assumed to be cancer-causing and put them together–you end up with a list that is pretty daunting. This summary comes straight from the book Cancer: 101 Solutions to a Preventable Epidemic (New Society Publishers, 2007) by Liz Armstrong, Guy Dauncey and Anne Wordsworth.

This list does not claim to represent a complete summary of the contributing factors; but it is an indication that there are many more factors than we usually think about. The good news is that many are avoidable. What do you think of this list? Do you take issue with any of the items here? Are there other items that you would add?

Lifestyle and Diet Factors
• Smoking and second-hand smoke.
• Diet–too much meat, not enough fruits and vegetables.
• Suntanning.
• Absence of UV sunlight in some regions, reducing cancer-protecting vitamin D.
• Obesity, and lack of regular exercise.

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Other Food Factors
• Processed food such as nitrosamines, aspartame, some food colorants.
• Bovine growth hormone in milk.
• Some salt-cured, pickled, and smoked food.
• Sugar and alcohol consumption.
• Absence of cancer-protecting compounds in food not grown organically.
• Food contaminated with pesticides and herbicides.

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Next: Work, Radiation and Air Pollution

Occupational Hazards
• Workplace exposure to carcinogens including solvents, heavy metals, radiation, pesticides, diesel fuel, benzene, asbestos.

• Solar UV radiation from ozone depletion.
• Ionizing radiation from diagnostic x-rays, especially CT scans and mammograms; nuclear medicine, radiation therapy.
• Electromagnetic radiation from power lines, cell towers, cellphones, electronic devices (both wired and wireless).
• Ionizing radiation from uranium mining, nuclear power plants, atomic bomb tests, depleted uranium.

Air Pollution
• Carcinogens such as benzene, diesel vehicle exhaust, coal-fired power emissions, asbestos fibres, industrial chemicals, incinerators, pesticides, soot, wood dust, indoor air pollutants.

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Next: Water, indoor toxins, and natural carcinogens

Water Pollutants
• Carcinogens such as chlorine by-products, industrial chemicals, heavy metals, pesticide residues, fluoride, arsenic, hormone-disrupting chemicals, coal-fired power wastes.

Toxic Products
• Toxic chemicals in household products such as cosmetics, fire-retardants, non-stick agents, solvents, cleaning products, building products.
• Plasticizers such as bisphenol A and phthalates in various plastic food containers, water coolers and bottles, children’s toys, teethers, dental sealants, canned foods.
• Some drugs including immunosuppressants, birth control pills, hormone pills, hormone replacement therapy, androgenic steroids, anti-depressants, proton pump inhibitors, behavior modifying drugs and drugs used to treat cancer.

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Natural Carcinogens
• Foods contaminated with fungal aflatoxins.
• Various phytochemicals in food.
• Chewing betel nuts.
• Radon gas leaking into buildings.
• Cosmic and solar radiation.

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Next: Infections, Hormone Disrupters, and more

Infectious Agents
• Infectious agents such as hepatitis B and C, HIV, human papilloma virus.

Reduced Immunity
• Toxic substances that weaken the immune system’s ability to fight cancer.

Endocrine/Hormone Disrupters
• Endocrine disrupting chemicals in air, water, and consumer products.
• Increased exposure to a woman’s (endogenous) estrogens.
• Loss of darkness related to rotating shift work, reducing cancer-protecting hormone melatonin.

Other Factors
• Windows of vulnerability: Exposure to toxic substances pre-conceptually, in utero, during infancy, during puberty.
• Family history of cancer–shared habits, shared pollution, shared genes.
• Parental and grandparental exposure to contaminants, causing faulty epigenetic expression.
• Poverty.
• Living near toxic sources.
• Genetic variability–some people are more vulnerable than others.

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Lacey J.
Lacey Jo3 years ago

People should stop smoking.

Fi T.
Past Member 3 years ago

Lifestyle matters

tin leng lim
tin leng lim4 years ago

Peoples should stop smoking.

greenplanet e.
greenplanet e4 years ago

Good info.

Peter A.
Past Member 4 years ago


Amandine S.
Past Member 4 years ago

Thanks for the article.

Terry V.
Terry V4 years ago

ban breathing

Eternal Gardener
Eternal G6 years ago

You can't narrow this down, it depends literally on everything.

Maria Papastamatiou

I very much fear that we are still in the beginning of understanding what causes cancer. My mother was a fanatic vegan, did not smoke or drink alcohol, ate organic food, did not have cancer in the family, but had a huge fear of getting cancer. And she did... Conclusions are yours!

Annemarie W.
Annemarie L6 years ago