Evidence points to beta carotene being one example of such a compound, which has led researchers to caution against the emphasis on isolated dietary supplements and instead recommend a focus on promoting a diverse diet rich in fruits and vegetables.
[4][5] The International Agency for Research on Cancer (IARC), established in 1965 as a subunit of World Health Organization, classify carcinogens into four groups.
[7] Co-carcinogens can be a lifestyle like cigarette-smoking, alcohol-drinking or even areca nut tobacco-chewing, which is an Asian tradition, because those activities promote the cytopathic effect (CPE).
[10] Experiments for human toxicology require a long term following and a large amount of investment in order to classify a chemical as an co-carcinogen, carcinogen, or anti-carcinogenic.
[citation needed] Some myths even state beta carotene[11][failed verification] as elixir in developing countries (the Third World).