Cannabis alters human DNA

This is no surprise. Any kind of smoke is damaging. And some will be more so than others.

http://www.eurekalert.org/pub_releases/2009-06/uol-ah061609.php

Public release date: 16-Jun-2009
Contact: Rajinder Singh
University of Leicester

A new study published by University of Leicester researchers has found "convincing evidence" that cannabis smoke damages DNA in ways that could potentially increase the risk of cancer development in humans.

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"There have been many studies on the toxicity of tobacco smoke. It is known that tobacco smoke contains 4000 chemicals of which 60 are classed as carcinogens. Cannabis in contrast has not been so well studied. It is less combustible than tobacco and is often mixed with tobacco in use. Cannabis smoke contains 400 compounds including 60 cannabinoids. However, because of its lower combustibility it contains 50% more carcinogenic polycyclic aromatic hydrocarbons including naphthalene, benzanthracene, and benzopyrene, than tobacco smoke."

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The authors added: "It is well known that toxic substances in tobacco smoke can damage DNA and increase the risk of lung and other cancers. Scientists were unsure though whether cannabis smoke would have the same effect. Our research has focused on the toxicity of acetaldehyde, which is present in both tobacco and cannabis."

The researchers add that the ability of cannabis smoke to damage DNA has significant human health implications especially as users tend to inhale more deeply than cigarette smokers, which increases respiratory burden. "The smoking of 3-4 cannabis cigarettes a day is associated with the same degree of damage to bronchial mucus membranes as 20 or more tobacco cigarettes a day," the team adds.

"These results provide evidence for the DNA damaging potential of cannabis smoke," the researchers conclude, "implying that the consumption of cannabis cigarettes may be detrimental to human health with the possibility to initiate cancer development."