Alcohol Is A Carcinogen

Since April is Alcohol Awareness Month, I wanted to share one thing I recently learned about alcohol - it's a carcinogen.

"The International Agency for Research on Cancer of the World Health Organization has classified alcohol as a Group 1 carcinogen. Its evaluation states, "There is sufficient evidence for the carcinogenicity of alcoholic beverages in humans. …Alcoholic beverages are carcinogenic to humans (Group 1)."

"Alcohol is associated with an increased risk of a number of cancers. Breast cancer in women is linked with alcohol intake. Alcohol also increases the risk of cancers of the mouth, esophagus, pharynx and larynx, colorectal cancer, liver cancer, stomach and ovaries."

- Alcohol and Cancer

I knew that drinking alcohol increased the risk of some cancers, especially breast cancer. But I had no idea of the variety of mechanisms. From Wikipedia's Alcohol and Cancer page:

"In a review, Pöschl and Seitz list some possible mechanisms of alcohol as a carcinogen:

• local effects of alcohol
• metabolism to acetaldehyde (which may be mutagenic at physiologically meaningful levels[17])
• induction of CYP2E1
• nutritional deficiencies
• interactions with retinoids
• alcohol and methylation
• alcohol and immune surveillance

Purohita et al. propose an overlapping list:

• production of acetaldehyde, which is a weak mutagen and carcinogen
• induction of cytochrome P450 2E1 and associated oxidative stress and conversion of procarcinogens to carcinogens
• depletion of S-adenosylmethionine and, consequently, induction of global DNA hypomethylation;
• induction of increased production of inhibitory guanine nucleotide regulatory proteins and components of extracellular signal-regulated kinase–mitogen-activated protein kinase signaling
• accumulation of iron and associated oxidative stress
• inactivation of the tumor suppressor gene BRCA1 and increased estrogen responsiveness (primarily in breast)
• impairment of retinoic acid metabolism

Boffetta and Hashibe list plausible mechanisms as including:

• a genotoxic effect of acetaldehyde
• increased oestrogen concentration
• a role as solvent for tobacco carcinogens
• production of reactive oxygen species and nitrogen species
• changes in folate metabolism

This bit is unbelievable:

"Individuals who both smoke and drink are at a much higher risk of developing mouth, tracheal, and esophageal cancer. Research has shown their risk of developing these cancers is 35 times higher than in individuals who neither smoke nor drink. This evidence may suggest that there is a cocarcinogenic interaction between alcohol and tobacco-related carcinogens."

35 times! It sure puts the contribution of diet into perspective.
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