By Kay Quinn Healthbeat Reporter
St. Louis (KSDK) - It can be one of the most confusing pieces of your personal health puzzle.
When does how much alcohol you drink turn from a possible health benefit to a risk?
In this week's 8 Ways to Prevent Cancer segment, we answer the question, is alcohol the enemy when it comes to cancer?
When actor Michael Douglas was diagnosed with late-stage throat cancer, he quickly and openly blamed his history of heavy drinking and smoking.
Turns out, alcohol causes between three and five percent of all cancers in this country.
"Colon, large intestine, breast and particularly upper airways, head and neck," said Dr. Graham Colditz of the Siteman Cancer Center.
In those cases, the alcohol itself directly goes to work on the DNA of cells in the mouth and upper esophagus, opening the door to tumor development.
But the same changes can happen in other parts of the body too.
"For colon cancer," said Dr. Colditz, "we know that the actual metabolism of alcohol literally consumes or burns up some of the sources for DNA division and repair."
And there's even a direct link to breast cancer.
"When they're drinking alcohol after menopause," said Dr. Colditz, "their estrogen levels go up so that's a direct stimulatory effect on breast cells."
It typically takes years for these changes to happen. And in the meantime, medical science also touts the benefits of alcohol in lowering risk of heart attack and stroke.
Dr. Colditz says ultimately, it's not a black and white issue. "There's a trade off with alcohol which is why many organizations set an upper limit instead of saying none at all."
So, it comes back to moderation.
Dr. Colditz says that means no more than one drink a day for women and two drinks a day for men.