Transcript: Breast Cancer & Alcohol: How Much is Safe?
Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.
Recently, the IARC, the International Agency for Research on Cancer, the official World Health Organization body that decides what is and is not cancer-causing, concluded that alcoholic beverages—all alcoholic beverages—are to be considered “carcinogenic to humans.”
“[M]ost recent research has focused on acetaldehyde, the first and most toxic [alcohol] metabolite, as a cancer-causing agent.” Seems that bacteria in our mouths oxidize alcohol into this carcinogen called acetaldehyde, which we then swallow.
“There is convincing evidence that alcohol consumption increases the risk of [breast] cancer…” But: “Most of the data derive from studies that focused on the effect of moderate/high alcohol intakes, while little is known about light alcohol drinking (up to 1 drink/day).”
Hence, this new meta-analysis of studies that compared light drinkers to non-drinkers, and found “a moderate but significant association with breast cancer, based on the results of more than 100 studies.”
They estimate that about 5,000 breast cancer deaths a year are “attributable to light drinking”—meaning nearly 5,000 women that died of breast cancer maybe wouldn’t have, if they had just stayed away from alcohol completely, leading to an editorial in the medical journal Breast that concluded “women who consume alcohol chronically have an increased risk for breast cancer that is dose dependent but without threshold.” Meaning there’s apparently no level of alcohol consumption that doesn’t raise breast cancer risk at least a little. So, no “safe threshold. Any level of alcohol consumption appears to increase the risk of developing an alcohol related cancer.”
For example, the Harvard Nurses’ Study found that even consumption of less than a single drink per day may be associated with a modest increase in risk. Forget a single drink; what about “a single sip?” A new study found that even holding a teaspoon of hard liquor in your mouth for 5 seconds—and then spitting it out—results in “carcinogenic concentrations of acetaldehyde…produced from [the alcohol] in the oral cavity instantly after a small sip of strong alcoholic beverage, and the exposure continues” for about 10 minutes after spitting it out. And, you didn’t even drink it!
Even alcohol-containing mouthwash can give you a carcinogenic spike. The researchers conclude: “All in all,…there is a rather low margin of safety in the use of alcohol-containing mouthwash. Typical use will reach the concentration range… above which adverse effects are to be expected. Till the establishment of a more solid scientific basis for a threshold level of acetaldehyde in saliva, prudent public health policy would recommend generally refraining from using alcohol in such products.”
So, why isn’t the same recommendation made for alcoholic beverages? Well, as the Harvard paper concludes, individuals “will need to weigh the risks of light to moderate alcohol use on breast cancer development against” the benefits for heart disease prevention “to make the best personal choice regarding alcohol consumption.” They’re talking about the famous J-shaped curve. While smoking is bad, and more smoking is worse, and exercising is good, and more exercise is better, for alcohol, there appears to be this beneficial effect of small doses. A six-pack a day raises overall mortality, but so does teetotaling.
The #1 killer of women isn’t breast cancer; it’s heart disease, and a drink a day reduces the risk of heart disease. Why just reduce the risk of heart disease, though, when you may nearly eliminate the risk of heart disease with a healthy diet? So, a plant-based diet that excludes certain plant-based beverages may be the best for overall survival.
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