Here’s another study that addresses, not just amount of alcohol consumed, but frequency … how many days a week one drinks at all. It’s much bigger than the one I just posted. It analyzed data from 88,746 men and women from Japan and found the same thing, that drinking alcohol every day can shorten life:
Patterns Of Alcohol Drinking And All-Cause Mortality: Results From A Large-Scale Population-Based Cohort Study In Japan, American Journal of Epidemiology, May 2007
The deleterious effects of alcohol seem to be mitigated by abstaining for a few days a week. The Japanese call this a “liver holiday,” which “is considered important for general health and for maintaining the metabolic function of the liver.”
This study defined a heavy drinker as someone who consumed more than 300 grams of ethanol a week. I had to run the numbers to understand that:
- 5 ounces of wine at 12% alcohol is 0.6 ounces or about 17 grams ethanol.
- 12 ounces of beer at 6% alcohol is 0.72 ounces or about 20 grams ethanol.
300 grams works out to 2.5 glasses of wine a day (a small glass: 5 ounces) or 2 glasses of beer a day (12 ounces). If you drank this amount or more, you were considered a heavy drinker.
However, in the US, a heavy drinker (from the US Cancer Prevention Study) was someone who consumed more than 30 g of alcohol per day, so more than 9 ounces of wine (a little less than 2 glasses) or 1.5 beers.
“The highest hazard ratios [were] observed among those consuming ≥450 g of alcohol 5–7 days per week.”
That about 3.5 small (5oz) glasses of wine or 3 (12oz) beers a day. That was the riskiest.
“The increased risk of all-cause mortality associated with frequency of alcohol intake was seen among heavy drinkers only (≥300 g alcohol/week).”
That’s telling. It says that if you drank less than 2 drinks a day, you didn’t experience increased risk, in this study at least.
This following bit is interesting … The researchers found that most of these alcohol-related deaths were from cancer. What’s the mechanism? The NIH says that the body first…
“… metabolizes alcohol to acetaldehyde, a highly toxic substance and known carcinogen. Then, in a second step, acetaldehyde is further metabolized down to another, less active byproduct called acetate, which then is broken down into water and carbon dioxide for easy elimination.”
So, the more you drink, and the more often you drink, the more you expose your tissues (especially liver, pancreas, and brain) to acetaldehyde, “a known carcinogen.”
I imagine that future guidelines for alcohol consumption in the US will address frequency as well as amount, incorporating “three alcohol-free days a week” into the “1 drink for women and 2 drinks for men” advice. … As long as the wine, beer, and spirits lobbies don’t nip it.