Random thought:
When I was in Italy, everyone drank alcohol after meals, saying "It's for digestion!" I found myself getting buzzed on wine, limoncello, and grappa nightly. Don't get me wrong; I like having an excuse to drink, but I wonder if alcohol really is a digestive aid.
The alcohol we consume in our "alcoholic beverages" is technically ethyl alcohol (ethanol, C2H6O). Alcohol has historically been used to treat a variety of things including stimulating appetite and aiding in digestion.
In the esophagus, alcohol reduces motility and relaxes the gastroesophageal sphincter (the opening between the esophagus and the stomach). So it slows down how quickly things travel through the esophagus, and it increases the risk for gastric acid to creep back up into the esophagus (gastric reflux), meaning it does not aid in digestion in the esophagus.
In the stomach, alcohol increases acid secretion by stimulating gastrin secretion (a hormone that stimulates gastric acid secretion) and by stimulating the parietal cells themselves (stomach cells that secrete HCl). However, this stimulation only happens at concentrations of 5% and less and when the alcoholic beverages aren't distilled. Distilling concentrates the alcohol, making the beverage stronger. Higher alcohol content can delay gastric emptying, while low-alcohol content ca increase it. So it sounds like alcohol aids in digestion in the stomach only when the beverage has a low concentration.
In the intestines, alcohol can actually slow motility in alcoholics by affecting the mucosal layer and the vagus nerve. The vagus nerve connects the brain and the digestive tract.
In terms of digestion and absorption, alcohol can actually decrease the actions of enzymes that break down carbohydrates. And it can alter the absorption of several nutrients in patients with chronic alcohol abuse, such as vitamin B12, folic acid, thiamin, amino acids (leucine, phenylalanine, glycine, methionine, etc), calcium, and magnesium.
So it seems like if alcohol does in fact aid in digestion, it's only in moderation with beverages with low alcohol content. Typically, beers are going to be around 5% or less alcohol by volume (ABV). For instance, Miller Lite is 4.2% ABV and Yuengling is 4.4%.
Being a waste-case isn't good for anything and that includes your digestive tract. Any health benefits we see with moderate alcohol consumption are pretty much reversed when moderation becomes dependency. In fact, heavy drinking (5+ per day) is associated with increased risks for:
- high blood pressure
- stroke
- dementia
- some cancers
- central nervous system disorders
- vitamin and mineral deficiencies
Now, alcoholic drinks are not solely comprised of alcohol. There are other constituents like water, carbohydrates, phytochemicals like resveratrol and even antimicrobial compounds such as bismuth salicylate. I am well aware that these other things may change digestion and absorption, but there is only so much I can wrap my thoughts around at once.
Some resources I checked out:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2790779/?tool=pubmed
http://www.bmj.com/content/311/7021/1657.full#ref-5
http://fampra.oxfordjournals.org/content/25/6/445.full.pdf+html
http://ima.org.il/imaj/ar02mar-12.pdf
