Do all kinds of alcohol increase the risk of liver disease in a similar way? Or is an alcoholic beverage that is higher in alcohol by volume (e.g. scotch - ~60% and up) more harmful than those lower in alcohol by volume (e.g. red wine - 12%)?
The only difference it makes to the liver how alcohol is consumed is how high the blood alcohol content becomes and for how long - the other particulars of the beverage will be filtered out by the digestion process. Beverages containing a higher alcohol content will tend to cause a higher peak blood alcohol content because they can be consumed more quickly than the same amount of alcohol in a larger volume, and the more concentrated alcohol will be absorbed from the stomach more quickly. The liver is limited in its capacity to process alcohol. Low blood concentrations of alcohol are efficiently converted into acetate and metabolized, but at high concentrations some of the alcohol is converted into toxic acetaldehyde. Acetaldehyde is thought to cause hangover symptoms and also contribute to liver cell death through oxidative stress (Min, JA; Lee, K; Ki, D. June 2010. The application of minerals in managing alcohol hangover: a preliminary review. Current Drug Abuse Reviews, 3(2): 110-115). Replacement of these cells leads over time to enlargement of the liver, accumulation of scar tissue (cirrhosis) and cancer. So avoiding hangover by consuming alcohol in moderation may help avoid liver damage if alcohol is consumed. It is also very important to avoid consumption of acetaminophen with alcohol because processing the alcohol prevents the liver from properly eliminating the acetaminophen, which can cause severe liver damage.
Like the liver, the brain is also only concerned with the concentration of alcohol in the blood and how long it has been that way, in terms of how intoxication is experienced. It will take more alcohol as beer to produce the same level of intoxication as vodka because more of it will have had time to metabolize before the peak blood concentration is reached. The brain also becomes more tolerant to the effects of alcohol as time passes, so that the blood concentration has to be increased over time to maintain the same level of intoxication. So having more drinks to maintain the same experience will be harder on the liver than the initial drinks.
3" Low blood concentrations of alcohol are efficiently converted into acetate and excreted" ... this is incorrect. Acetate is never excreted. It enters the TCA cycle and is metabolized into CO2, water, and reduced nucleotides. It may also participate in de novo fatty acid synthesis. Jul 10, 2015 at 21:29
3"but at high concentrations some of the alcohol is converted into acetaldehyde which is toxic and may lead to liver cell death and replacement, " ... this is misleading. The mechanisms of hepatic toxicity from alcohol are complex. There is an important role of redox state change and gluathione depletion and a consequent inability to protect against oxidative stress. Jul 10, 2015 at 21:40
3"This "cell death" leads to the release of toxins from the cells which may contribute to the experience of hangover. " ... you'll need to provide a reference for this. The mechanisms of a "hangover" are complex but are not known to be related to hepatic cellular necrosis. Jul 10, 2015 at 21:42
1@scottb: Thank you for your helpful corrections. Jul 10, 2015 at 23:08
1I'm surprised that the methanol content is that high. I imagine the methanol content of scotch is higher than for wine because scotch is distilled, concentrating both the ethanol and the methanol. But I would still argue that this methanol is not toxicologically significant for a few reasons: At 0.1%, a liter of wine contains only 1 mL of methanol - less than the amount produced from metabolism of a kilo of apples (en.wikipedia.org/wiki/Methanol). Second, ethanol metabolism inhibits methanol metabolism (and is used as an antidote), making the methanol in these beverages less toxic. Jul 14, 2015 at 17:55