I can't seem to find a definitive answer as to whether alcohol increases insulin levels. I've seen some info that suggests alcohol raises your sugar level, and other info that suggests it lowers your sugar level, but nothing about insulin levels.
For this question, let's use 80 proof plain vodka as an example. Which, by definition, is 40% alcohol and 60% water (all other "impurities" are supposed to be filtered out of vodka--at least the top end stuff). This takes the question of the sugars in mixed drinks off the table.
So, if someone is drinking shots of 80 proof plain vodka, does it spike their insulin level?
With pubmed links...
Alcohol, insulin sensitivity and health:
Moderate alcohol consumption improves insulin sensitivity, lowers triglyceride concentrations and improves glycemic control. Not only in healthy folks, but also in type 2 diabetes. There is no clear consensus on the insulin sensitizing mechanism of alcohol, but one viable explanation may be that alcohol promotes leanness by stimulating AMPK in skeletal muscle. It's not a stretch to assume that this might have favorable effects on nutrient partitioning in the longer term.
If the effect of alcohol consumption on insulin sensitivity doesn't impress you, then consider the fact that studies have consistently shown that moderate drinkers live longer than non-drinkers. This can be mainly attributed to a lowered risk of cardiovascular disease. However, alcohol also contributes to a healthier and disease-free life by protecting against Alzheimer's disease, metabolic syndrome, rheumatoid arthritis, the common cold, different types of cancers, depression and many other Western diseases. The list goes on and on.
It can almost be said beyond doubt that moderate alcohol consumption is healthier than complete abstinence. With this in mind, it's strange that the fitness and health community shun alcohol. This irrational attitude seems to be grounded in the beliefs that alcohol is fattening and will hamper muscle gains. So let's take a look at that.
The sugar and carbs in alcholic drinks will spike insulin. However, as you proposed, we are only talking about "pure" alcohol.
I would be more concerned about alcohol lowering blood glucose levels -- especially for diabetics and those of us paleos that walk the VLC / LC line. It only happened to me once, but I ended a randomly VLC/high-protein+fat day with a bottle of wine. I won't say I almost died, but I certainly thought I might: extremely dizzy, nauseated, blurry vision, spots in vision, light headed ... and not in the fun, booze-type way.
Symptoms of hypoglycemia include dizziness, disorientation and sleepiness; however, these can also be side effects of drinking too much alcohol. This is why it's so important to actually check your glucose level, rather than rely on how you feel to tell whether your glucose levels are fine. Other symptoms include seizures, double or blurred vision, loss of consciousness, anxiety, sweating, hunger, tremor and heart palpitations. You may also experience confusion, or the inability to complete tasks that you would normally do.
I'm not diabetic, so this event really left an impression on me. I still enjoy a bottle of wine (ahem or two) every so often, but I make sure my diet that day gave me a good base to otherwise punish my body. Having a hypoglycemic event was definitely not a good time.
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