Learning! What's the deal with hangovers?

It's always fun to find out about everyday things that scientists still can't really explain.  One of these things is the ubiquitous hangover.

Now, chances are you're already mentally correcting me: "no, Andrea, hangovers are not a mystery - they are caused by dehydration!"  If you are more caught up with the research, you may have replaced dehydration with acetaldehyde, a byproduct our bodies create when they process alcohol.

Well, you'd both be sort of, maybe, kind of, probably right.

The current, most favourite theory is the acetaldehyde theory.  When our bodies process alcohol, the first byproduct is acetaldehyde, a compound more toxic than alcohol itself that causes things like nausea, vomiting, and the sweats.

Other theories include the famous dehydration theory as well as an imbalance of the enzymes NAD+ and NADH.  NADH is used to process alcohol, and when our bodies convert NAD+ into NADH for such a purpose, our cells lose some of their functioning.

Sadly, both the dehydration and enzyme theories have been shown insufficient in studies.

One more promising theory is that it's an immune response, and that our bodies are producing excess cytokines in response to the alcohol we have consumed.  Since cytokines are used to fight infection by producing inflammatory responses, they could very well be making us feel like junk after a night of drinking.

Of course, this doesn't help us prevent hangovers, unless you avoid setting off all these poison-responses in your body by just not drinking at all.

Source: Smithsonian Mag