[...]another factor is simply genetics some people of different areas of the world make very little of the enzyme needed to break down the alcohol so unfortunetly they suffer double time.
Native Americans have only been exposed to alcohol for at best 400 years and for tribes, less than 200. This is not enough time to adapt to alcohol, and it's consumption in the presence of unlimited fresh water was far from a positive selection factor. So yes Native Americans produce very little (depending on flow of genes with European lineage) alcohol dehydrogenase. But if the negative effects you are referring to come after the positive effects have worn off, they do not suffer twice...actually the argument could be made that they actually suffer less, as the ratio of time drunk to time hung over is larger for those who do not metabolize alcohol and therefore stay drunk longer and get drunk on less...no if the suffering we are speaking of were addiction, then Native people suffers more.
And as for the causes of hangovers I assume you were agreeing with me as I used "constituents" instead of "congeners" which are the same thing, both jargon, one from chemistry, one from brewing/distilling/wine & mead making.
*edit: after rereading my other post I did not say that, I mentioned esters and phenols which are some of the common "congeners" in beer.
And I would argue that although darker beers are asociated with hangovers amomg beer geeks, and I would say not more than cheap yellow beer, that tannins are not the cause. Although red wine is full of tannins and is notorious for head splitting hangovers, grape juice is also full of tannins and causes no hangover like symptoms in even the youngest of those who abuse it. Again red wine is not fermented cold and is high in alcohol. The yeast that can survive these conditions (better than the bacteria) produce alcohols other than ethyl. Drink enough water and drink really good vodka...no hangover. You cannot drink enough water to not have a headache after a bottle or two of red wine. The same goes for beers of about 9% or more. Though the last two statements are merely opinion.
