Their study included over 1,800 people, aged 55 to 65 when the study began. Sixty-nine percent of the participants were men. The subjects were followed for 20 years.
Surprisingly, the group with the lowest mortality rate was moderate drinkers, who had one to three alcoholic drinks per day, followed by heavy drinkers, and then light drinkers, while non-drinkers had the highest mortality rate of them all.
Part of the theory as to why this is so has to do with the modern increase in methanol in food (and cigs), and the physiology by which ethanol helps us to process methanol. Methanol (wood alcohol) is a toxin. Mercola (the first source) offers a good rundown on a variety of possible factors, as well as some warranted warnings about the risks involved in alcohol consumption. Also it is worth noting here that the majority of study participants were male, and females have considerably more difficulty metabolizing ethanol.
Med Hypotheses. 2010 Mar;74(3):493-6. Epub 2009 Nov 5.
Methanol: a chemical Trojan horse as the root of the inscrutable U.
Arizona State University (retired), 470 South Rainbow Drive, Page, Arizona 86040, United States. email@example.com
Until 200 years ago, methanol was an extremely rare component of the human diet and is still rarely consumed in contemporary hunter and gatherer cultures. With the invention of canning in the 1800s, canned and bottled fruits and vegetables, whose methanol content greatly exceeds that of their fresh counterparts, became far more prevalent. The recent dietary introduction of aspartame, an artificial sweetener 11% methanol by weight, has also greatly increased methanol consumption. Moreover, methanol is a major component of cigarette smoke, known to be a causative agent of many diseases of civilization (DOC). Conversion to formaldehyde in organs other than the liver is the principal means by which methanol may cause disease. The known sites of class I alcohol dehydrogenase (ADH I), the only human enzyme capable of metabolizing methanol to formaldehyde, correspond to the sites of origin for many DOC. Variability in sensitivity to exogenous methanol consumption may be accounted for in part by the presence of aldehyde dehydrogenase sufficient to reduce the toxic effect of formaldehyde production in tissue through its conversion to the much less toxic formic acid. The consumption of small amounts of ethanol, which acts as a competitive inhibitor of methanol's conversion to formaldehyde by ADH I, may afford some individuals protection from DOC.
PMID: 19896282 [PubMed - indexed for MEDLINE]