The controversy relates to the question of moderate drinking as a lifestyle “marker” for a range of healthy behaviors. In other words, people in this group –as opposed to heavy drinkers or nondrinkers – tend to exercise more, be better integrated socially, less likely to be depressed, and have a higher level of education. If this is the case, so goes the reasoning, the alcohol has little to do with the health benefits. But the pattern held up even after these other factors, known as confounding variables, were accounted for in the statistical analysis.
In any case, what is clear is that moderate drinking in old age is associated with both measureable reduction in the odds of mental decline and the healthy lifestyle factors that are likely to also contribute. Independent data from other studies verifies that wine drinkers enjoy a higher quality of life in old age. My take on it is that there are synergies between living the good life and moderate drinking, much as the polyphenol molecules in wine seem to have the best effects in combination and with alcohol.
What is confounding to me is why we are still so conflicted on the question. It’s not like we are talking about keggers at the nursing home, just a glass or two of wine with dinner.
More info at AIM.