In a recent Los Angeles Times op-ed piece, Reason contributor Stanton Peele notes that the pentennial argument about how to treat alcohol in the federal government's Dietary Guidelines for Americans has broken out once again this year as a panel of experts works on the 2010 edition. Opponents of acknowledging the health benefits of moderate drinking, as usual, worry that doing so will encourage excess. But the evidence of health benefits has become harder and harder to ignore, as reflected in the evolution of the government's advice:

1985: "One or two standard-size drinks daily appear to cause no harm in normal, healthy, nonpregnant adults."

1990: "Some studies have suggested that moderate drinking is linked to lower risk for heart attacks."

1995: "Current evidence suggests that moderate drinking is associated with a lower risk for coronary heart disease in some individuals."

2000: "Drinking in moderation may lower risk for coronary heart disease, mainly among men over age 45 and women over age 55."

2005: "The consumption of alcohol can have beneficial or harmful effects depending on the amount consumed, age, and other characteristics of the person consuming the alcohol, and specifics of the situation....Moderate alcohol consumption may have beneficial health effects in some individuals. In middle-aged and older adults, a daily intake of one to two alcoholic beverages per day is associated with the lowest all-cause mortality. More specifically, compared to nondrinkers, adults who consume one to two alcoholic beverages a day have a lower risk of coronary heart disease."

This year the the Dietary Guidelines Advisory Committee's report (the main basis for revising the guidelines) includes these findings:

Strong evidence consistently demonstrates that compared to non-drinkers, individuals who drink moderately have lower risk of coronary heart disease....

Moderate evidence suggests that compared to non-drinkers, individuals who drink moderately have a slower cognitive decline with age....

An average daily intake of one to two alcoholic beverages is associated with the lowest all-cause mortality and a low risk of diabetes and CHD among middle-aged and older adults.

In addition to acknowledging these associations, the committee proposes a more liberal definition of moderate drinking. The 2005 edition (like earlier editions) defined moderation as "the consumption of up to one drink a day for women and up to two drinks a day for men." In this year's advisory report, by contrast, "moderate alcohol consumption is defined as average daily consumption of up to one drink per day for women and up to two drinks per day for men" (emphasis added). The committee says this definition better fits the epidemiological evidence, which is based on questions about average daily, monthly, or yearly consumption. "Because most US citizens do not drink every day," it says, "the [committee] recommends that the definition for moderation be based on this general 'average' metric over the course of a week or month instead of an exact threshold of '1 drink per day for women or two drinks per day for men' each day." Still, the report cautions against cramming a whole week's drinking into a day or two, recommending that women consume "no more than three drinks in any single day" and that men have "no more than four drinks in any single day."

What the committee does not say is that subjects in epidemiological research (and surveys generally) probably tend to understate their alcohol consumption. If so, the levels of drinking associated with the best health outcomes may be higher than the data indicate, meaning that even the relatively generous standard recommended by the committee could be unnecessarily strict. In any case, as in all the previous editions of the guidelines, warnings about the hazards of drinking take up far more space than the few passages mentioning potential benefits. Given this overwhelmingly negative context, the concerns about encouraging excessive consumption seem overblown.

Back in 1996, Stanton Peele discussed alcohol and the dietary guidelines in  Reason.