What Is Moderate Drinking?

Alcohol Research & Health, Wntr, 1999 by Mary C. Dufour

Defining "Drinks" and Drinking Levels

As documented by ancient texts, people have long been aware of both the harmful and beneficial effects of drinking alcohol. Research into alcohol's effects, however, is relatively new, as evidenced by the fact that the National Institute on Alcohol Abuse and Alcoholism (NIAAA) was not created until 1971. Initially, alcohol researchers focused primarily on understanding alcoholism and on identifying effective prevention and treatment strategies. In recent years, however, moderate drinking also has become a topic of great interest and lively debate as researchers and the media have reported on the health benefits of moderate alcohol consumption. For example, studies have indicated that moderate drinking may be associated with reduced risk of heart attack, atherosclerosis, and certain types of strokes as well as a reduced risk of brittle bones (i.e., osteoporosis) in postmenopausal women.

To discuss adequately the potential benefits and risks associated with moderate drinking, one must first answer the question, What is moderate drinking? The meaning of the term "moderate" is highly subjective, however, and what one person considers to be moderate drinking, another person may view as heavy drinking. This variability makes it difficult to compare or interpret study findings regarding the consequences of moderate drinking. Accordingly, a definition of the terminology "moderate drinking" is needed to allow an informed discussion of the risks and benefits associated with such a drinking pattern.

Many current definitions of moderate drinking are based on a specific number of drinks consumed during a designated time period (e.g., per day or per week). This definition, however, raises the obvious question, What is a "drink"? Another important question is, Why does it matter how a drink is defined? This article first reviews considerations relevant to defining a drink. It then describes several approaches to determining people's drinking levels and patterns. Finally, based on that information, the article presents definitions of moderate drinking that are currently used in the United States and in other countries.

WHAT IS A DRINK?

Both the definition and standardization of the term "drink" are relevant primarily in two settings: (1) commercial establishments that serve alcohol (e.g., restaurants and bars) and (2) alcohol research. The standardization of drink sizes has been a long-standing practice in alcohol-serving establishments. Commercial measures of alcoholic beverages, however, are heavily influenced by local drinking customs and regulations. In some countries, the serving sizes for various alcoholic beverages are mandated by law and, consequently, are uniform from one establishment to another. In the United States, however, each bar, restaurant, or other establishment that serves alcoholic beverages can set its own standards, although establishments generally are consistent in the sizes of the drinks they serve.

In private homes, drink sizes may vary even further. For beer, wine coolers, and similar alcoholic beverages, the serving size is most likely to be consistent across different households because a "serving" or drink often corresponds to one (standard size) can or bottle. For wine and distilled spirits (e.g., vodka and whiskey), however, the size of one drink is entirely up to the person pouring it and may vary from occasion to occasion.

Surprisingly, even in alcohol research no universally accepted standard-drink definition exists, although such a definition would be helpful for comparing the results of different studies. The lack of a definition is, to some extent, historically based. When alcohol-use surveys of the general population were first instituted, they focused primarily on the distinction between drinkers and nondrinkers (Clark and Midanik 1982). For example, in 1939 the Gallup surveys, which probably were the first surveys to measure drinking on a national level in the United States, included the following question regarding alcohol consumption: "Do you have the occasion to use alcoholic beverages such as liquor, wine, or beer, or are you a total abstainer?" (Clark and Midanik 1982).

As alcohol survey research progressed and investigators became interested in assessing the consequences of various levels and patterns of alcohol consumption, scientists had to develop methods to quantify consumption more accurately. Over the 50 years that alcohol researchers in the United States and abroad have conducted surveys of alcohol consumption and alcohol-related problems in representative population samples, investigators have made great progress in survey research methodology, including the quantification of drinking levels. Nevertheless, no consensus currently exists as to the best methods or questions for eliciting reliable information on how much alcohol respondents drink. (Various currently used approaches for assessing drinking levels and patterns, as well as their advantages and disadvantages, are discussed in the section "Assessing Alcohol Consumption.")