Is alcohol a tonic or a toxin? The question is especially critical to older people, whose overall medical picture gives alcohol the potential to be a health benefit or a life-shortening hazard.

Yet experts say that doctors rarely ask older patients how much and how often they drink. Not knowing the answers to these questions can result in misdiagnosis, medical complications and life-threatening accidents. Doctors may also fail to recognize the symptoms of alcohol abuse, a problem that is expected to become increasingly common as baby boomers, who have been found to drink more than previous generations, reach age 65 and beyond.

At the same time, older people who are in good health should know that moderate drinking under the right conditions may improve their health in several important ways. In a comprehensive review in the October issue of The Journal of the American Dietetic Association, Maria Pontes Ferreira and M. K. Suzy Weems described the myriad health benefits and risks of alcohol consumption by aging adults.

In summarizing the findings in an interview, Dr. Ferreira, a registered dietitian, said that “although there are a lot of benefits from moderate alcohol consumption, you can’t make a blanket statement; you have to look at the big picture.”

“Moderate alcohol consumption can improve appetite and nutrition and reduce the risk of several important diseases, including cardiovascular diseases and diabetes,” said Dr. Ferreira, a postdoctoral fellow at Haskell Indian Nations University in Lawrence, Kan. “But a lot of folks over 50 are already dealing with diseases associated with aging and medication use that can result in possible complications and drug interactions. And older people who abuse alcohol are consuming an inordinate amount of calories that can displace important nutrients.”

Furthermore, Dr. Frederick C. Blow, professor of psychiatry at the University of Michigan Medical School and an expert on alcohol and aging, pointed out in an interview that “even at lower levels of consumption, alcohol can be problematic for older people.”

“Because of an increased sensitivity to alcohol and decreased tolerance as one ages, lower amounts of alcohol can have a bigger effect,” he said. “Older people get into trouble with doses of alcohol that wouldn’t be a problem with a younger person.”

Madeline A. Naegle, professor at the New York University College of Nursing, fears that publicity about the benefits of alcohol has dangerously tipped the scales, prompting some people to think that “if one drink is good, two or three must be better.”

“Recommendations about drinking must be qualified by the level of a person’s health,” she emphasized in an interview.

In an article on screening for alcohol use and abuse among older adults in the November issue of The American Journal of Nursing, she noted: “Often clinicians fail to ask, ‘Do you drink alcohol?’ when obtaining medical histories and performing routine examinations. Because alcohol consumption is such a common practice, questions about drinking are necessarily part of a general health assessment.”

The Benefits

Evidence for the benefits of moderate alcohol consumption comes almost entirely from epidemiological, or population, studies that can reveal important associations but cannot prove cause and effect. There have been few randomized controlled clinical trials of alcohol use to definitively show that alcohol consumed in any amount by any group of people benefits health.

That said, here is what the studies indicate. It’s important to note that most findings refer to moderate consumption, defined as one alcoholic drink a day for women and up to two for men. Also, the benefits are confined to people who do not have ailments, like chronic liver disease, or take medications, like psychoactive drugs, that would render any amount of alcohol risky.

Heart disease and mortality. While many studies have emphasized the benefits of red wine to cardiovascular health and longevity, more than 100 studies in 25 countries have linked these benefits to moderate consumption of any type of alcoholic beverage. On average, moderate drinkers 50 and older are less likely to suffer heart attacks and die prematurely than abstainers and heavy drinkers.

Diabetes. Though it may seem counterintuitive, a controlled clinical trial of nondiabetic older women found that insulin sensitivity was improved among those who consumed two drinks a day.

In studies of men with diabetes, drinking up to two drinks a day was associated with lower levels of factors linked to an increased risk of heart disease, like markers of inflammation and arterial dysfunction.

Dementia. Although excessive alcohol drinking can raise the risk of dementia in older people, “there are emerging data to suggest that moderate alcohol intake — one to three drinks a day — is associated with a reduced risk of developing Alzheimer’s disease and vascular dementia,” Dr. Ferreira and Dr. Weems wrote. In this case, they added, drinking wine confers the primary benefit; drinking beer, on the other hand, appears to raise the risk of dementia.

Osteoporosis. Several studies have suggested that elderly women who drink moderately tend to have better bone density. But chronic heavy drinking “can dramatically compromise bone quality and may increase osteoporosis risk,” H. Wayne Sampson of Texas A & M University Health Science Center in College Station has reported for the National Institute on Alcohol Abuse and Alcoholism. Furthermore, skeletal damage from excessive drinking is not reversible.

Psychosocial effects. Although there is relatively little research on the effects of moderate alcohol consumption on mental and social well-being among the elderly, studies in retirement communities have noted an improvement in social interactions, health-related quality of life and survival.