BOSTON, MA — Various studies suggest that moderate drinking helps prevent cardiovascular disease and lowers the risk for dementia. What hasn’t made the headlines are the downsides of alcohol for women. The July issue of Harvard Women’s Health Watch reports on the risks of alcohol, and why women, especially older women, are particularly vulnerable to them.

There is solid evidence for benefits from moderate drinking. For example, studies have shown that one drink per day, compared with no drinking at all, can reduce a woman’s risk for heart disease and stroke by as much as 50%. Other research suggests that older women who drink moderately have better cognitive skills.

But there are also risks. Even as little as one-half drink per day increases the risk for breast cancer, possibly because alcohol raises estrogen blood levels, which can promote the growth of breast tumors. Women are also quicker than men to become dependent on alcohol and to suffer the consequences, including damage to the brain and other organs, psychiatric problems, and accidents. One in 13 adults in the United States has a serious alcohol problem, and at least six million of them are women.

Women are more sensitive to alcohol than men are because their bodies contain less water and more fatty tissue. Water dilutes alcohol in the bloodstream; fat retains it. So women’s brains and other organs are exposed to higher concentrations of alcohol for longer periods of time. The risk increases with age.

Given the benefits and risks of alcohol, the Harvard Women’s Health Watch suggests that women 65 and over should be especially careful to limit themselves to one drink per day—or less.