A dizzying array of research suggests alcohol can have both good and bad effects, but making sense of such studies all comes down to who you are and how much you drink.

That point was driven across Tuesday with the release of a U.S. study suggesting women who consume three to six alcoholic beverages a week face a small increased risk of breast cancer, but it's not enough of a danger to stop drinking. The study in the Journal of the American Medical Association involved 105,986 nurses who were tracked for three decades.

The Canadian Public Health Association (CPHA) concludes that while studies have shown alcohol has some health benefits, their scope is limited. In effect, the harmful effects of alcohol "on the body as well as on society far outweigh the good."

The Ottawa-based association stresses that women are particularly vulnerable to the harmful effects of alcohol, for various reasons: their generally lower body weight and less water in the body compared with men means they can't safely drink the same amount, and drinking during pregnancy and while breastfeeding can harm the fetus or baby.

Research also suggests that underage drinking can lead to problem alcohol use in adulthood, according to the U.S. National Institute on Alcohol Abuse and Alcoholism.

The CPHA says there's nothing wrong with "kicking back with a cool one after a long day." However, "it’s what happens after more than one drink that is troubling."

The World Health Organization, for instance, says alcohol-related injuries are a growing public health concern, with injuries such as road traffic accidents, burns, poisonings, falls and drownings making up more than a third of the disease burden attributed to drinking. The WHO, which says Thailand will host a Global Alcohol Policy Conference from Nov. 28-30, says 2.5 million people die annually from harmful use of alcohol.

Drinking for health not a good idea

Despite studies showing some alcohol-related health benefits, "alcohol shouldn’t be considered a health measure," the CPHA warns, noting that healthy eating and exercise are better choices.

That said, following are some recent studies suggesting alcohol is:

- Brain power (August 2011): Chicago researchers conducted a Neuropsychiatric Disease and Treatment review of more than 140 studies since 1977 that included 365,000 people, and found moderate drinkers (one drink a day for women, two drinks a day for men) have a 23 per cent reduced risk of developing Alzheimer's disease, other kinds of dementia and cognitive impairment.

- Stronger bones (February 2010): California researchers say growing research suggests beer may have nutritional properties. Some brands contain silicon, a nutrient that helps strengthen bones and might help reduce the risk of osteoporosis and other diseases including heart disease. "The reality is there's now growing consensus around the world that the active ingredient in alcoholic beverages that counters atherosclerosis is alcohol. It doesn't matter if it's wine or beer," said Charles Bamforth, a biochemist at the University of California, Davis.

- Healthier heart (November 2010): Researchers at Toulouse University in France find that regular and moderate alchohol intake through the week is associated with low risk of ischemic heart disease, but binge drinking results in a higher risk. The study examined 9,758 men in three cities in France and Belfast in Northern Ireland who were free of heart disease when the research began in 1991, and followed them over an average of 10 years.

- Lower dementia risk (July 2009): A Wake Forest University study presented at the International Conference on Alzheimer's Disease suggests a glass or two of alcohol daily offers long-term cognitive protection and reduces the risk of dementia in older adults with no memory problems, offers long-term cognitive protection and reduces the risk of dementia in older adults. The study involved 3,069 individuals 75 years or older who drank beer, wine and liquor.

- Sleep problems (August 2011): A Japanese study in Alcoholism: Clinical & Experimental Research suggests alcohol may help young men fall asleep, but could interfere in keeping them asleep. The study looked at 10 healthy men around 22 years old who were given a drink 100 minutes before hitting the sack.

- Birth problems (July 2011): Toronto and other researchers report in the International Journal of Obstetrics and Gynaecology that heavy alcohol consumption during pregnancy increases the risk of low birth weight, pre-term birth and other complications. The more heavily a pregnant woman drank each day, the higher the risk of those complications, according to the report that reviewed 36 previous studies.

- Cancer risk (October 2009): Chicago researchers, reporting in Alcoholism: Clinical and Experimental Research, find alcohol stimulates "epithelial-to-mesenchymal transition," in which run-of-the-mill cancer cells morph into a more aggressive form and begin to spread throughout the body.

- Bone problems (October 2008): A Loyola University Stritch School of Medicine study suggests binge drinking disturbs genes necessary for maintaining healthy bones. The study on rats follows numerous studies that have demonstrated that binge drinking can decrease bone mass and bone strength.

- Fetal alcohol (September 2007): University of Manitoba researchers find more children are born with fetal alcohol spectrum disorder, and call for governments to increase support for the ones who are ending up in foster care. The report says children with the disorder are generally taken from their families at a younger age and more likely to spend the remainder of their youth in care than other foster children.