The study found that drinking between 100-200 grams of alcohol could decrease one's life expectancy by six months, 200-350 grams by two years and more than 350 grams by four years. But drinking above 100 grams a week also kicked off much higher risk of stroke, heart failure, fatal aortic aneurysm, and disease from high blood pressure that could cancel out the benefits from lower heart attack risks.
The findings support recently lowered guidelines in the United Kingdom, which suggest there is no safe level and recommend that both men and women's drinking should not exceed 14 units a week.
"When the U.S. reviews their guidelines, I would hope they would use this as evidence to consider lowering the guidelines for men probably in line with female guidelines", the study's lead author, Angela Wood, a senior lecturer at the University of Cambridge, told The Washington Post.
To get there, they analyzed 83 studies on alcohol consumption pulled from a variety of worldwide studies spanning nearly 50 years and 19 countries, allowing them to compare the effects on multiple different "subtypes in current drinkers of alcohol".
The maximum safe limit was nearly 5 drinks per week - that meant 100g of pure alcohol, or 5 pints of 4% ABV beer, or five glasses of 13% ABV wine that measures 175ml each.
Current Irish guidelines recommend a limit of 170g pure alcohol (17 standard drinks) per week for men and 110g pure alcohol (11 standard drinks) for women. This equates to around six pints of beer or six glasses of wine a week.
The team also explored links between how much alcohol people consumed and their risk of different types of cardiovascular disease. However, risk of non-fatal heart attacks dipped with more alcohol.
The more people drank, the higher the risk of a range of life threatening illnesses, including stroke and heart failure.
"This is a serious wakeup call for many countries", said Jeremy Pearson, associate medical director at the British Heart Foundation charity, which helped fund the study, in a statement.
The study, which looked at data from 600,000 people in 19 countries, supported the UK's low safe-drinking limits. Public health advocates have criticized the Moderate Alcohol and Cardiovascular Health (MACH15) study in part because starting in 2013, the National Institute on Alcohol Abuse and Alcoholism solicited donations from the world's biggest alcohol producers, according to the New York Times, to fund the $100 million study-a project equal to a quarter of the agency's annual budget. Above this, there was increased risk of both heart attack and heart disease.
The study's likely to be controversial, said Jason Connor and Wayne Hall of the University of Queensland Centre for Youth Substance Abuse Research in Australia.
The researcher found that those people who drink about five glasses of wine a week or more may have the higher risk of early death.
"We should always remember that alcohol guidelines should act as a limit, not a target".
About half of the people included in the study said they had more than 100 grams of alcohol per week.