Much of the previous research on alcohol and health effects has relied on studies that can't prove cause and effect.
While it is known that excess drinking is harmful for health, a new study suggests that even consuming one or two alcoholic drinks a day can raise stroke risks, challenging previous claims.
Drinking alcohol moderately may not be as healthy as people or some researchers think.
The men on average drank four drinks a day and were at a far higher risk of suffering high blood pressure and strokes.
For the new study, the Chinese and British scientists took genetics into account.
He wrote in the report: "Stroke is a major cause of death and disability".
They say the findings are relevant to all populations and the best evidence yet on the direct effects of alcohol. Such can be used for the study of alcohol effects because this is not connected to other lifestyle choices such as smoking.
The scientists were able to study the impact of alcohol on people drawn from health, lifestyle and genetic data. She adds that their genetic investigations have paved the way for them to understand cause and effect relationships.
The researchers said Chinese formed the study group because of their distinct gene combination which reduces their alcohol tolerance level. At the start of the study, 33 percent of men and 2 percent of women reported drinking some alcohol, primarily spirits, on most weeks.
He said: "It is very roughly the opposite effect of taking a statin", which are drugs prescribed by doctors to help lower cholesterol levels in the blood and prevent heart attacks and strokes.
In more than 160,000 adult participants, the authors found two genetic variants that significantly lower alcohol consumption.
Harvard Health notes that strokes often aren't a surprise in the sense that many factors, only some genetic, increase one's odds of experiencing the potentially fatal issue.
"Risk of stroke increases proportionally with the amount of alcohol consumed, so if people do choose to drink, then they should limit their alcohol consumption". "Even moderate alcohol consumption increases the chances of having a stroke", said study co-author Zhengming Chen from the Nuffield Department of Population Health, University of Oxford in a press release. "I have always been reasonably convinced that moderate alcohol consumption was protective for cardiovascular disease, but now I am having my doubts", he said.
"This large collaborative study has shown that stroke rates are increased by alcohol", says Liming Li, coauthor and professor from Peking University.
Prof David Spiegelhalter, Winton professor for the public understanding of risk, at the University of Cambridge, said the study was making him waver.