Have you ever heard that drinking a glass of wine a day can make good health? The study published in the scientific journal The Lancet disputes these other theories that the consumption of moderate amounts can protect the body from some diseases.
Research conducted by experts from the UK and China who have been tracked by 500,000 Chinese adults over the age of 10 points out that even moderate alcohol intake can increase blood pressure and stroke risk, a popular stroke.
According to scientists, conclusions are by now the safest evidence of the direct action of alcohol on the body and valid for every society on the planet.
However, researchers with whom the BBC spoke and who did not participate in the study made reservations.
It is well known that over-consumption of alcoholic beverages is harmful to health and increases the risk of stroke. Some studies, however, claim that small quantities of swine can make a good body, while others claim that there is no safe alcohol consumption level.
Increased risk of stroke
Researchers linked to the Oxford University, the Beijing University and the Chinese Academy of Medical Sciences have found that one or two doses a day increase the risk of stroke by 10-15%, which would jump to about 35% at four doses per day.
The dose is defined as a glass of wine or beer bottle or standard distillate measure.
The World Health Organization estimates that 2.3 billion people worldwide consume alcoholic beverages, averaging 33g a day, which is about two bottles of 150ml wine, a 750ml beer bottle. or two doses of 40 ml of distillate.
The study found no indication that alcohol consumption, albeit in a reduced form, had a "protective" effect.
"The claims that wine and beer have magical protective effects are not being retained," said Richard Peto, co-author of the study and professor of medical statistics and epidemiology at Oxford University.
At the link between risk of heart attack and alcohol consumption, the researchers said the data was unconvincing and that further analysis was needed.
The analysis focused on the Asian country because a significant percentage of the population in that region has genetic variants that limit their tolerance to alcohol.
Since its genetic makeup has a major influence on drinking, but not on other variables, such as nutrition and tobacco consumption, scientists can use it as a parameter to determine the consequences of alcohol intake.
Researchers point out that by comparing the results of alcohol-consuming and retarded Chinese genetic testing, they were able to pinpoint the direct effects of alcohol at risk of stroke.
"Using genetics is a new way to clarify whether moderate drinking is actually protecting us or harming us," said Ion Millwood of Oxford University, a co-author of studies and an expert on epidemiology.
"Genetic analysis has helped us understand the cause-and-effect relationships."
For researchers, the main message of the paper is that no level of alcohol consumption protects us from stroke – that is, even drinking a small amount increases the chance of stroke – and that, therefore, the consumption of beverages to a minimum.
What do other experts say?
The study has caused some doubts in the scientific community. Stephen Burgess from Cambridge University said the analysis had some limitations, including the fact that it focused only on the Chinese population and focused on consumption of distillates and beer, but not wine.
However, the expert has confirmed that the results reflect the long-term research of the scientific community about the effect of alcohol consumption on the body.
"He strongly emphasizes that there is no cardiovascular benefit in moderate intake and that the risk of stroke increases even with reduced consumption of beverages."
"The risk of stroke increases in the same proportion as the amount of alcohol consumed, so if a person decides to drink, they should limit their consumption."
For Kevin McConway, the emeritus professor of applied statistics at the British Open University, the research does not answer "all" questions.
"It increases what we know about the role of alcohol in certain diseases, but this may not be the last word," he said.
"It does not explain how exact alcohol increases the risk of stroke, but not the heart attack."
In any case, emphasizes David Spiegelhalter, a professor of Public Understanding Discipline at the University of Cambridge, the study has helped to relativize theories that had long been widely accepted.
"I've always been reasonably convinced that moderate alcohol consumption has been protected from cardiovascular disease, but now I have my doubts."