When it comes to the harm of alcohol to health, I’m sure you can list three or two. Drinking alcohol may not only lead to liver cirrhosis, psychological problems, obesity and cardiovascular disease, but also closely related to a variety of cancers. A study in the lancet tells us that there is no so-called “safe dose” of alcohol intake: as long as you drink alcohol, the risk of cancer increases.
In addition to these health risks, alcohol can also cause permanent damage to the brain. In the existing studies, the relationship between alcoholism and brain injury has become increasingly clear: excessive alcohol intake is enough to change the structure of the brain, resulting in the reduction of gray matter and white matter in the whole brain, which may lead to cognitive impairment. However, the effect of relatively small amounts of alcohol on the brain is not clear.
Completely mistaken, if you think that moderate alcohol consumption (such as drinking a few bottles of beer or a bottle of Baijiu) a week is harmless to the brain. In a study published in nature communications, a team led by the University of Pennsylvania told us through a large-scale study that mild to moderate alcohol intake is also associated with the decline of brain volume. The harm of alcohol to brain health may be more serious and common than we expected.
There is often a problem in the research on this topic: the lack of large enough database. In this study, the authors used data from the UK Biobank. This data set contains genetic and medical information of 500000 middle-aged to elderly people. The study used some of this information, especially the MRI results of more than 36000 people, from which the volumes of gray matter and white matter in different brain regions can be calculated.
“The huge sample size we have allows us to detect subtle trends and even distinguish between the health risks caused by half a bottle of beer and one bottle of beer a day,” said Professor Gideon nave of the University of Pennsylvania, co-author of the paper, “This set of data is like a microscope or telescope with a stronger mirror. We have higher resolution and begin to observe unprecedented trends and correlations.”
To reveal the potential link between alcohol consumption and the brain, the key is to control countless variables and avoid making the relationship more mixed. To this end, they controlled for age, height, sexual behavior, smoking status, socio-economic status, genetic ancestry and other variables. In addition, they standardized brain volume data according to the age of participants.
The 36000 participants in biobank responded to their alcohol intake in the survey, ranging from not drinking at all to four alcohol units per day (one alcohol unit refers to 10 ml of alcohol, equivalent to about half a bottle of beer). When the researchers grouped participants according to how much they drank, they observed a sufficiently obvious trend: as alcohol consumption increased, the volume of gray matter and white matter in the brain decreased, and the change was not linear: the more they drank, the worse it would be.
The team noted that the changes in brain volume in these people were not concentrated in one brain region, but widespread throughout the brain, similar to those caused by aging. Therefore, the authors compared alcohol consumption with brain volume reduction caused by aging.
Specifically, for people in their 50s, if they change from never drinking to consuming an average of one alcohol unit a day, their brain is equivalent to aging by 0.5 years; From an average daily alcohol intake of one unit to two units, the brain is equivalent to aging by two years. With the increase of intake, the brain also shows a trend of accelerating aging: from 2 units to 3 units, which is equivalent to the aging of the brain by 3.5 years. In more extreme cases, never drinking alcohol to consuming four units a day is equivalent to aging the brain by more than 10 years.
“These findings contradict previous recommendations on safe alcohol intake,” said Professor Henry Kranzler, another corresponding author of the paper, “For example, the US Institute for the prevention of alcohol abuse and alcoholism previously recommended that women drink no more than one unit a day and men drink two units. In this study, this value has caused the brain to shrink.”
Using a large database, this study reveals the close relationship between drinking and the brain. For researchers, they also plan to further study the relationship between the two on the basis of this study. For example, advance the conclusion from correlation to causality, and reveal the effect of a single heavy drinking on the brain.
“This study focuses on average alcohol intake, but we also want to know how the brain will be different from drinking one glass of wine a day and not drinking at ordinary times but drinking seven cups in a short time on weekends. Some studies have pointed out that the latter is more harmful to the brain, but we haven’t studied it carefully.” Professor nave said.
reference material:
[1] Daviet， R。， Aydogan， G。， Jagannathan， K。 et al。 Associations between alcohol consumption and gray and white matter volumes in the UK Biobank。 Nat Commun （2022）。 https：//doi. org/10.1038/s41467-022-28735-5
[2] More alcohol， less brain： Penn-led study finds an association that begins with an average of just one drink a day。 Retrieved Mar 4 ， 2022 from https：//www.eurekalert. org/news-releases/945035
This article is from Wuxi apptec content wechat team