Depending on who you ask, wine can either be a fountain of youth or a huge health concern, but as we know, the science behind wine and our health is seldom that cut and dry. A new study on alcohol's effects on the brain is a great example: Despite past research suggesting wine consumption can have positive effects on brain health, a paper published June 6 in the BMJ (formerly the British Medical Journal) found that even moderate drinking could have negative effects on our minds.
Using data from a 30-year study called Whitehall II, which tracked weekly alcohol intake and cognitive performance of British civil servants from 1985 to 2015, researchers from the University of Oxford and University College London measured the effects of different levels of alcohol consumption on brain structure and function. Of the 10,380-person study, 550 subjects were randomly selected for this sub-study, which assessed the subjects' performances in language fluency and short-term memory recall tests. Participants also underwent an MRI scan to measure hippocampal atrophy (shrinkage of a part of the brain important for memory, which is commonly found in patients suffering from Alzheimer’s disease), white matter microstructure (essential for processing thoughts quickly) and grey matter density.
Ultimately, the study found that the more a participant drank, the more their brain changed over time. Odds of hippocampal atrophy, poorer white matter tracts and a decline in language fluency were shown to be higher for drinkers (even moderate ones) than non-drinkers. Even light drinking showed no protective effects compared to abstinence.
"We were surprised not to find a protective effect of moderate drinking, because a number of previous studies have reported one," Anya Topiwala, the study's co-author, told Wine Spectator in an email. "I think this may be because of limitations in the methods of these studies, for example not taking full account of characteristics of moderate drinkers, such as higher IQ, which would predict better memory test performance and may mask damage done by alcohol."
This study has limitations, too, however. One of the caveats listed in the report—and one of the most common limitations of most observational studies on this subject—was that the data on alcohol use was self-reported. Often, there is a chance that participants may under-report their alcohol use, sometimes even unintentionally. Other lifestyle factors can play a role, as well.
Also, because of the selection criteria, the chosen subjects were a rather small group, which meant it didn’t represent the larger, diverse study population. As the study text notes, "There was a higher proportion of men, and participants were slightly less educated, with higher blood pressure and lower measures of depressive symptoms compared with the larger Whitehall II cohort."
Regardless, as Topiwala explains: "We need to keep in mind this is just one study and we need further research to definitively answer whether drinking at lower levels is bad for brain health."
And just as one study suggests that alcohol might be bad for the brain, another recently published report backs up the idea that red wine protects against neuro-degenerative diseases such as Alzheimer's and Parkinson's. Researchers from the Institute of Food Science Research in Madrid, the University of Reading in the United Kingdom and the University of Illinois tested the protective mechanisms of wine-derived human gut metabolites (red-wine compounds left behind in the body after digestion) on brain cells affected by stress conditions related to neuro-degenerative disease.
The study, published in the online journal Frontiers in Nutrition, showed that the metabolites were effective in protecting the brain cells from dysfunction and death, which typically occur under these stress conditions. The report also notes that the metabolites were active at different times during the study, signifying that the exact makeup of these metabolites can affect their individual functions.
Due to the complex community of microorganisms that exist in our digestive tracts, wine can be broken down in different ways, resulting in different types of metabolites. Further studies are needed in order to determine which gut conditions can maximize this health benefit, but it appears healthy eating is key.
The bottom line is that these reports just scratch the surface of the complicated relationship between wine and the brain. We still have a lot to learn.