No “safe limit”? Drinking changes young adults’ metabolite profile, research shows

29 Jun 2018 --- Adolescent drinking is associated with changes in the metabolite profile, a new study from the University of Eastern Finland and Kuopio University Hospital shows. Moreover, some of these changes were found to correlate with reduced brain grey matter volume, especially in young women who are heavy drinkers. The findings shed new light on the biological implications of adolescent drinking and could contribute to the development of new treatments.

“For instance, heavy-drinking adolescents showed increased concentrations of 1-methylhistamine, which, in turn, was associated with reduced brain grey matter volume,” researcher Noora Heikkinen from the University of Eastern Finland explains.

1-methylhistamine is formed in the brain from histamine produced by immune responses.

The researchers' findings suggest that the production of histamine is increased in the brains of heavy-drinking adolescents. 

“This observation can help in the development of methods that make it possible to detect adverse effects caused by alcohol at a very early stage. Possibly, it could also contribute to the development of new treatments to mitigate these adverse effects,” Heikkinen notes. 

The study was a 10-year follow-up study among adolescents living in eastern Finland. The researchers determined the metabolite profiles of heavy- and light-drinking young adults and used MRI to measure their brain grey matter volumes. These two methods have not been used in combination before, although previous studies have shown an association between heavy drinking and metabolite profile changes.

“What is new and significant about our study is the fact that we observed metabolite profile changes even in young people who consumed alcohol at a level that is socially acceptable. Moreover, none of the study participants had a diagnosis of alcohol dependence,” Heikkinen notes.

The findings indicate that even drinking that is not considered excessive has adverse effects on young people, both on their metabolism and brain grey matter volume, on the latter of which the research group has published findings already earlier.

“There is some evidence that the structural changes in the brain are reversible if the heavy drinking is not continued in the adulthood. However, if the heavy drinking continues for decades, it could cause problems with memory, learning and cognition, and could be seen as brain atrophy in MRI,” Heikkinen tells NutritionInsight.

“Although adolescent drinking is declining on average, we can see polarization: some adolescents are very heavy drinkers, and they also use other substances,” Heikkinen adds.

“The current so-called ‘safe limit’ for drinking (for those over 18 years) is 7 portions of alcohol for women and 14 portions for men in a week. One portion would be a small glass of wine or a small beer. The recommendation for underage persons is naturally not to drink alcohol at all. However, human brain develops well into the twenties, and it could be argued whether even alcohol use within these safe limits truly is safe for young adults,” Heikkinen puts forward.

Speaking about options for further research, Heikkinen says the researchers are currently planning a follow-up study, and part of it would be to redo the MRI scans and metabolite analyses to see if there are any further changes.