MRI study links low-level drinking to brain changes

Low-level alcohol consumption may be associated with measurable brain changes on MRI, according to research published in Alcohol.

The study examined whether cumulative alcohol exposure was associated with regional cortical perfusion and cortical thickness in healthy adults who drank within commonly cited low-risk limits. Researchers modeled alcohol intake as a continuous exposure rather than placing participants into broad drinking categories.

Timothy C. Durazzo, PhD, of Stanford University School of Medicine, and colleagues studied healthy, nonsmoking adults with no history of alcohol use disorder or neurologic disease. Participants reported consuming fewer than 60 drinks per month during the year before the study.

MRI was used to measure regional brain perfusion and cortical structure. The perfusion analysis included 27 participants, while cortical volume and thickness analyses included 45 participants, according to a summary of the study.

The key finding was not simply that alcohol exposure alone correlated with brain measures. Rather, the interaction between age and total lifetime drinks was associated with lower cortical blood flow and thinner cortex. The strongest perfusion findings were reported in several cortical regions, particularly the frontal, parietal, and occipital lobes.

Similar structural patterns were observed in cortical thickness. Higher lifetime alcohol exposure combined with older age was associated with thinner cortex, especially in frontal and parietal regions, according to the study summary.

Those areas are relevant because frontal and parietal regions are involved in functions such as planning, attention, sensory processing, and emotional regulation. The findings suggest that even alcohol exposure within guideline-level ranges may not be biologically neutral for the aging brain.

“We did not expect the strength of the associations between greater number of drinks consumed over lifetime and higher age with decreased cortical blood flow to be as high as we observed,” Durazzo said.

The authors cautioned that the findings should be treated as preliminary. The sample size was modest, particularly for perfusion imaging, and the number of female participants was too small to assess sex-based differences. Other lifestyle factors, including diet and exercise, may also have influenced brain health.

The study does not prove that low-level drinking directly caused the MRI findings. However, it adds to research questioning whether current low-risk alcohol thresholds fully capture long-term brain effects.

Future work will need to test the findings in larger and more diverse cohorts. Durazzo said next steps include assessing whether low-level drinking is associated with balance, coordination, and dexterity.