Carbohydrate Intake Linked to Vascular Brain Injury, Reduced Cognition

Elevated carbohydrate consumption is associated with vascular brain injury and reduced cognitive performance among middle-aged adults, according to findings published in EClinicalMedicine.

Researchers analyzed data from 9886 adults from Canada, Poland, India, and China to examine the relationship between macronutrient intake and magnetic resonance imaging (MRI)-detected markers of vascular brain injury and cognition. Participants had no history of cardiovascular disease or dementia. Their mean age was 58.1 years, 55.1% were women, 89.7% lived in urban settings, and 76.7% had completed postsecondary education. Macronutrient intake was assessed using country-specific food frequency questionnaires.

Participants in the highest third of carbohydrate intake had increased likelihood of covert brain infarcts (odds ratio [OR], 1.40; 95% CI, 1.11-1.78), high white matter hyperintensities (OR, 1.51; 95% CI, 1.20-1.89), and composite vascular brain injury (OR, 1.48; 95% CI, 1.24-1.75) compared with those in the lowest third. These individuals also scored lower on cognitive assessments, with reduced z-scores on the Montreal Cognitive Assessment (-0.059; 95% CI, -0.10 to -0.014) and the Digit Symbol Substitution Test (-0.044; 95% CI, -0.082 to -0.0056) compared with those in the lowest third.

In contrast, higher total fat intake was associated with lower prevalence of covert brain infarcts (OR, 0.75; 95% CI, 0.60-0.94) and composite vascular brain injury (OR, 0.77; 95% CI, 0.65-0.91). Monounsaturated fatty acids demonstrated consistent protective associations across all vascular injury markers and, along with polyunsaturated fatty acids, were associated with better Digit Symbol Substitution Test performance (0.054; 95% CI, 0.016-0.092) than those in the lowest third.

Study limitations include a cross-sectional design, potential dietary measurement error, and limited power to detect country-specific associations.

“Our results support the need for additional prospective observational studies or long-term and large prospective trials to assess whether macronutrient consumption can improve cognition and reduce incident vascular brain abnormalities, supporting the utility of dietary interventions as a potential pathway to prevent brain injury and cognitive decline,” the study authors concluded.

Disclosures: This research was supported by the Canadian Partnership Against Cancer, the Heart and Stroke Foundation of Canada, the Canadian Institutes of Health Research, and the Population Health Research Institute. Multiple study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures.