Association of dietary pattern with cerebral blood flow and cognitive function

Abstract

Introduction: The inadequate blood supply to the brain is known predictive of cognitive decline. However, it remains unclear if diet patterns affect the cerebral blood flow (CBF) and contribute to cognitive impairment. This study aims to examine association between diet and CBF as well as cognition in an Asian population. Methods: The Neurological Biomarkers of Blood, MRI and Cognition study recruits Singaporeans aged 45-85 and collects their dietary habits using a 37-item diet screener. Dietary Approaches to Stop Hypertension (DASH) score (range 7-35) was calculated with a higher score indicating better compliance. Included food items were whole grain, vegetable, nuts and legumes, fruits, dairy, sugar-sweetened beverages, red and processed meat. Red and processed meat consumption was divided into levels one to four for amounts of above 0.71, (0.36, 0.71], (0.14, 0.36] and [0, 0.14] serving/day. Cognitive function was assessed using the Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA) and the scores were log-transformed. Participants showing signs of possible cognitive impairment underwent a 3T brain MRI scan, where the arterial spin labeling (ASL) technique was employed to measure CBF in both white and gray matter. After removing extreme values, CBF measurements are standardized by the intracranial brain volume and then Z-transformed by standard deviation. Results: The study included 243 participants, of whom 72 had ASL images. Participants had a mean (SD) CBF of 17.4 (8.7) and 34.2 (7.9) mL/100g/min in white and gray matter. After adjusting for age and gender, each 10-point increment in the DASH score showed non-significantly higher CBF in white matter (β = 0.18, 95%CI -0.34, 0.70) and gray matter (β=0.07, 95%CI -0.43, 0.58). Compared with the first level of meat intake, the second level was associated with higher CBF in gray matter (β = 0.61, 95%CI 0.03, 1.19) and higher log-MoCA (β = 0.45, 95%CI 0.07, 0.84). The third level of meat intake was associated with a higher CBF (β = 0.76, 95%CI 0.09, 1.44). Discussion: Optimal intake of red and processed meat but not overall DASH score was found to be associated with increased blood supply to brain as well as better cognitive performance.