Does traditional asian vegetables ( ulam ) consumption correlate with brain activity using fMRI? A study among aging adults from low‐income households

BACKGROUND: Working memory and cognitive flexibility are supported by the dorsolateral prefrontal cortex (DLPFC). Aging adults from low-income households are individuals with a high risk of cognitive decline who incorporate ulam in their daily diet. PURPOSE: To examine relationship between ulam consumption and the working memory and cognitive flexibility among aging adults from low-income households who are more susceptible to cognitive decline. STUDY TYPE: Cross-sectional. POPULATION/SUBJECTS: Thirty-two aging adults (45-75 years old). FIELD STRENGTH/SEQUENCE: Task-based fMRI, 3.0T, T1 -weighted anatomical images, T2 *-weighted imaging data. ASSESSMENT: The dietary and ulam consumption were assessed using the respective validated Dietary History and semiquantitative Food Frequency questionnaires. Working memory and cognitive flexibility were evaluated by using neuropsychological batteries (ie, mini-mental state examination [MMSE], Digit Span, and Rey auditory verbal learning test [RAVLT]) and task-based fMRI (N-back and Stroop Color Word Test [SCWT]). Brodmann's areas 9 and 46 were the regions of interest (ROIs) of DLPFC activation. STATISTICAL TESTS: Multiple linear regression used to understand the relationship between ulam consumption and the working memory and cognitive flexibility, while analysis of covariance (ANCOVA) was used to compare the difference of working memory and cognitive flexibility among four percentiles of ulam consumption, after age, gender, and education years adjustments. Significance was decided by two-sided, P < 0.0042 and P < 0.05. RESULTS: The multiple linear regression revealed that ulam consumption was positively associated with the Digit Span (R(2) = 0.51, beta = 0.702, P < 0.001), right DLPFC activation (1-back) (R(2) = 0.34, beta = 0.591, P = 0.001), left DLPFC activation (SCWT-1) (R(2) = 0.33, beta = 0.553, P = 0.002), and left DLPFC activation (SCWT-2) (R(2) = 0.34, beta = 0.497, P = 0.004). The ulam consumption at the 75(th) and 100(th) percentile from the ANCOVA analysis had shown a better working memory and cognitive flexibility as compared with those of the 25(th) and 50(th) percentiles (P < 0.05). DATA CONCLUSION: This study found that high ulam consumption was related to a high intensity of brain activation in DLPFC; however, the elucidation of the neuroprotective properties of ulam have yet to be established from clinical trial studies. LEVEL OF EVIDENCE: 2 Technical Efficacy: Stage 4 J. Magn. Reson. Imaging 2020;51:1142-1153.