Abstract
OBJECTIVES: There is emerging evidence linking fruit and vegetable consumption and cognitive function. However, mechanistic evidence underlying this relationship is lacking. We aim to examine the association between plasma carotenoids and cognition in a population at risk for cognitive decline. METHODS: The Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) trial (R01 AG052583) is an ongoing randomized controlled intervention on the effects of the MIND diet in preventing cognitive decline. The primary outcome is global cognition assessed using a battery of 12 cognitive tests. Plasma carotenoid levels were measured in 295 participants. Multivariate linear regression models were used to examine the association between blood nutrients and global and domain-specific cognition. Model was adjusted for age, sex, education, study site, smoking status, and frequency of cognitive and physical activities. The Benjamini-Hochberg method with a false discovery rate of 0.25 was used for multiple testing. RESULTS: Participants are predominantly Caucasian females (68%) with obesity (BMI 33.6) and a mean age of 69.8 years. High plasma α-carotene was associated with higher average scores for a global measure of cognition. Individuals in the highest tertile of plasma α-carotene levels (tertile median: 155.8 mcg/L) had a higher average score of 0.17 for global cognition compared to those in the lowest tertile (tertile median: 34.9 mcg/L, P = 0.002). Individuals with high plasma α-carotene levels had a dietary pattern that featured high consumption of vegetables other than green leafy vegetables (i.e., carrots, corn, beets, green beans, and onions), and fruits, as well as, lower consumption of butter, margarine, and fried foods. Plasma levels of α-carotene (p for trend 0.007) and lutein plus zeaxanthin (p for trend 0.009) were also associated with higher mean scores for semantic memory. CONCLUSIONS: Higher circulating levels of specific forms of carotenoids i.e., α-carotene, lutein plus zeaxanthin was associated with higher scores of global and domain-specific cognitive function in a US population at risk for cognitive decline. FUNDING SOURCES: Funding: R01 AG052583