Flavonol Intake and Cognitive Decline in Middle-Aged Adults

Abstract

Cognitive decline occurs with age and may be slowed by dietary measures, including increased intake of dietary phytochemicals. However, evidence from large and long-term studies of flavonol intake is limited. Dietary intakes of flavonols were assessed from a large biracial study of 10,041 subjects, aged 45-64, by analysis of a food frequency questionnaire administered at visit 1 of triennial visits. Cognitive function was assessed at visits 2 and 4 with the following three cognitive performance tests: the delayed word recall test, the revised Wechsler Adult Intelligence Scale digit symbol subtest, and the word fluency test of the Multilingual Aphasia Examination. The change in each score over 6 years was calculated, and a combined standardized change score was calculated. Generalized linear models controlled for age, ethnicity, gender, education level, energy intake, current smoking, physical activity, body mass index, diabetes, and vitamin C intake. Total flavonols across quintiles of intake were positively associated with preserved combined cognitive function (P<.001). This pattern with preserved combined cognitive function was consistent for the three major individual flavonols in the diet, myricetin, kaempferol, and quercetin (each P<.001). The positive association with total flavonols was strongest for the digit symbol subtest (P<.001). In this cohort, flavonol intake was correlated with protected cognitive function over time.

The protective effects of polyphenols on Alzheimer's disease: A systematic review

“…Similarly, Root et al. [32] reported that flavonols intake was associated with preserved cognitive function ( P < .001). A study by Butchart et al.…”

“…The biomarkers included are Aβ40 and Aβ42 accumulations, presence of APOEɛ4 genotype, brain volume, tHcy levels, cerebral blood flow, oxidative stress levels, dental gyrus function, aldehydes malondialdehyde levels [22–28]. Sixteen studies assessed changes in cognition with the use of different cognitive tests, depending on the specific cognitive outcome measured [22,25,29–41]. More information on this is available in the data extraction tables in Appendix D.…”

“…More information on this is available in the data extraction tables in Appendix D. To assess dietary intake, five of six observational studies used either Frequency Food Questionnaire or Semi‐quantative Frequency Food Questionnaire [29–33]. One study used 24‐hour dietary record [34], and one study also carried home interviews besides the questionnaires [30].…”

“…The biomarkers included are Ab40 and Ab42 accumulations, presence of APOE 34 genotype, brain volume, tHcy levels, cerebral blood flow, oxidative stress levels, dental gyrus function, aldehydes malondialdehyde levels [22][23][24][25][26][27][28]. Sixteen studies assessed changes in cognition with the use of different cognitive tests, depending on the specific cognitive outcome measured [22,25,[29][30][31][32][33][34][35][36][37][38][39][40][41]. More information on this is available in the data extraction tables in Appendix D. To assess dietary intake, five of six observational studies used either Frequency Food Questionnaire or Semi-quantative Frequency Food Questionnaire [29][30][31][32][33].…”

“…Sixteen studies assessed changes in cognition with the use of different cognitive tests, depending on the specific cognitive outcome measured [22,25,[29][30][31][32][33][34][35][36][37][38][39][40][41]. More information on this is available in the data extraction tables in Appendix D. To assess dietary intake, five of six observational studies used either Frequency Food Questionnaire or Semi-quantative Frequency Food Questionnaire [29][30][31][32][33]. One study used 24hour dietary record [34], and one study also carried home interviews besides the questionnaires [30].…”