Flavonoid intake and MRI markers of brain health in the Framingham Offspring Cohort

Authors: SHISHTAR, ESRA - Tufts University; ROGERS, GAIL - Jean Mayer Human Nutrition Research Center On Aging At Tufts University; BLUMBERG, JEFFREY - Tufts University; AU, RHODA - Boston University; DECARLI, CHARLES - University Of California; JACQUES, PAUL - Jean Mayer Human Nutrition Research Center On Aging At Tufts University

Submitted to: Journal of Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/28/2020
Publication Date: 3/25/2020
Citation: Shishtar, E., Rogers, G.T., Blumberg, J.B., Au, R., DeCarli, C., Jacques, P.F. 2020. Flavonoid intake and MRI markers of brain health in the Framingham Offspring Cohort. Journal of Nutrition. https://doi.org/10.1093/jn/nxaa068.
DOI: https://doi.org/10.1093/jn/nxaa068

Interpretive Summary: Alzheimer's disease and related dementias (ADRD) represents a major global public health problem as there are about 50 million people living with ADRD worldwide and nearly 10 million new cases diagnosed every year. ADRD is characterized by neurodegenerative changes that can be detected using magnetic resonance imaging (MRI). Common signs of ADRD-related neurodegeneration include decreased total and regional brain volumes, which represent brain atrophy, and the presence of lesions referred to as white matter hyperintensities, which represent brain damage due to small vessel disease. Intakes of dietary flavonoids, a class of polyphenols found in many plant foods, are associated with a reduced risk of ADRD. However, there are no studies that have examined the association between flavonoids and brain health assessed using MRI. Therefore, we sought to address this knowledge gap by exploring the association between dietary flavonoid intake and ADRD-associated changes in brain structures based on MRI. While we saw no association between flavonoid intakes and brain atrophy, our results suggest that higher flavonoid intakes may lower ADRD risk by reducing white matter hyperintensity volume.

Technical Abstract: Background: Although greater flavonoid intake is associated with a reduced risk of Alzheimer's disease and related dementias (ADRD), evidence relating dietary flavonoid intake to brain health based on magnetic resonance imaging (MRI) is lacking. Objective: To explore the association between dietary flavonoid intake and MRI measures of brain health including total brain tissue volume (TBV), white matter hyperintensities volume (WMHV), and hippocampal volume (HPV). Methods: Eligible subjects included members of the Framingham Heart Study Offspring Cohort who were free of stroke at exam 7 and had at least one valid food frequency questionnaire from exams 5, 6, or 7 (n=2086, mean age=60.6 years). Flavonoid intakes represented the cumulative average of intakes across the 3 exams and were categorized based on quartiles categories of intake. TBV, WMHV, and HPV were assessed at exam 7. Multiple linear regression models were used to examine the cross-sectional association between total and the 6 classes of flavonoids and the three aforementioned MRI measures. Results: We observed significant inverse trends between intakes of flavan-3-ols (P=0.01), flavonoid polymers (P=0.01), and total flavonoids (P=0.01) and WMHV. The mean WMHV of those in the highest quartile category of flavan-3-ols (P=0.03) and flavonoid polymers (P=0.04) intake were significantly smaller relative to those in the lowest quartile category after accounting for important demographic, lifestyle and clinical factors. However, this did not hold for total flavonoids. TBV and HPV were not associated with dietary flavonoid intake following the adjustment for important potential confounders. Conclusions: Our results contribute to the literature on flavonoids and ADRD by suggesting that higher flavonoid intakes may affect risk by reducing WMHV, a marker strongly associated with cognitive impairment and ADRD.