Mediterranean diet and brain structure in a multiethnic elderly cohort

Abstract

Objective: To determine whether higher adherence to a Mediterranean-type diet (MeDi) is related with larger MRI-measured brain volume or cortical thickness.

Methods: In this cross-sectional study, high-resolution structural MRI was collected on 674 elderly (mean age 80.1 years) adults without dementia who participated in a community-based, multiethnic cohort. Dietary information was collected via a food frequency questionnaire. Total brain volume (TBV), total gray matter volume (TGMV), total white matter volume (TWMV), mean cortical thickness (mCT), and regional volume or CT were derived from MRI scans using FreeSurfer program. We examined the association of MeDi (scored as 0-9) and individual food groups with brain volume and thickness using regression models adjusted for age, sex, ethnicity, education, body mass index, diabetes, and cognition.

Results: Compared to lower MeDi adherence (0-4), higher adherence (5-9) was associated with 13.11 (p = 0.007), 5.00 (p = 0.05), and 6.41 (p = 0.05) milliliter larger TBV, TGMV, and TWMV, respectively. Higher fish (b = 7.06, p = 0.006) and lower meat (b = 8.42, p = 0.002) intakes were associated with larger TGMV. Lower meat intake was also associated with larger TBV (b = 12.20, p = 0.02). Higher fish intake was associated with 0.019 mm (p = 0.03) larger mCT. Volumes of cingulate cortex, parietal lobe, temporal lobe, and hippocampus and CT of the superior-frontal region were associated with the dietary factors.

Conclusions: Among older adults, MeDi adherence was associated with less brain atrophy, with an effect similar to 5 years of aging. Higher fish and lower meat intake might be the 2 key food elements that contribute to the benefits of MeDi on brain structure.

Figure. Association of Mediterranean diet, fish, and meat with brain volume and cortical thickness

(A) Mean levels (intracranial-adjusted residuals) of total brain volume (TBV), total gray matter volume (TGMV), and total white matter volume (TWMV) among participants with low (score 0–2), middle (score 3–5), and high (score 6–9) levels of adherence to the Mediterranean diet (MeDi), among tertiles of fish consumption (caloric intake adjusted residuals), and among tertiles of meat consumption (caloric intake adjusted residuals). (B) Mean cortical thickness by levels of MeDi, fish, and meat consumption.