Blueberry Supplementation in Midlife for Dementia Risk Reduction

Nutrients
Q1
Apr 2022
Citations:45
Influential Citations:4
Interventional (Human) Studies
86
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Enhanced Details

Methods
Randomized, double-blind, placebo-controlled trial; participants: non-diabetic, overweight men and women aged 50–65 with subjective cognitive decline (BMI ≥25); recruited in the Cincinnati area; 33 enrolled; 6 unavailable for final visit.
Intervention
Blueberry powder, 0.5 cup whole-fruit equivalent daily (one packet) for 12 weeks; consumed once daily with water at a morning or evening meal; participants abstained from all berry fruits 14 days before enrollment and during the intervention.
Results
Blueberry powder for 12 weeks improved phonemic lexical access (COWA) with large effect size (p=0.003, f=0.66) and reduced intrusion errors during verbal learning (p=0.04, f=0.20). There was a significant reduction in fasting insulin at week 12 (p=0.04; from 10.2 to 8.3 µU/mL) without changes in glucose or HbA1c or lipid measures; no between-group differences in BMI, body weight, waist, fasting glucose, HbA1c, or lipids. A trend toward fewer everyday memory complaints, especially encoding-related forgetfulness (EMQ factor 3, p=0.03, f=0.45), was observed. No effects on category lexical access, other memory measures (CVLT learning rate, delayed recall, recognition), or mood. Mitochondrial measures showed a non-significant trend toward increased uncoupling in a small subset (data limited). Overall, supplementation may confer neurocognitive benefits related to executive control and metabolic improvements in midlife adults with insulin resistance and subjective cognitive decline; longer-term studies are needed to confirm and understand mechanisms.
Limitations
Small sample with dropouts (6 missing at final visit); limited mitochondrial data due to sample loss; results derived from a specific population (overweight, non-diabetic midlife adults with subjective cognitive decline); 12-week duration; dietary background anthocyanin exposure not fully controlled.

Abstract

Late-life dementia typically develops over a period of many years beginning in midlife. Prevalence of metabolic disturbance also accelerates in middle age and is a prominent risk factor for dementia. Preliminary studies indicate that blueberry supple...