Sala-Vila 2020 / WAHA study

Study ID(s) and Acronym(s)
WAHA study / NCT01634841 / Walnuts And Healthy Aging study
Current Status of Trial
Completed
Study Aim
Cognitive Enhancement (healthy)
Study Design
RCT
Blinding
No blinding
Intervention type
Pharmacological
Intervention
Diet enriched with walnuts
Dosage and Duration
Randomly allocated 708 free-living elders (63-79 y, 68% women) to a diet enriched with walnuts at ~15% energy (30-60 g/d) or a control diet (abstention from walnuts). Administered a comprehensive neurocognitive test battery at baseline and 2 y
Absolute Number of Participants
708
Health Status/Diagnosis
Healthy elderly
Country or Countries of Recruitment
Spain
Primary outcomes
Change in the global cognition composite
Key Points
"Walnuts were well tolerated and compliance was good. Modified intention-to-treat analyses (n = 657) uncovered no between-group differences in the global cognitive composite, with mean changes of -0.072 (95% CI: -0.100, -0.043) in the walnut diet group and -0.086 (95% CI: -0.115, -0.057) in the control diet group (P = 0.491). Post hoc analyses revealed significant differences in the Barcelona cohort, with unadjusted changes of -0.037 (95% CI: -0.077, 0.002) in the walnut group and -0.097 (95% CI: -0.137, -0.057) in controls (P = 0.040). Results of brain fMRI in a subset of Barcelona participants indicated greater functional network recruitment in a working memory task in controls. CONCLUSION(S): Walnut supplementation for 2 y had no effect on cognition in healthy elders. However, brain fMRI and post hoc analyses by site suggest that walnuts might delay cognitive decline in subgroups at higher risk. These encouraging but inconclusive results warrant further investigation, particularly targeting disadvantaged populations, in whom greatest benefit could be expected.This trial was registered at clinicaltrials.gov as NCT01634841" Sala-Vila 2020
Study log
BACKGROUND: Walnut consumption counteracts oxidative stress and inflammation, 2 drivers of cognitive decline. Clinical data concerning effects on cognition are lacking. OBJECTIVE(S): The Walnuts And Healthy Aging study is a 2-center (Barcelona, Spain; Loma Linda, CA) randomized controlled trial examining the cognitive effects of a 2-y walnut intervention in cognitively healthy elders. METHOD(S): We randomly allocated 708 free-living elders (63-79 y, 68% women) to a diet enriched with walnuts at ~15% energy (30-60 g/d) or a control diet (abstention from walnuts). We administered a comprehensive neurocognitive test battery at baseline and 2 y. Change in the global cognition composite was the primary outcome. We performed repeated structural and functional brain MRI in 108 Barcelona participants. RESULT(S): A total of 636 participants completed the intervention. Besides differences in nutrient intake, participants from Barcelona smoked more, were less educated, and had lower baseline neuropsychological test scores than those from Loma Linda. Walnuts were well tolerated and compliance was good. Modified intention-to-treat analyses (n = 657) uncovered no between-group differences in the global cognitive composite, with mean changes of -0.072 (95% CI: -0.100, -0.043) in the walnut diet group and -0.086 (95% CI: -0.115, -0.057) in the control diet group (P = 0.491). Post hoc analyses revealed significant differences in the Barcelona cohort, with unadjusted changes of -0.037 (95% CI: -0.077, 0.002) in the walnut group and -0.097 (95% CI: -0.137, -0.057) in controls (P = 0.040). Results of brain fMRI in a subset of Barcelona participants indicated greater functional network recruitment in a working memory task in controls. CONCLUSION(S): Walnut supplementation for 2 y had no effect on cognition in healthy elders. However, brain fMRI and post hoc analyses by site suggest that walnuts might delay cognitive decline in subgroups at higher risk. These encouraging but inconclusive results warrant further investigation, particularly targeting disadvantaged populations, in whom greatest benefit could be expected.This trial was registered at clinicaltrials.gov as NCT01634841.Copyright © The Author(s) 2020.