TY - JOUR
T1 - Effect of a 2-year diet intervention with walnuts on cognitive decline. The Walnuts and Healthy Aging (WAHA) study
T2 - A randomized controlled trial
AU - Sala-Vila, Aleix
AU - Valls-Pedret, Cinta
AU - Rajaram, Sujatha
AU - Coll-Padrós, Nina
AU - Cofán, Montserrat
AU - Serra-Mir, Mercè
AU - Pérez-Heras, Ana M.
AU - Roth, Irene
AU - Freitas-Simoes, Tania M.
AU - Doménech, Mónica
AU - Calvo, Carlos
AU - López-Illamola, Anna
AU - Bitok, Edward
AU - Buxton, Natalie K.
AU - Huey, Lynnley
AU - Arechiga, Adam
AU - Oda, Keiji
AU - Lee, Grace J.
AU - Corella, Dolores
AU - Vaqué-Alcázar, Lídia
AU - Sala-Llonch, Roser
AU - Bartrés-Faz, David
AU - Sabaté, Joan
AU - Ros, Emilio
N1 - Publisher Copyright:
Copyright © 2020 The Author(s).
PY - 2020/3/1
Y1 - 2020/3/1
N2 - Background: Walnut consumption counteracts oxidative stress and inflammation, 2 drivers of cognitive decline. Clinical data concerning effects on cognition are lacking. Objectives: 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. Methods: 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. Results: 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. Conclusions: 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.
AB - Background: Walnut consumption counteracts oxidative stress and inflammation, 2 drivers of cognitive decline. Clinical data concerning effects on cognition are lacking. Objectives: 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. Methods: 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. Results: 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. Conclusions: 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.
KW - cognition
KW - neuroimaging
KW - nuts
KW - omega-3
KW - α-linolenic acid
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U2 - 10.1093/ajcn/nqz328
DO - 10.1093/ajcn/nqz328
M3 - Article
C2 - 31912155
SN - 0002-9165
VL - 111
SP - 590
EP - 600
JO - American Journal of Clinical Nutrition
JF - American Journal of Clinical Nutrition
IS - 3
ER -