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.

The default-mode network (DMN) is affected by advancing age, where particularly long-range connectivity has been consistently reported to be reduced as compared to young individuals. We examined whether there were any differences in the effects of intermittent theta-burst stimulation *

Age-related changes in the brain connectivity of healthy older adults have been widely studied in recent years, with some differences in the obtained results. Most of these studies showed decreases in general functional connectivity, but they also found increases in some particular regions and areas. Frequently, these studies compared young individuals with older subjects, but few studies compared different age groups only in older populations. The purpose of this study is to analyze whole-brain functional connectivity in healthy older adult groups and its network characteristics through functional segregation. A total of 114 individuals, 48 to 89 years old, were scanned using resting-state functional magnetic resonance imaging in a resting state paradigm and were divided into six different age groups (< 60, 60–64, 65–69, 70–74, 75–79, ≥ 80 years old). A partial correlation analysis, a pooled correlation analysis and a study of 3-cycle regions with prominent connectivity were conducted. Our results showed progressive diminution in the functional connectivity among different age groups and this was particularly pronounced between 75 and 79 years old. The oldest group (≥ 80 years old) showed a slight increase in functional connectivity compared to the other groups. This occurred possibly because of compensatory mechanism in brain functioning. This study provides information on the brain functional characteristics of every age group, with more specific information on the functional progressive decline, and supplies methodological tools to study functional connectivity characteristics. Approval for the study was obtained from the ethics committee of the Comisión de Bioética de la Universidad de Barcelona (approval No. PSI2012-38257) on June 5, 2012, and from the ethics committee of the Barcelona’s Hospital Clínic (approval No. 2009-5306 and 2011-6604) on October 22, 2009 and April 7, 2011 respectively.