Archive

Research Area: Cognitive Health

Effects of 24-week almond supplementation on executive function and processing speed in middle-aged Asian Indians with prediabetes: an open-label randomized controlled trial.

Gulati, S., A. Misra, R. Tiwari, R.M. Pandey, M. Sharma, 2026. Effects of 24-week almond supplementation on executive function and processing speed in middle-aged Asian Indians with prediabetes: an open-label randomized controlled trial. J Nutr. 156(5):101484. doi: 10.1016/j.tjnut.2026.101484.

Background: Prediabetes is potentially recognized as a stage of heightened risk not only for diabetes but also for early cognitive decline, driven by insulin resistance, oxidative stress, and low-grade inflammation. Objectives: The aim of this study was to evaluate the effect of daily almond supplementation on cognitive performance and biochemical markers in middle-aged Asian Indians with prediabetes, who are at high risk for metabolic and cognitive decline. Methods: This 24-wk, open-label, parallel-arm randomized controlled trial was conducted at a tertiary care center in New Delhi. A total of 60 adults aged 40-60 y with prediabetes were randomly assigned to an almond group (n = 29; almonds providing 20% of daily energy with diet and exercise) or a control group (n = 31; isocaloric diet and exercise without almonds). Cognitive function was assessed at baseline and 24 wk using the Cambridge neuropsychological test automated battery (CANTAB), covering executive function, memory, attention, processing speed, and working memory. Anthropometry, glycemia, plasma α-tocopherol, thiobarbituric acid reactive substances (TBARS), and high-sensitivity C-reactive protein were also measured. Results: At 24 wk, the almond group showed significant improvements in executive function [One Touch Stockings of Cambridge; β = -2.5, 95% confidence interval (CI): -4.4, -0.6, P = 0.01] and in processing speed (reaction time; β = 73.8, 95% CI: 25.7, 122.0, P = 0.003; β = 39.3, 95% CI: 9.4, 69.1, P = 0.011) compared with controls. There were also significant reductions in weight, body mass index, waist circumference, fasting and postprandial glucose, glycosylated hemoglobin, and TBARS, along with increased plasma α-tocopherol (all P < 0.05). Conclusions: Six months of almond supplementation improved executive function, processing speed, and overall cognition, reduced oxidative stress (TBARS), and improved plasma α-tocopherol and glycemia in Asian Indians with prediabetes. These findings suggest that almonds provide dual cognitive and metabolic benefits in this high-risk population. However, the moderate sample size and 24-wk duration warrant confirmation in larger and longer-term trials.

Pecans and human health: distinctive benefits of an American nut.

Sandhu, A.K., I. Edirisinghe, B. Burton-Freeman, 2025. Pecans and human health: distinctive benefits of an American nut. Nutrients. 17, 3686. https://doi.org/10.3390/nu17233686

Pecans are a tree nut native to America with a rich content of unsaturated fatty acids, minerals, fiber, and a diverse array of bioactive components, including polyphenols, tocopherols, and phytosterols. This review summarizes variations in the phenolic composition of pecans from various parts of the world based on cultivar, maturity stage, postharvest storage, and processing. Additionally, the review delves into the bio-accessibility and bioavailability of bioactive components from pecans and their potential influence on diet quality, body weight, satiety, cardiometabolic, brain and gut health. Data from human clinical trials suggest that replacing foods/snacks with pecans improves overall diet quality and lipid profiles. However, inconsistent effects are observed on vascular function, glycemia, and inflammation. Body weight changes after pecan intake are reported as neutral, with promising results on satiety peptides and appetite regulation. Cognition and gut health are emerging areas of research with very limited data from both human and preclinical models, warranting further investigation. Overall, the current literature supports the cardiometabolic benefits of pecans within healthy dietary patterns. Future research should focus on well-controlled studies targeting at-risk populations to understand mechanistic endpoints such as metabolomics, microbiome, and vascular function assessments to substantiate the role of pecans in dietary guidance.

Serum Galectin-9 and Decorin in relation to brain aging and the green-Mediterranean diet: A secondary analysis of the DIRECT PLUS randomized trial.

Pachter, D., A. Yaskolka Meir, A. Kaplan, G. Tsaban, H. Zelicha, E. Rinott, G. Levakov, O. Finkelstein, I. Shelef, M. Salti, F. Beyer, V. Witte, N. Klöting, B. Isermann, U. Ceglarek, T. Riklin Raviv, M. Blüher, M. Stumvoll, D.D. Wang, F.B. Hu, M.J. Stampfer, G. Avidan, I. Shai, 2025. Serum Galectin-9 and Decorin in relation to brain aging and the green-Mediterranean diet: A secondary analysis of the DIRECT PLUS randomized trial. Clin Nutr. 53:99-108. doi: 10.1016/j.clnu.2025.08.021.

Background and aims: We explored whether changes in serum proteomic profiles differed between participants with distinct brain aging trajectories, and whether these changes were influenced by dietary intervention. Methods: In this secondary analysis of the 18-month DIRECT PLUS trial, 294 participants were randomized to one of three arms: 1) Healthy dietary guidelines (HDG); 2) Mediterranean (MED) diet (+440 mg/day polyphenols from walnuts); or 3) low red/processed meat green-MED diet (+1240 mg/day polyphenols from walnuts, Mankai plant, and green tea). We measured 87 serum proteins (Olink-CVDII). We used Magnetic-Resonance-Imaging (MRI)-assessed 3D-T1-weighted brain scans for brain age calculation (by convolutional neural network) to identify protein markers reflecting the brain age gap (BAG; deviation of MRI-assessed brain age from chronological age). Results: At baseline, lower weight, waist circumference, diastolic blood pressure, and HbA1c parameters were associated with a younger brain age than expected. Specifically, higher levels of two proteins, Galectin-9 (Gal-9) and Decorin (DCN), were associated with accelerated brain aging (larger BAG). A proteomics principal component analysis (PCA) revealed a difference in PC1 between the two time-points for participants with accelerated brain aging. Between baseline and 18 months, Gal-9 significantly decreased among individuals who completed the intervention with attenuated brain aging, while DCN significantly increased among those who completed the trial with accelerated brain aging. A significant interaction was observed between the green-MED diet and proteomics PCA, resulting in a beneficial change compared to the HDG. Participants in the green-MED diet significantly decreased Gal-9 compared to the HDG diet and from baseline. Conclusions: Higher serum levels of Gal-9 and DCN may indicate an acceleration of brain aging and could be reduced by a green-MED/high-polyphenol (green tea and Mankai) and low-red/processed meat diet.

Red blood cell omega-3 status and longitudinal cognition in individuals at risk of Alzheimer’s disease.

Lázaro, I., A. Brugulat-Serrat, M. Suárez-Calvet, K. Fauria, C. Minguillon, J.D. Gispert, J.L. Molinuevo, W.S. Harris, G. Sánchez-Benavides, O. Grau-Rivera, A. Sala-Vila, 2025. Red blood cell omega-3 status and longitudinal cognition in individuals at risk of Alzheimer’s disease. J Nutr. S0022-3166(25)00576-0. doi: 10.1016/j.tjnut.2025.09.032.

Background. Many observational studies on dietary omega-3 fatty acids (FAs) and cognition focused on docosahexaenoic acid (DHA), because its significant role in brain. There is growing interest in whether other omega-3 FAs may also display cognitive benefits. Objectives. To examine the associations between the blood levels of three different omega-3 FAs (DHA; eicosapentaenoic acid [EPA]; and alpha-linolenic acid [ALA]) and 3-year changes in cognitive performance in a cohort of cognitively unimpaired individuals at high risk of Alzheimer’s disease (AD). Methods. Prospective longitudinal study conducted in 323 participants from the ALFA (ALzheimer and FAmilies) Study. We determined the baseline levels of omega-3 FAs in red blood cells (RBCs) using gas-chromatography. Participants underwent a comprehensive neuropsychological battery at baseline and after 3 yrs. We studied cognitive outcomes as rate of change between visits. We first constructed multivariate models to examine the association between RBC-DHA and the preclinical Alzheimer’s cognitive composite (PACC) score, also examining the effect of gender, APOE-ε4 carriership, and AD pathology (defined cerebrospinal fluid amyloid-beta and tau). As exploratory analysis, we examined associations between RBC-EPA and RBC-ALA with PACC, as well as those between omega-3 FAs and composite z-scores for attention, executive functioning, episodic memory, visual processing, and language domains. Results. RBC-DHA was associated with a positive (improved) global cognition (PACC) rate of change (estimate = 0.011, 95% confidence interval [CI] = 0.001;0.021, P = 0.024). No statistically significant interactions were observed for sex, APOE-ε4 carriership, or AD pathology. Higher RBC-ALA status was associated with positive rate of change (better performing) in visual processing (estimate = 0.425, 95% CI = 0.168;0.682, P = 0.001). Conclusions. In individuals at risk of AD, RBC-DHA and RBC-ALA showed positive associations with longitudinal cognition. These findings add to the observational evidence linking omega-3 FAs with improved brain health.