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Research Area: Diabetes

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.

Effect of premeal pistachio supplementation on cardiometabolic risk factors among Asian Indian adults with prediabetes: A randomized controlled trial.

Ashwini, K., K. Abirami, R. Gayathri, S. Sasikala, V. Sudha, S. Shobana, R.G. Jeevan, K. Krishnaswamy, V. Deepika, M. Rajalakshmi, R.M.R. Bai, K. Parkavi, S. Padmavathi, R.M. Anjana, R. Unnikrishnan, F.B. Hu, W.C. Willett, J. Salas-Salvadó, S.N. Bhupathiraju, V. Mohan, 2025. Effect of premeal pistachio supplementation on cardiometabolic risk factors among Asian Indian adults with prediabetes: A randomized controlled trial. J Nutr. 155(3):899-909. https://doi.org/10.1016/j.tjnut.2024.12.005

Background: Asian Indians are susceptible to developing type 2 diabetes at a lower age and often consume diets that are high in glycemic load and low in healthy fats. Objectives: This study aimed to evaluate the effect of 30g prebreakfast and 30g predinner supplementation of pistachios for 12 wk on glycated hemoglobin (HbA1c), other glycemic markers, anthropometry, and lipid profile of Asian Indians with prediabetes. Methods: In a 12-wk parallel arm, randomized controlled trial, we recruited 120 participants with prediabetes based on American Diabetes Association criteria. The intervention group (n = 60) consumed 60g pistachios (30g prebreakfast and predinner) whereas the control group (n = 60) followed a routine diet that excluded nuts. At baseline and 12 wk, we collected blood samples for biochemical analysis, anthropometrics, and 24-h recalls. Participants wore a continuous glucose monitoring (CGM) sensor during the trial’s first and last 2 wk. Urinary N-methyl-trans-4-hydroxy-l-proline (MHP) was measured as a marker of pistachio consumption. Results: A total of 109 participants completed the study (follow-up rate = 90.8%). Compared with participants in the control group, those in the intervention group had significant reductions in HbA1c (mean between-group difference: −0.2; 95% confidence interval: −0.3, −0.1; P < 0.001] with no significant changes in fasting or 2-h post glucose load plasma glucose. Compared with the control group, the intervention group had significant reductions in serum triglyceride, waist circumference, lipid accumulation product, visceral adiposity index, and atherogenic index. Urinary MHP (mg/g creatinine) showed a 62% increase in the intervention compared with the control group (P < 0.05). CGM data revealed significant decreases in the incremental area under the curve, 2-h after breakfast (28%, p=0.01) and after dinner (17%, P = 0.002) in the intervention group compared to the control group. Conclusions: A 12-wk, premeal load of 60g pistachios lowers HbA1c and improves cardiometabolic profile among Asian Indians with prediabetes. This is among the first studies to investigate these effects in this ethnic group.

Brazil nut consumption reduces DNA damage in overweight type 2 diabetes mellitus patients.

Macan, T.P., M.L. Magenis, A.P. Damiani, I.O. Monteiro, G.B. Silveira, R.P. Zaccaron, P.C.L. Silveira, J.P.F. Teixeira, G. Gajski, V.M. Andrade, 2024. Brazil nut consumption reduces DNA damage in overweight type 2 diabetes mellitus patients. Mutat Res Genet Toxicol Environ Mutagen. 895:503739. https://doi.org/10.1016/j.mrgentox.2024.503739

Type 2 diabetes mellitus (T2D) is a metabolic disease, which occurs largely due to unhealthy lifestyle. As oxidative stress is believed to promote T2D, by inducing damage to lipids, proteins, and DNA, appropriate dietary interventions seem critical to prevent, manage, and even reverse this condition. Brazil nuts (Bertholletia excelsa, H.B.K.) are nature’s richest source of selenium, a mineral that has shown several health benefits. Therefore, this study aims to assess the effects of selenium consumption, through Brazil nuts, on biochemical and oxidative stress parameters, and genomic instability in T2D patients. We recruited 133 patients with T2D, registered in the Integrated Clinics of the University of Southern Santa Catarina (Brazil). Participants consumed one Brazil nut a day for six months. Blood samples and exfoliated buccal cells were collected at the beginning and the end of the intervention. The glycemic profile, lipid profile, renal profile and hepatic profile, DNA damage and selenium content were evaluated. A total of 74 participants completed the intervention. Brazil nut consumption increased selenium and GSH levels, GPx, and CAT activity while DCF and nitrites levels decreased. Total thiols increased, and protein carbonyl and MDA levels decreased. Levels of baseline and oxidative DNA damage in T2D patients were significantly decreased, as well as the frequency of micronuclei and nuclear buds. The fasting glucose levels, HDL and LDL cholesterol, and GGT levels that increased significantly in patients with type 2 diabetes were significantly reduced with nut consumption. Our results show an increase in antioxidant activity, along with reductions of protein and lipid oxidation as well as DNA damage, suggesting that Brazil nut consumption could be an ally in reducing oxidative stress and modulating the genomic instability in T2D patients.