Effects of 24-Week Almond Supplementation on Executive Function and Processing Speed in Middle-Aged Asian Indians...

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.

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.

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.

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).

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. This trial was registered at clinicaltrials.gov as NCT05322304.