Scientific Study

Background: Prediabetes is increasingly 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. Objective: 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. Research design and methods: This 24-week, open-label, parallel-arm randomized controlled trial was conducted at a tertiary care centre in New Delhi. Sixty adults aged 40-60 years with prediabetes were randomized 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 weeks 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 (hs-CRP) were also measured. Results: At 24 weeks, the almond group showed significant improvements in executive function (OTS; β = -2.5, 95 % CI: -4.4 -0.6, p = 0.011), and in processing speed (RTI; β= 73.8, 95 % CI: 25.7-122.0, p = 0.003; β = 39.3, 95 % CI: 9.4-69.6, p= 0.011) compared with controls. There were also significant reductions in weight, BMI, waist circumference, fasting and postprandial glucose, HbA1c, 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), improved plasma α-tocopherol and glycemic control in Asian Indians with prediabetes. These findings suggest that almonds may provide dual cognitive and metabolic benefits in this high-risk population. However, the moderate sample size and 24-week duration warrant confirmation in larger and longer-term trials.

https://doi.org/10.1016/j.tjnut.2026.101484