Peanuts may improve regional brain insulin response

A randomized crossover trial found changes in insulin-induced cerebral blood flow following 16 weeks of daily peanut consumption, although the connection to improved memory remains unclear.

By
Andrea Surnit
October 16, 2026
4 min

MDSpire News

Objective:

To assess whether daily peanut consumption affects brain insulin responsiveness and related metabolic measures in older adults.

Approach:

Design and participants: Randomized, single-blind, controlled crossover trial; 31 adults aged 60–75 completed both study periods.
Interventions: Participants consumed 60 g of unsalted, skin-roasted peanuts daily for 16 weeks and had a 16-week control period without nuts, separated by an 8-week washout.
Assessments: Researchers measured cerebral blood flow before and 30 minutes after intranasal insulin using arterial spin labeling MRI, alongside metabolic measures and associations with verbal recognition memory.

Key Findings:

Peanut consumption was associated with a statistically significant reduction in insulin-induced cerebral blood flow in one right-hemisphere cluster (mean difference −5.4 mL/100 g/min; volume 552 mm³), spanning portions of memory-related regions.
No significant differences were found in global, gray matter, cortical, or subcortical brain responses; regional changes were not significantly associated with previously reported improvements in verbal recognition memory.
Liver fat, fasting glucose, insulin, insulin resistance, cholesterol, and high-sensitivity C-reactive protein did not change significantly. Triglycerides were lower at week 8, but not at week 16.
Median adherence was 100%. One participant withdrew because of gastrointestinal discomfort; no study-related serious adverse events were reported.

Interpretation:

The authors described the findings as a potentially beneficial effect on regional brain insulin responsiveness, but the study did not establish that these changes contributed to verbal recognition memory improvements.

Limitations:

The small sample limited analyses of associations between brain responses and cognitive outcomes.
Insulin-induced cerebral blood flow is an indirect measure and does not directly establish neuronal insulin signaling.
The control period was not matched for energy or macronutrients, and participants added peanuts without prescribed food replacement, so changes in overall dietary intake could partly explain the findings.

Conclusion:

In this trial, 16 weeks of daily peanut consumption was associated with a region-specific change in insulin-induced cerebral blood flow in older adults; broader brain and metabolic measures were largely unchanged.