Daily consumption of unsalted, skin-roasted peanuts beneficially affects regional brain insulin responsiveness in older adults: results of a longer-term randomized controlled trial.
Lucia Kerkhof, Ronald P Mensink, Jogchum Plat et al.
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In 30 seconds
This randomized, single-blind, controlled crossover trial examined whether peanut intake altered brain insulin responsiveness in 31 older adults (67 ± 4 years). Participants consumed 60 g day -1 of unsalted, skin-roasted peanuts or followed a no-peanut control period for 16 weeks, with an 8-week washout. After peanut intake, intranasal insulin elicited a lower cerebral blood flow response in one right-hemisphere region than during control (mean difference: -5.4 ± 5.4 mL per 100 g tissue per min; cluster size = 552 mm 3 , P = 0.044). The authors interpret this as a potentially beneficial change in regional brain insulin responsiveness.
Key findings
- Peanut intake was associated with a reduced insulin-related cerebral blood flow response in one right-hemisphere region versus control (mean difference: -5.4 ± 5.4 mL per 100 g tissue per min; P = 0.044).
- Atlas localization assigned the highest average probabilities to the lingual gyrus (20%), hippocampus (14%), and parahippocampal gyrus (11%).
- Intrahepatic lipid content and measured markers of glucose homeostasis, lipid metabolism, and low-grade systemic inflammation remained unchanged.
Why it matters
The findings add a possible brain-level correlate to previously reported memory benefits of peanut intake in older adults. They also illustrate that a dietary intervention may be associated with regional changes in an insulin-response imaging measure without detectable changes in the measured hepatic or circulating metabolic markers. The clinical meaning of this imaging response remains uncertain.
What to keep in mind
The trial included 31 participants, and the reported outcome was an imaging measure of cerebral blood flow response rather than a direct clinical cognitive outcome.