Snacks and Brain Health

Inclusion Criteria: * men and women \> 50 years-old * self-reported IQCODE (informant questionnaire on cognitive decline in the elderly) average score \< 4.5 * self-reported significant functional impairment (related to cognitive impairment) in basic or advanced activities of daily living as evidenced by the Activities of Daily Living (ADLs) questionnaire. If answers to at least one endorsement in the "NO, dependence due to memory concerns". * Stable medications (≥ 12-week unchanged dose before baseline) with no planned changes during trial. * habitually consume less than two servings (2 ozs = 1/4 cup) of nuts or nut spreads per week * willing to accept randomization Exclusion Criteria: * reported nut allergy or intolerance * self-reported untreated hypothyroidism, severe liver disease, or end-stage chronic kidney disease * heavy alcohol drinker: in the past 3 months: men ≥14 drinks/week or women ≥7 drinks/week * recent (\<1 month) appearance of diarrhea or hematochezia before study intervention begins. Rationale: A one-month waiting period after diarrhea or hematochezia (blood in stool) is recommended for a gut microbiome test to ensure the results accurately reflect the state and microbial composition, since diarrhea and hematochezia can significantly alter the gut environment and skew test results. * recent (\<1 month) exposure to antibiotics before study intervention begins. Rationale: A one-month waiting period after antibiotics is recommended for a gut microbiome tes…