Pecan or Pretzel Snacks for Brain Health in Adults 50+

Is this trial a fit for you?

A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.

What this trial studies

This interventional study will randomly assign 60 adults aged 50 and above with cognitive impairment to daily snacking with either pecans or pretzels for three months. Researchers will monitor changes in memory and mood, and will explore potential brain–gut connections by measuring gut bacteria, inflammatory markers, and brain signaling related to the gut–brain axis using fMRI. The trial aims to understand whether snack choice can influence brain function and overall well-being in cognitive impairment. The design includes primary outcomes about cognitive and psychological function, with secondary analyses of biomarkers and gut microbiome changes.

Why it matters

Who can join: the full rules

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 test because it allows the microbial community time to recover and reach a more stable state, ensuring a more accurate and representative snapshot of the gut microbiome composition, since antibiotic usage can significantly reduce microbial diversity.
* Self-reported unstable GI disorder
* likeliness of moving during the trial, lack of transportation, or unavailability at sample collection times

Where it's running

• Texas Tech University Health Sciences Center
  Lubbock, Texas, United States Recruiting

Study contacts

• Principal investigator: Chwan-Li (Leslie) Shen, PhD — Texas Tech University Health Sciences Center School of Medicine
• Study coordinator: Chwan-Li (Leslie) Shen, PhD
• Email: leslie.shen@ttuhsc.edu
• Phone: 806-743-2815

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How to take part

1. Review the eligibility criteria above with your treating physician.
2. Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
3. Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.