Walnut and Immunity Study

Study Overview
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Brief Summary
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The main objective of the study is to determine if eating walnuts enhances immune function, in older free-living men and postmenopausal women with overweight.

Detailed Description
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The main objectives of our proposed study are to determine the effect of walnut consumption on innate, acquired, and gut immunity by assessing whether the ingestion of walnuts enhances immune function, in older free-living men and postmenopausal women with overweight. To accomplish these objectives, a randomized controlled, parallel design study is proposed with two groups consuming their habitual diet, but with one (Walnut group) receiving 15% of their total energy as walnuts and the other (Control group) abstaining from eating any walnuts and limited amounts of other tree nuts and peanuts (up to <1 serving/wk).

Official Title
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Effects of Walnuts on Innate, Acquired and Gut Immunity in Older Adults With Overweight: A Randomized Controlled Trial

Conditions
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Immune Response, Upper Respiratory Tract Infection

Intervention / Treatment
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* Dietary Supplement: walnuts
* Dietary Supplement: Habitual diet


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Older men and post-menopausal women aged 55-75 years Have a BMI of 25-32 Being able to commute to Loma Linda University. Not taking medication or supplements that affect immunity Exclusion Criteria: Intolerance or allergy to walnuts Regular intake of walnuts and/or other nuts (>3 ounces per week). Immune system insufficiency or disease. Using immune boosting supplements. Exposure to antibiotics and corticoids immediately prior to the study. Participants with uncontrolled chronic diseases, and relevant psychiatric illness, including major depression will not be included in study Flu vaccination or Covid booster within past 6 months

Ages Eligible for Study
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Minimum Age: 55 Years
Maximum Age: 75 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: This will be a parallel, free-living, randomized controlled trial with 54 men and post-menopausal women
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: walnut group<br>walnut group will receive 15% of their total energy as walnuts | Dietary Supplement: walnuts<br>* walnuts will provide 15% of the total energy<br>|
| Active Comparator: control group<br>continue with habitual diet and abstain from eating walnuts | Dietary Supplement: Habitual diet<br>* continue with habitual diet and abstain from walnuts<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| changes in lymphocyte populations | Immunophenotyping will be performed by flow cytometry to measure the number of T helper, T cytotoxic, Naïve and memory cells and B cells | baseline to 12 weeks | 
| changes in lymphocyte activity | The production of lymphocytes will be measured in the supernatant using Enzyme linked immunosorbent assay (ELISA) | baseline to 12 weeks | 
| changes in cytokine production | The cytokines produced due to lymphocyte activity will be measured in the supernatant using Enzyme linked immunosorbent assay (ELISA) | baseline to 12 weeks | 
| changes in serum inflammatory cytokine concentration | changes in the concentrations of the inflammatory cytokines will be performed on serum using enzyme-linked immunoassay (ELISA) will include hs-CRP, interleukin (IL)-1β, IL-6, TNF-α, IL-10, and IL-4. | baseline to 12 weeks | 
| changes in diversity of immune-modulating and butyrate -producing gut bacteria in feces | DNA extraction from stool samples will be performed using QIAamp DNA Stool Mini kits.69 The QIIME (Quantitative Insights Into Microbial Ecology) software will be used to analyze 16S rRNA gene sequences and determine the effect of the intervention on microbial diversity at the phylum, genus, and operational taxonomic unit levels. | baseline to 12 weeks | 
| Changes in concentration of Immunoglobulin A in feces | changes in Immunoglobulin A will be determined using high performance liquid chromatography-mass spectrometry (HPLC-MS) | baseline to 12 weeks | 
| Changes in concentration of Calprotectin in feces | changes in Calprotectin will be determined using high performance liquid chromatography-mass spectrometry (HPLC-MS) | baseline to 12 weeks | 
| Changes in concentration of small chain fatty in feces | changes in Small chain fatty acids will be determined using high performance liquid chromatography-mass spectrometry (HPLC-MS) | baseline to 12 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| changes in upper respiratory infection questionnaire score | Upper respiratory tract infections will be tracked using the Jackson and Dowling questionnaire. The questionnaire will be completed daily by participants, either manually or electronically , throughout the 12-week study period. The scale for the questionnaire is from 0-42. The higher score means worse outcome. | baseline to 12 weeks | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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walnuts, Immunity, Inflammation