Immune Response, Upper Respiratory Tract Infection
Conditions
Keywords
walnuts, Immunity, Inflammation
Brief summary
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
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).
Interventions
DIETARY_SUPPLEMENTwalnuts
walnuts will provide 15% of the total energy
DIETARY_SUPPLEMENTHabitual diet
continue with habitual diet and abstain from walnuts
Sponsors
Loma Linda University
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
PREVENTION
Masking
DOUBLE (Investigator, Outcomes Assessor)
Masking description
The investigator and outcome assessor will not be aware which participant is in what arm. The participant and the care provider will know about the treatment allocation
Intervention model description
This will be a parallel, free-living, randomized controlled trial with 54 men and post-menopausal women
Eligibility
Sex/Gender
ALL
Age
55 Years to 75 Years
Healthy volunteers
Yes
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
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Changes in concentration of small chain fatty in feces | baseline to 12 weeks | changes in Small chain fatty acids will be determined using high performance liquid chromatography-mass spectrometry (HPLC-MS) |
| changes in lymphocyte populations | baseline to 12 weeks | Immunophenotyping will be performed by flow cytometry to measure the number of T helper, T cytotoxic, Naïve and memory cells and B cells |
| changes in lymphocyte activity | baseline to 12 weeks | The production of lymphocytes will be measured in the supernatant using Enzyme linked immunosorbent assay (ELISA) |
| changes in cytokine production | baseline to 12 weeks | The cytokines produced due to lymphocyte activity will be measured in the supernatant using Enzyme linked immunosorbent assay (ELISA) |
| changes in serum inflammatory cytokine concentration | baseline to 12 weeks | 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. |
| changes in diversity of immune-modulating and butyrate -producing gut bacteria in feces | baseline to 12 weeks | 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. |
| Changes in concentration of Immunoglobulin A in feces | baseline to 12 weeks | changes in Immunoglobulin A will be determined using high performance liquid chromatography-mass spectrometry (HPLC-MS) |
| Changes in concentration of Calprotectin in feces | baseline to 12 weeks | changes in Calprotectin will be determined using high performance liquid chromatography-mass spectrometry (HPLC-MS) |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| changes in upper respiratory infection questionnaire score | baseline to 12 weeks | 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. |
Countries
United States
Outcome results
None listed