Effects of Walnuts on Innate, Acquired and Gut Immunity in Older Adults With Overweight: A Randomized Controlled Trial
Overview
- Phase
- Not Applicable
- Status
- Completed
- Sponsor
- Loma Linda University
- Enrollment
- 52
- Locations
- 1
- Primary Endpoint
- changes in lymphocyte activity
Overview
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).
Study Design
- Study Type
- Interventional
- 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
Eligibility Criteria
- Ages
- 55 Years to 75 Years (Adult, Older Adult)
- Sex
- All
- Accepts 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
Outcomes
Primary Outcomes
changes in lymphocyte activity
Time Frame: baseline to 12 weeks
The production of lymphocytes will be measured in the supernatant using Enzyme linked immunosorbent assay (ELISA)
changes in cytokine production
Time Frame: 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
Time Frame: 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
Time Frame: 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
Time Frame: baseline to 12 weeks
changes in Immunoglobulin A will be determined using high performance liquid chromatography-mass spectrometry (HPLC-MS)
changes in lymphocyte populations
Time Frame: 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 concentration of Calprotectin in feces
Time Frame: baseline to 12 weeks
changes in Calprotectin will be determined using high performance liquid chromatography-mass spectrometry (HPLC-MS)
Changes in concentration of small chain fatty in feces
Time Frame: baseline to 12 weeks
changes in Small chain fatty acids will be determined using high performance liquid chromatography-mass spectrometry (HPLC-MS)
Secondary Outcomes
- changes in upper respiratory infection questionnaire score(baseline to 12 weeks)
Investigators
Joan Sabate,DrPH, MD
Professor Nutrition and Epidemiology
Loma Linda University