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.
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 Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
DOUBLE
Enrollment
52
walnuts will provide 15% of the total energy
continue with habitual diet and abstain from walnuts
Loma Linda University School of Public Health
Loma Linda, California, United States
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
Time frame: baseline to 12 weeks
changes in lymphocyte activity
The production of lymphocytes will be measured in the supernatant using Enzyme linked immunosorbent assay (ELISA)
Time frame: 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)
Time frame: 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.
Time frame: 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.
Time frame: 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)
Time frame: baseline to 12 weeks
Changes in concentration of Calprotectin in feces
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changes in Calprotectin will be determined using high performance liquid chromatography-mass spectrometry (HPLC-MS)
Time frame: 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)
Time frame: baseline to 12 weeks
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.
Time frame: baseline to 12 weeks