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Completed

NCT Number: NCT05915390

Walnut and Immunity Study

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.

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Key information

Conditions

Immune Response Infections Inflammation Pathologic Processes Pathological Conditions, Signs and Symptoms Respiratory Tract Diseases Respiratory Tract Infections Upper Respiratory Tract Infection

Age range

55 year–75 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Loma Linda University School of Public Health

Loma Linda, California, 92350, United States

About this study

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).

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

walnuts

Dietary Supplement

walnuts will provide 15% of the total energy

Habitual diet

Dietary Supplement

continue with habitual diet and abstain from walnuts

Primary outcomes

  1. 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

  2. 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)

  3. 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)

  4. 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.

  5. 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.

  6. 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)

  7. 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)

  8. 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

  1. changes in upper respiratory infection questionnaire score

    Time frame: 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.

Sponsors and collaborators

Lead sponsor

Loma Linda University

Other

Registry information

Official study title

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

Acronym: walnutimmune

Important dates

Study start
2023
Primary completion
2023
Study completion
2023
First posted
Jun 23, 2023
Registry last updated
Oct 2, 2024

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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