Effect of Almonds on Immune Strength and Response to Flu Vaccination in Overweight Older Men and Postmenopausal Women: A Randomized Controlled Study (Almond Immune)

Effect of Daily Consumption of Almonds on Immune Strength and Response to Flu Vaccination in Overweight Middle -Aged Men: A Randomized Controlled Study

This research study will test the effects of almonds on immune functions and immune response to influenza vaccine in overweight middle-aged men and postmenopausal women

Study Overview

• Status: Completed
• Conditions: Inflammation; Immune Response
• Intervention / Treatment: Dietary supplement: Almond group; Dietary supplement: Control Group

Detailed Description

The proposed study is a parallel-group, free-living, observer-blind, randomized controlled dietary intervention trial on 66 overweight middle-aged men and post menopausal women. This study will be carried out in two phases: Phase 1 will examine the effects of almonds on clinically relevant markers of immune function, and Phase 2 will assess the antibody response to influenza vaccination following almond consumption. Participants will attend a baseline clinic and will be randomized to one of two groups. The Almond group will receive 15% of daily energy intake in the form of almonds as a snack and the Control group will continue thier usual diet but completely avoid almonds and restrict other nuts to less than 2 servings per week. The intervention will be for 12 weeks, at which time both group participants will receive the influenza vaccination, and continue the same dietary intervention for another 28 weeks.

• Study Type: Interventional
• Enrollment (Actual): 61
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • California
    • Loma Linda, California, United States, 92350
      • Loma Linda University School of Public Health

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 40 years to 65 years (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Overweight men and post menopausal women (Basal Metabolic Index 25-32)
• Age limit between 40-70 years
• Be able to commute to Loma Linda University

Exclusion Criteria:

• Intolerance or allergy to almonds
• Bad dentures, inability to chew almonds
• Regular intake of almonds and or other nuts
• Use of immune boosting supplements
• Exposure to antibiotics and corticosteroids immediately prior to study
• Have received influenza vaccination in past 10 months
• Uncontrolled chronic disease and psychiatric illness

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Almonds; The almond group will receive 15% of their daily energy intake in the form of almonds	Dietary supplement: Almond group; Participants in the Almond group will receive 15% of their daily energy intake in the form of almonds as a snack
Placebo Comparator: Control; The control group will be encouraged to continue their usual diet but completely avoid almonds and restrict other nuts to less than 2 servings per week	Dietary supplement: Control Group; The control group will continue their usual diet but will completely avoid almonds and restrict other nuts to less than 2 servings per week

What is the study measuring?

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 and cytokine production	PBMC cells will be separated from blood, activated and cultured using phytohemagglutinin (PHA). Inflammatory cytokine production will be measured in the resulting supernatant using ELISA	baseline to 12 weeks
changes in natural killer (NK) cell activity	The NK degranulation assay will be performed on blood samples. The test will be conducted using a modified flow cytometry method that measures the expression of CD107a	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)	baseline to 12 weeks
changes in complete blood count (CBC)	changes in the complete blood count will be performed on whole blood with the use of an automated hematology analyzer at a certified clinical facility	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 28-week study period. The scale for the questionnaire is from 0-42. The higher score means worse outcome.	baseline to 28 weeks
changes in blood zinc levels	Zinc levels in blood will be analyzed in trace element- free tubes and assayed by atomic absorption spectrophotometry using standard reference material obtained from the National Institute of Standards and Technology to check the accuracy and precision of the determinations	baseline to 12 weeks

Collaborators and Investigators

• Sponsor: Loma Linda University
• Investigators: Principal Investigator: Joan Sabate, DrPH, Loma Linda University

Study record dates

Study Major Dates

• Study Start (Actual): August 12, 2021
• Primary Completion (Actual): May 10, 2023
• Study Completion (Actual): May 10, 2023

Study Registration Dates

• First Submitted: July 6, 2021
• First Submitted That Met QC Criteria: August 26, 2021
• First Posted (Actual): September 2, 2021

Study Record Updates

• Last Update Posted (Estimated): December 9, 2025
• Last Update Submitted That Met QC Criteria: December 2, 2025
• Last Verified: December 1, 2025

More Information

Terms related to this study

• Keywords: Inflammation; Immunity; Almonds
• Additional Relevant MeSH Terms: Pathologic Processes; Pathological Conditions, Signs and Symptoms; Inflammation; Investigative Techniques; Epidemiologic Research Design; Epidemiologic Methods; Research Design; Methods; Control Groups
• Other Study ID Numbers: 5210259

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No