Impact of Snack Foods on Immune Response After Flu Vaccination

Snack Foods and Their Impact on Immune Optimisation to the Influenza Vaccination: a Randomised Controlled Trial of a Vaccination Model of Immune Response

This study is testing whether changing your usual snacks to healthier options can improve how well your immune system responds to the flu vaccine in healthy middle-aged adults.

Quick facts

• Phase: Not applicable
• Study type: Interventional
• Enrollment: 88 (estimated)
• Ages: 40 Years to 64 Years
• Sex: All
• Sponsor: King's College London (Academic / other)
• Drugs / interventions: chemotherapy
• Locations: 1 site (London)
• Trial ID: NCT05515263 on ClinicalTrials.gov

What this trial studies

This study evaluates how replacing usual snacks with alternative snack foods affects the immune response to influenza vaccination in healthy, middle-aged adults. It focuses on the role of nutrition in supporting immune function, particularly through snack consumption, which constitutes a significant portion of daily energy intake. Participants will be randomly assigned to either an intervention group receiving alternative snacks or a control group with usual snacks, with immune responses measured through seroconversion rates and other immunological markers. The intervention lasts for 8 weeks, with vaccination occurring at the midpoint and follow-up for upper respiratory symptoms three months post-vaccination.

Who should consider this trial

Good fit: Ideal candidates are healthy men and women aged 40-64 with a BMI between 18.50 and 29.99 who regularly consume snacks.

Not a fit: Patients with allergies to intervention products or those with immunodeficiency or chronic inflammatory diseases may not benefit from this study.

Why it matters

Potential benefit: If successful, this study could enhance the effectiveness of influenza vaccinations through dietary modifications.

How similar studies have performed: While the specific approach of this study is novel, previous research has indicated that nutrition can significantly impact immune responses.

Eligibility criteria

Inclusion Criteria:

1. Men or women, aged between 40-64 years
2. Body mass index (BMI) of 18.50 - 29.99 kg/m2
3. Individuals who regularly consume snacks (≥2 per day, excluding fruit, vegetable, nut and seed snacks)
4. Fibre intake \<30 g/d
5. Willing to avoid receiving any vaccination (except for COVID-19 vaccination) from one month prior to the baseline visit until completion of the 8-week intervention period
6. Willing to avoid receiving any COVID-19 vaccination/booster between week 2 and week 8 of the intervention period
7. Willing to discontinue use of prebiotics and probiotics during the trial
8. Willing to follow the protocol and provide consent

Exclusion Criteria:

1. Allergy or intolerance to any intervention products
2. Dislike of any intervention products
3. Immunodeficiency/immunosuppression due to disease or medication, such as:

   * Chronic inflammatory disease or autoimmune disease (e.g., rheumatoid arthritis, inflammatory bowel disease, psoriasis) or primary or secondary immunodeficiency disease (e.g., HIV infection)
   * Ongoing therapy with immunomodulators or immunosuppressants (e.g., chemotherapy, oral corticosteroids, daily use of inhaled or nasal corticosteroids)
   * Other immunodeficient state (e.g., asplenia).
4. Medical history of any of the following: diabetes, major active psychiatric conditions (e.g. schizophrenia), current eating disorder, alcohol abuse, active treatment for cancer in the last year, severe neurological, endocrine, renal, cardiac or pulmonary disease (or any other chronic medical condition), severe oesophagitis, gastritis or duodenitis, active diverticulitis or intestinal/colonic strictures, Coeliac disease, Crohn's disease or Ulcerative colitis, stem cell or organ transplant, gut resection surgery, bleeding disorder, anaphylaxis or any other major or chronic condition known to impact study outcome measures.
5. Ongoing use of antiviral agents, or any other drugs known to impact study outcome measures
6. Use of immunoglobulins and/or any blood products within the three months prior to vaccination
7. Ongoing use of anticoagulants (e.g., warfarin)
8. Antibiotic treatment in the month prior to the start of the study
9. Consumption of probiotics or prebiotic products within the four weeks prior to the start of the study
10. History of severe adverse reaction and/or allergic reaction associated with the influenza vaccine or any other vaccine
11. Known allergy or hypersensitivity to any component of the vaccine including: sodium chloride, potassium chloride, magnesium chloride hexahydrate, disodium phosphate dihydrate, potassium dihydrogen phosphate; and possible trace residues: beta-propiolactone, cetyltrimethylammonium bromide, and polysorbate 80
12. Suffered from influenza illness in the six months prior to the start of the study
13. For participants recruited on or before 30/06/2023, exclusion criteria is: already vaccinated with any influenza vaccine licensed for the 2022/2023 season; For participants recruited after 30/06/2023, exclusion criteria is: already vaccinated with any influenza vaccine licensed for the 2023/2024 season
14. Received any influenza vaccination within six months prior to the start of the study
15. Received any other vaccinations within one month prior to the start of the study (except for COVID-19 vaccination)
16. Women who are pregnant, lactating or planning pregnancy
17. Ongoing alcohol, drug or medication abuse
18. Unexplained or unintentional weight loss in the past six months

Where this trial is running

London

• King's College London — London, United Kingdom (Recruiting)

Study contacts

• Study coordinator: Alice van der Schoot, MSc

Conditions Immune Response; Immune Function; Gut Health; Gut Microbiota; Snack