Could a fiber supplement boost your vaccine?

NCT ID NCT04543877

Completed Knowledge-focused Sponsor: USDA, Western Human Nutrition Research Center Source: ClinicalTrials.gov ↗

First seen Jun 25, 2026 · Last updated Jun 27, 2026 · Updated 1 time

Summary

This study looked at whether adding a fiber supplement (inulin) to a low-fiber diet could increase helpful gut bacteria and improve the immune response to a typhoid vaccine. Sixty healthy adults with low fiber intake took either inulin or a placebo for five weeks, and all received the typhoid vaccine. Researchers measured changes in gut bacteria, inflammation, and vaccine antibody levels.

What this could mean

Our plain-language read of the trial. This is informational only — not medical advice or a prediction.

Active substance: Inulin (a type of dietary fiber)
What this could lead to: If it works, this could point toward simple dietary changes to improve vaccine effectiveness and gut health.
What could go wrong: This is a very early, small study (60 people) looking at lab markers, not actual disease outcomes. Results may not apply to other vaccines or populations.

This is an AI summary of the original study and may miss details. Read our disclaimer.

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Conditions

The condition(s) this trial relates to.

Inflammation inflammatory disease typhoid fever

As listed by the trial registrant

The condition terms exactly as the trial's registrant entered them.

INFLAMMATION INTESTINAL PERMEABILITY TYPHOID FEVER VACCINE

Contacts and locations

Locations

USDA, ARS, Western Human Nutrition Research Center

Davis, California, 95616, United States

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