Trials / Completed

CompletedNCT06970964

Fermented Milk Drink With Lacticaseibacillus Paracasei Strain Shirota Helps Triathletes With Cold-Like Symptoms Before and After a Race

A Multi-Center, Double-Blind, Randomized, Parallel Group Study to Evaluate the Effect of Fermented Milk Containing Lacticaseibacillus Paracasei Strain Shirota (LCS) on the Upper Airway Symptoms of Triathletes Both Before and After a Competition

Status: Completed
Phase: N/A
Study type: Interventional
Enrollment: 80 (actual)

Sponsor: Federal University of São Paulo · Academic / Other
Sex: All
Age: 25 Years – 45 Years
Healthy volunteers: Accepted

Summary

This study aims to evaluate whether a fermented milk drink containing the probiotic strain Lacticaseibacillus paracasei strain Shirota (LCS), commonly found in Yakult®, can help reduce upper respiratory symptoms in triathletes before and after competition. Athletes often experience cold-like symptoms due to physical stress, intense training, and immune system challenges. The study investigates whether daily consumption of this probiotic drink can help improve immune response and reduce the incidence or severity of symptoms such as sore throat, nasal congestion, or coughing. This is a randomized, double-blind, placebo-controlled, parallel-group study involving healthy adult triathletes. Participants will be randomly assigned to receive either the probiotic drink or a placebo for a specific period before and after a triathlon event. Symptoms and health markers will be tracked through questionnaires and biological samples. The goal is to explore whether probiotic supplementation can provide practical, non-pharmacological support for athletes' immune health and well-being during intense physical activity.

Detailed description

Background: Endurance athletes are frequently exposed to high physical stress, which may lead to temporary immune suppression and increased susceptibility to upper respiratory tract infections (URTIs). Previous studies suggest that probiotics may play a role in supporting the immune system. Objective: To assess the efficacy of a fermented milk drink containing Lacticaseibacillus paracasei strain Shirota (LCS) in reducing upper airway symptoms in triathletes before and after a competitive event. Study Design: This is a multi-center, double-blind, randomized, placebo-controlled, parallel-group study. Eligible participants will be healthy adult triathletes preparing for a scheduled race. They will be randomized to consume either the probiotic drink or a placebo daily, starting several weeks before the race and continuing for a defined recovery period afterward. Primary Outcome: -Salivary IgA Concentration The primary outcome is the change in salivary immunoglobulin A (IgA) concentration before and after the competition, assessed at five time points. This measure will reflect mucosal immune function and the potential modulatory effect of daily intake of fermented milk containing Lacticaseibacillus paracasei strain Shirota. Secondary Outcomes: * Systemic Immune and Inflammatory Response Blood samples will be analyzed for markers of systemic immune activation and inflammation (e.g., cytokines), collected at five time points to evaluate the broader immunomodulatory effects of the probiotic intervention. * Upper Airway Symptoms Incidence, severity, and duration of upper airway symptoms (e.g., sore throat, cough, nasal congestion) will be assessed using the Wisconsin Upper Respiratory Symptom Survey-21 (WURSS-21). Higher scores indicate more severe symptoms and a greater impact on daily functioning. * Mood State Mood state changes will be evaluated using the Brunel Mood Scale (BRUMS) across six subscales. Total Mood Disturbance (TMD) scores will reflect the psychological response to training and competition. Higher scores indicate worse mood states.

Conditions

Interventions

Type	Name	Description
DIETARY_SUPPLEMENT	Intervention Name: Fermented milk containing Lacticaseibacillus paracasei strain Shirota. Intervention Name: Non-fermented milk (placebo)	Participants will ingest 80 mL per day of fermented milk containing 40 billion colony-forming units (CFU) of Lacticaseibacillus paracasei strain Shirota (LcS), starting 30 days before a triathlon competition and continuing until 14 days post-race. The fermented milk is stored refrigerated and consumed once daily.
DIETARY_SUPPLEMENT	Non-fermented milk (placebo)	Participants will ingest 80 mL per day of non-fermented milk identical in taste, appearance, and packaging to the probiotic drink, but without Lacticaseibacillus paracasei strain Shirota. Administration follows the same schedule as the probiotic group.

Timeline

Start date: 2025-08-13
Primary completion: 2025-08-21
Completion: 2025-11-05
First posted: 2025-05-14
Last updated: 2026-01-15

Locations

1 site across 1 country: Brazil

Source: ClinicalTrials.gov record NCT06970964. Inclusion in this directory is not an endorsement.