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

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.

Conditions

• Respiratory Tract Infections (RTI)
• Mucosal Immunity
• Systemic Inflammation
• Depressive Disorder
• Exercise-Induced Immunosuppression
• Athletic Performance
• Upper Respiratory Tract Symptoms
• Mental Health
• Cytokine Response
• Probiotic Therapy

Interventions

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.

Sponsors & Collaborators

• Federal University of São Paulo

  lead OTHER

Principal Investigators

• Cesar Miguel M dos Santos, PHD · Enau College

• Jonatas B do Amaral, PHD · Federal University of São Paulo

• André Luis L Bachi, PHD · Santo Amaro University

• Mauro W Vaisberg, PHD · Federal University of São Paulo

Study Design

Allocation

RANDOMIZED

Purpose

PREVENTION

Masking

QUADRUPLE

Model

PARALLEL

Eligibility

Min Age

25 Years

Max Age

45 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2025-08-13

Primary Completion

2025-08-21

Completion

2025-11-05

Countries

• Brazil

Study Locations