The Effects of Probiotic Supplementation on Performance, Body composition, Gastro- intestinal Symptoms and Mood Status in Unprofessional Athletes: Study Protocol for a Randomized Double-blind Clinical Trial

Background: Probiotic supplementation has emerged as a promising strategy in sport nutrition, with potential benefits for various aspects of athletes' health and performance. The study aims to explore the impact of probiotic supplementation on performance, body composition, gastrointestinal symptoms, and mood status in non-elite athletes. Methods/Design: In this double-blind, randomized controlled clinical trial, 36 non-elite athletes were randomly assigned to receive a probiotic supplement (containing 2×10 ⁹ colony-forming units Lactobacillus acidophilus, Lactobacillus plantarum, Lactobacillus paracasei) or identical placebo once a day for 12 weeks. The body composition, muscle strength, and performance will be measured at baseline and following supplementation. The sociodemographic, physical activity and dietary intake questionnaires will be collected for each subject. Additional questionnaires will inquire about GI symptoms, and mood status at baseline and following treatment. The evaluation of primary and secondary outcomes will involve comparing results among intervention groups, considering baseline values. Discussion: By promoting a healthy balance of gut microbiota, probiotics may offer a natural and effective way to improve overall well-being and enhance various aspects of performance. This trial’s findings may be incorporated in to evidence-based guidelines that address the alternation of gut microbiota to enhance athletic performance. Ethics and dissemination: There are so far no reported adverse effects associated with the use of probiotic. The research has obtained approval from the Medical Ethics Committee at Tehran University of Medical Sciences in Iran ethical code: IR.TUMS.MEDICINE.REC.1403.157 Trial registration: IRCT20240424061562N1, registered on 30/7/2024. https://www.irct.ir/trial/77722.