Effect of Creatine Supplementation on Physical Performance in Vegan Subjects

This randomized, double-blind, placebo-controlled clinical study aims to evaluate the effect of creatine monohydrate supplementation on body composition, physical performance, and plasma biomarkers in 20 vegan individuals (10 men and 10 women) over a 4-week period. Participants, who will have followed a strict vegan diet for at least 6 months prior to the study's start, will be randomly assigned to one of two groups: one receiving 0.1 grams of creatine monohydrate daily and the other receiving a placebo (maltodextrin). A dietitian-nutritionist will standardize the participants' diet to ensure it is normocaloric and equivalent in macronutrient distribution. To ensure proper dietary control, 3-day dietary records (two weekdays and one weekend day) will be maintained both at the start of the study and during the last week of the intervention.

Assessments will be conducted before the start of the study (week 0) and at the end (week 4), and will include body composition measurements using the InBody system, physical tests (30-meter sprint, dynamometry, countermovement jump (CMJ), maximum isometric force, and a 15-repeated-jumps test), as well as blood analyses for creatine, creatinine, and creatine kinase (CK) levels, and urine analyses for creatine excretion. It is expected that creatine supplementation in vegan subjects will significantly increase lean muscle mass, improve physical performance in the mentioned tests, and elevate muscle creatine levels while decreasing markers of muscle damage (CK). Statistical analysis will include a repeated measures ANOVA to evaluate changes in dependent variables between groups over time, with a significance level set at p < 0.05.

Inclusion criteria

• Vegan diet for at least 6 months prior to the study's start.
• Aged between 18-40 years.
• Physically active according to the recommendations of the World Health Organization (WHO).
• Body Mass Index (BMI) between 18.5-24.9 kg/m2.
• No tobacco use.
• No or low alcohol consumption and no orthopedic limitations that would interfere with the performance of the study tests.

Exclusion criteria

• Chronic diseases that impair athletic performance (cardiovascular, metabolic, gastrointestinal, respiratory) within the last six months.
• Musculoskeletal disease within the last six months.
• Creatine supplementation prior to the study's start