Relationship between relative skeletal muscle index (RSMI) in physically active adults and the use of major sports supplements: a retrospective observational study

Abstract

Introduction: The indiscriminate use of supplements poses a problem for overall health, with Brazil being one of the countries that consumes the most dietary supplements in the world. However, when used as indicated and correctly, supplements can positively influence muscle mass gain, performance, and general health. Objective: This study aimed to evaluate whether there is a relationship between physical exercise and the use of supplements related to physical exercise that are most common in clinical practice (whey protein, creatine, hydroxymethylbutyrate, beta- alanine, glutamine, and caffeine) with relative skeletal muscle indices (RSMI). Methods: The present study employed a retrospective observational design, adhering to the STROBE guidelines. A total of 50 adult patients aged between 18 and 65 years who practice physical exercise were evaluated in medical centers in the city of Brasília between May 2023 and May 2024 using whole-body Bioimpedance Imaging or DEXA analysis. Only patients who used one or more supplements and were non-sedentary according to the criteria of the health organization were included in the study. Results: The general clinical data presented a total of 50 participants, the majority of whom were male (58%), with the DEXA group having 44 participants and the BIO group having 06 participants. The overall mean age was 40.60 years (22 to 60). The amount of physical exercises practiced per week was 4.80 (3 to 9) in general. It was also found that the overall RSMI had a mean of 8.56 ±1.76. The general use of supplements (DEXA and BIO) showed that the use of creatine (34%) and creatine with Whey Protein (24%) were the most frequent. The present study observed that there was an important relationship between the male gender and the RSMI, with OR=4.89 and p=0.000. In addition, the nominal logistic regression analysis of the supplement predictors in general (DEXA and BIO) to the RSMI response predictor showed statistical significance to the combinations of supplements creatine, BCAA, Whey, and Whey, creatine, and beta-alanine, p=0.015 and OR=1.62 for both combinations. There was no statistically significant difference between the mean RSMI values of the DEXA and BIO groups, with p=0.307. Conclusion: It was concluded that there was a relationship between physical exercise and the use of supplements most common in clinical practice, such as Whey protein, creatine, hydroxymethylbutyrate, beta-alanine, glutamine, and caffeine with the increase in the relative skeletal muscle mass index (RSMI) in physically active adults. The general use of supplements (DEXA and BIO) showed that the use of creatine (34%) and creatine with Whey Protein (24%) were the most frequent. Furthermore, there was an important relationship between the male gender and the relative skeletal muscle index (RSMI). In the female gender, no increase was observed. Statistical significance was evidenced by the combinations of supplements creatine, branched-chain amino acids (BCAA), Whey, and Whey, creatine, and beta-alanine. There was no statistically significant difference between the mean RSMI values of the DEXA and BIO group