EFFECTS OF PROTEIN SUPPLEMENTS ON LIVER ENZYMES LEVELS IN ATHLETES
Keywords:
protein supplements, training, liver enzymes, athletesAbstract
Athletes have an increased physiological need for protein, which they satisfy by taking various synthetic
supplements. Although numerous benefits of protein supplementation are known, the purpose of this study is to
investigate whether serum levels of liver enzymes (alanine aminotransferase, aspartate aminotransferase, gammaglutamyl
transferase, and lactate dehydrogenase) decrease in athletes after a seven-day break from protein intake.
The study was designed as a cohort, longitudinal, and intervention study. It was conducted at the Department of
Medical-Biochemical Diagnostics, Atrijum Sarajevo Polyclinic, after approval by the Ethics Committee of the
Faculty of Health Studies and the health facility. In the study, 190 subjects were divided into groups based on their
professional status, supplement use, training duration, and type of exercise. The personal data of the subjects were
protected according to the principles of the Declaration of Helsinki. Spectrophotometric determination of liver
enzymes was performed using a Mindray BS 480 biochemical analyzer. Descriptive and inferential statistical tests
were used for statistical analysis, and the p-value was set at the conventional level of 0.05. According to the results
of the study, the average age of the subjects in the control group was 27.9 years, while in the studied groups it was
34.8, 35.1, and 19.8 years, respectively. At the first measurement, the highest mean values of alanine
aminotransferase (74.83 U/L), gamma-glutamyl transferase (26.43 U/L), and lactate dehydrogenase (421.56 U/L)
were obtained in the group of subjects with low-intensity training and protein supplementation, and aspartate
aminotransferase (56.83 U/L) in the group with high-intensity training and supplementation. After a seven-day break
from supplementation, a greater decrease in alanine aminotransferase (57.96%), aspartate aminotransferase
(59.58%), and lactate dehydrogenase (3.37%) was found in the group with high-intensity training. A greater
decrease in gamma-glutamyl transferase (18.31%) was registered in the low-intensity training group. A statistically
significant difference was found between the studied groups at the level of p <0.05 for all studied variables. From
the above results, it can be concluded that the use of protein supplements is an independent predictor of short-term
liver load reflected in increased values of liver enzymes in athletes. A significant decrease in the levels of most liver
enzymes after short-term interruption of supplementation indicates the onset of hepatocyte regeneration. Insufficient
education about the importance of establishing a nutritional plan and an expert, individualized supplementation
program for athletes based on laboratory test results is a major problem in our country. More research is needed to
provide relevant and detailed information on the effects of protein supplementation not only on the liver but also on
the entire metabolic system.
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