Karpouzi C, Kosmidis I, Petridou A, Virgiliou C, Gika H, Theodoridis G, Bogdanis GC, Mougios V (2023). EFFECTS OF PROTEIN SUPPLEMENTATION, COMBINED WITH HIGH-INTENSITY FUNCTIONAL TRAINING, ON THE PLASMA AMINO ACID PROFILE, BIOCHEMICAL AND HEMATOLOGICAL PARAMETERS IN TRAINED MEN AND WOMEN

INTRODUCTION: High-intensity functional training (HIFT) is an effective form of training that includes multijoint aerobic and resistance exercises. Despite its popularity, few studies have examined adaptations to HIFT and even less is known regarding dietary guidelines to optimize HIFT. Protein supplementation has been extensively investigated in resistance training, but there is limited evidence regarding its effectiveness in HIFT. Additionally, few studies have examined egg white as a protein source. Hence, the aim of this study was to examine the effects of two forms of protein supplementation (egg white and whey), combined with HIFT, on the plasma amino acid profile, biochemical and hematological parameters of trained individuals.

METHODS: Thirty trained volunteers (20 men and 10 women), aged 23-55, underwent 6 weeks of HIFT while receiving 0.6 g/kg/day of egg white protein (E), whey protein (W), or maltodextrin (placebo, P) in a single-blinded, randomized, triple-crossover, and counterbalanced design, with 2 weeks of washout between supplements. Participants received isoenergetic dietary plans providing 1 g/kg/day of protein throughout the study. Before and after each intervention period, participants provided fasting venous blood samples at rest. Full blood count, serum glucose, triacylglycerols, total cholesterol (TC), HDL cholesterol, LDL cholesterol, urea, creatinine, creatine kinase, γ-glutamyltransferase, cortisol and testosterone were measured in automated analyzers. Plasma amino acids were measured with liquid chromatography – mass spectrometry. Data were analyzed by 3-way ANOVA (supplement x time x sex) with repeated measures on supplement and time. Statistical significance was set at p < 0.05. RESULTS: Urea and TC differed between supplements, with urea being higher in E and W, compared to P, and TC being higher in P compared to W. Leukocyte and platelet counts increased, whereas erythrocyte count, hemoglobin, hematocrit and glucose decreased with training. There were also expected differences between sexes in hematologic and biochemical parameters. Regarding the plasma amino acid concentrations and percentage distribution, there were no differences between supplements. However, there were many effects of training (including increases in Leu, Pro and Trp, and decreases in Arg, Asn, Gln, Gly and Lys, in terms of both concentration and percentage) and differences between sexes, including a higher total plasma amino acid concentration in men compared to women (2.57 ± 0.50 vs 2.35 ± 0.46 mmol/L, mean ± SD).

CONCLUSION: Short-term HIFT caused several changes in hematologic and clinical-chemistry parameters of trained men and women (notably hemodilution), whereas protein supplementation affected only serum, urea and TC. Additionally, training, but not supplementation, had profound effects on the plasma amino acid profile. These novel findings show that training is a stronger modifier of blood biochemistry and, in particular, amino acid metabolism than nutrition.

Η υποψήφια διδάκτορας Χριστίνα Καρπούζη κέρδισε ένα από τα τρία Young Scholar Travel Grant Awards που αθλοθέτησε το Gatorade Sport Science Institute στο πλαίσιο του 28ου Συνεδρίου του European College of Sport Science στο Παρίσι