Beta-alanine fails to improve on 5000 m running time despite increasing PAT1 expression in long-distance runners.

BACKGROUND: Beta-alanine has become a dietary supplement widely used by athletes due to its ergogenic effect. However, there is still no consensus on the performance benefit of beta-alanine on exercise lasting longer than ten minutes. The present study aimed to evaluate the effect of beta-alanine supplementation on running performance and the expression of TauT and PAT1. METHODS: This double-blind, randomized study enrolled 16 long-distance runners (37±8 years) who were randomly allocated to two groups: placebo (PLA) and beta-alanine (BA) (4.8 g/day 1) for four weeks. Maximal oxygen consumption, anthropometry, body composition, and food intake were determined. Before and after the intervention, the athletes undertook a 5000 m running time trial. Venous blood (TauT and PAT1 expressions) and ear lobe capillary blood (lactate) collected before and after exercise. Between tests, we monitored the training variables. RESULTS: The results were analyzed by t-tests and an ANOVA of repeated measures, with Sidak's post hoc (P<0.05). PLA exhibited lower body fat than BA (8.7±2.2 vs. 11.5±2.8%, P=0.04). After supplementation, there was an increase in PAT1 expression in BA when compared to PLA (1.17±0.47 vs. 0.77±0.18, P=0.04). No significant differences were shown for the 5000 m running time in PLA (PRE: 1128±72; POST: 1123±72s) and BA (PRE: 1107±95; POST: 1093±86s). CONCLUSIONS: Although beta-alanine supplementation increased PAT1 expression, there was no statistically significant improvement in 5000 m running performance. However, individual responses should be considered as the BA showed a higher delta than the PLA.

Green tea supplementation promotes leukocyte telomere length elongation in obese women.

INTRODUCTION: inflammation and oxidative stress are factors that may play a substantial role in telomere attrition. In line of this, obesity is associated with telomere shortening. Green tea had anti-inflammatory and antioxidant effects and may alter telomere length (TL). OBJECTIVES: we evaluated the effect of decaffeinated green tea supplementation in obese women on TL. METHODS: we conducted a cross-sectional interventional study with ten obese (body mass index [BMI] > 40 kg/m²) and eight normal weight (BMI > 18.5 and < 24.9 kg/m²) women (age between 27 and 48 years). The supplementation was carried out with capsules (each contained 450.7 mg of epigallocatechin-3-gallate) during eight weeks. Anthropometric and dietary intake assessment, and blood collection (for biochemical and TL analysis by quantitative PCR) were performed before and after supplementation. Normal weight patients were evaluated at a single moment. RESULTS: we observed a significant increase on TL after supplementation (1.57 ± 1.1 to 3.2 ± 2.1 T/Sratio; p < 0.05). Moreover, we found shorter TL in obese patients (day 0) when compared to normal weight individuals (3.2 ± 1.9 T/Sratio; p < 0.05) and an inverse association between TL and BMI, even after age adjustment (beta = -0.527; r² = 0.286; IC = -0.129, -0.009). CONCLUSION: obesity is related to shorter telomeres. Green tea supplementation during eight weeks promotes telomere elongation in obese women.

Effects of Short-Term Calcium Supplementation in Children and Adolescents with Phenylketonuria.

Reduction of bone mineral density and the risk of osteopenia have been reported to occur in phenylketonuria (PKU) patients. This study aimed to evaluate the short-term effects of calcium supplementation in phenylketonuric children and adolescents. The study included 18 patients with PKU aged 5-18 yr (61% male) under clinical and nutritional treatment. Evaluation of food intake, anthropometry, and biochemical and phalangeal quantitative ultrasound were performed before (phase 1) and after (phase 2) calcium supplementation (1000 mg/d) for 34 d. Statistical analysis was performed using t test for paired samples, Wilcoxon's test, and McNemar's test (p <0.05). There was an inadequate intake of phosphorus and vitamin D, the same occurring with serum concentrations of these nutrients. About 50% of the patients had an accumulation of adipose tissue measures, with a negative correlation between Z-score, body mass index, and phalangeal quantitative ultrasound (amplitude-dependent speed of sound [AD-SoS]). There was a significant difference in urinary phosphorus excretion with higher values before supplementation. Comparison of the two phases revealed significantly higher AD-SoS values after the supplementation (p = 0.017). The reduction in phosphorus excretion associated with increased AD-SoS between the two phases suggested increased bone formation, and showed no negative effects in relation to short-term calcium supplementation in children and in adolescents with PKU.