Effects of taurine supplementation in elite swimmers performance

AIM: Taurine is considered a semi-essential amino acid characterized by having various physiological functions in the body that modulate mechanisms of action involved in the muscle contraction process, increased energy expenditure, insulin signaling pathway, carbohydrate metabolism, and scavenging free radicals. These functions are crucial for aerobic exercise performance; thus, taurine supplementation may benefit athletes' performance. The objective of this study was to evaluate the effects of taurine supplementation on the resting energy expenditure and physical performance of swimming athletes. METHODS: In a double-blind study, 14 male swimmers were randomized into two groups: the taurine group (n = 7) and the placebo group (n = 7), which received 3 g per day of taurine or placebo in capsules during 8 weeks. Resting energy expenditure, plasma taurine, physical performance, anthropometry, dietary consumption were measured and an incremental test was performed to determine their maximal front crawl swimming performances before and after the 8-week period. RESULTS: The levels of serum taurine (p < 0.0001) and lactate (p = 0.0130) showed a significant increase in the taurine group; however, the other variables were not different. No changes were observed in the resting energy expenditure, mean speed performed, and the anaerobic threshold of the swimmers post-supplementation period. CONCLUSION: Supplementation of taurine increased plasma concentrations of this amino acid, but did not lead to significant changes in food intake, rest energy expenditure, and athletes' performance. However, the supplemented group presented a higher lactate production, suggesting a possible positive effect of taurine on the anaerobic lactic metabolism.(AU)

Estimativa da ingestão de ferro e vitamina C em adolescentes no ciclo menstrual / Estimate of iron and vitamin C intake in adolescents during the menstrual cycle phases

Avaliou-se o nível de ingestão de ferro e vitamina C, em adolescente nas três fases do ciclo menstrual. O consumo alimentar de trinta adolescentes foi analisado pela técnica de registro, durante as fases pré-menstrual, menstrual e pós-menstrual, com a análise de dois registros por indivíduo, em cada fase. A prevalência da ingestão foi feita considerando seis registros alimentares de cada adolescente. Os padrões utilizados como referência foram as Dietary Reference Intakes (DRI)- Estimated Average Requirement (EAR) do Institute of Medicine (IOM), utilizando as abordagens probabilística e ponto de corte, para o ferro e vitamina C, respectivamente, além dos valores do Recommended Dietary Allowances (National Research Council). As adolescentes tinham 15,5 ± 1,7 anos, com idade da menarca de 11,8 ± 1,1 anos e ginecológica de 3,6 ± 1,9 anos. O consumo mediano de ferro foi 10,6 mg/dia e de vitamina C, 77,6 mg/dia. Observou-se pelas DRI-EAR uma prevalência de inadequação para ferro de 22,6 por cento e de vitamina C 34 por cento e pelo National Research Council, de 63,3 por cento e 20 por cento, respectivamente. Apesar da divergência entre os padrões, os resultados apontam risco nutricional para a população estudada. Sugere-se a realização de mais estudos dietéticos, utilizando as DRI-EAR, favorecendo diagnósticos nutricionais com subsequente medidas de intervenção.

The vitamin C and iron ingestion level was evaluated in adolescents during the three phases of the menstrual cycle. The food intake of 30 adolescents was analyzed during the premenstrual, menstrual, and postmenstrual phases, by the registration technique, with the analysis of two registrations per individual, in each phase. The prevalence estimate was done considering six dietary registrations for each adolescent. The patterns used as reference were the Dietary Reference Intakes (DRI) - Estimated Average Requirement (EAR) from Institute of Medicine - IOM (2001), using the probability approaches and the cut - point method for the iron and vitamin C respectively, in addition to the values from the Recommended Dietary Allowances (National Research Council). The adolescents were aged 15.5 ± 1.7; the age of the menarche was 11.8 ± 1,1; and gynecological age 3.6 ± 1.9. The medial consumption of iron was 10.6 mg/day and of vitamin C 77.6 mg/day. It was observed by DRIs-EAR an estimate of inadequacy for iron of 22.6 percent and for vitamin C of 34 percent and by National Research Council, 63.3 percent and 20 percent, respectively. Despite the divergence among the patterns, both results shows a nutritional risk for the studied population. The accomplishment of wider dietary studies, using DRI-EAR is suggested, favoring nutritional diagnoses with subsequent evaluation of intervention measures.