A creatina como suplemento ergogênico para atletas

Novel renal biomarkers show that creatine supplementation is safe: a double-blind, placebo-controlled randomized clinical trial

The aim of this study was to evaluate the impact of creatine supplementation (CS) on renal function in young, healthy, and active subjects. We used a randomized, double-blind, placebo-controlled clinical trial as the study design. Thirty-six healthy male university students were recruited and divided into three groups: group placebo, group G3 (3 g/day of CS), and group G5 (5 g/day of CS). To assess renal function, new kidney biomarkers, kidney injury molecule-1 (KIM-1) and monocyte chemoattractant protein-1 (MCP-1), were quantified. Serum albumin, serum creatinine, serum urea, estimated glomerular filtration rate (eGFR), proteinuria, and albuminuria were also measured. All groups were evaluated at two times: prior CS or placebo (pre) and after 35 days on CS or placebo (post). After 35 days of intervention, all characteristics were maintained without significant difference (P > 0.05) between the groups, including serum creatinine, eGFR, and more sensitive kidney biomarker concentrations (KIM-1 and MCP-1). The paired analysis showed that the supplemented groups (G3 and 5G) had increased serum creatinine and decreased eGFR levels (P < 0.05). However, the values were still within the normal reference range. In conclusion, the results of renal function evaluation did not show any difference between the evaluated groups. Increased serum creatinine and decreased eGFR levels in CS groups can be explained by increased creatine stores and metabolism, since creatinine is a by-product of creatine metabolism. These findings indicate that the use of CS at doses of 3 g and 5 g/day for a short period (35 days) is safe and did not impair the kidneys or renal function in young healthy subjects.

Efeitos do flavonóide quercetina e dos corantes bixina e norbixina sobre parâmetros sanguíneos de coelhos

Avaliou-se a ação terapêutica da quercetina, bixina e norbixina, na dose diária de 0,01mol/kg, em coelhos hiperlipidêmicos induzidos por colesterol a 0,5% e ácido cólico a 0,1%, durante o período de vinte e oito dias, após o qual foram dosados colesterol, colesterol-HDL, triacilgliceróis, uréia, creatinina, ácido úrico, proteínas totais, cálcio, aspartato aminotransferase e alanina aminotransferase. Estes estudos são importante para se verificarem os efeitos de flavonóides e corantes sobre o metabolismo destas substâncias, permitindo a interpretação de desordens hepáticas ou renais. Os resultados mostraram que os teores de colesterol foram menores para os animais tratados com bixina (-4,03%) e quercetina (-35,07%), enquanto sua associação reduziu o nível de uréia em 5,73%. Nenhuma das substâncias testadas apresentou efeitos deletérios, todavia, não é possível demonstrar a inocuidade destes compostos.