[Sugary drinks and glycemia]. / Bebidas açucaradas e glicémia.

Obesity prevalence is increasing all over the world. Most affected are people changing from a traditional lifestyle to an environment with both availability of high energy diet and less physical activity. Glycemic index (GI) is a measure of dietary glycemic carbohydrates, representing their ability to raise blood glucose concentrations. It refers to the postprandial blood glucose response expressed as a percentage of the response to a reference food (glucose or white bread) containing the same carbohydrate content. Given the present high consumption of sugary drinks, the putative contribution of these products to obesity deserves investigation. The aim of this study was to determine the GI of some drinks from the Portuguese market. Postprandial glycemia after ingestion of apple Frutis, peach Frutis, Green tea Frutea, green tea, black tea, lupin infusion, rooibos infusion, raftilose solution or bran solution has been determined for two hours in a caucasian population of young adults of any sex, 17 to 24 years of age. Apple Frutis GI was found to be 54.3, i.e., a low GI; Frutea Green tea had a GI of 64.7, considered as a moderate GI; peach Frutis showed a high GI, 86.6. Green and Black teas as well as rooibos and lupin infusions, all with added glucose (25 g), did not change glycemic response in comparison with the reference solution (water with 25 g glucose). No differences were seen after raftilose and bran solutions by comparison with the reference solution. GI information may help the choice of carbohydrates to include in a healthy diet. Formerly considered as a parameter of interest to diabetic patients, it may actually interest anybody concerned with a healthy diet. This study has been performed by medical and nutritional science students, who observed glycemic excursions in themselves, after drink ingestion. This experiment allowed them to see the impressive rise of glycemia after ingestion of a sugary drink, by comparison with basal levels which would not rise if plain water or other nonsugary drink had been ingested.

[Impact of acute exercise intensity on plasma concentrations of insulin, growth hormone and somatostatin]. / Exercício físico e insulina, hormona do crescimento e somatostatina.

Obesity is increasing all over the world, its morbidity justifying a serious effort to improve the situation. Diet and physical exercise constitute major measures to fight obesity. We aimed to investigate the effect of acute exercise intensity over plasma insulin, growth hormone and somatostatin responses. Plasma levels of insulin, growth hormone, somatostatin and glucose were measured at baseline, after 15 minutes of moderate intensity exercise and after 15 minutes of high intensity exercise in a group of young healthy volunteers. Insulin, growth hormone and somatostatin were measured by immunoradioassay and glucose by a glucose oxidase method. After moderate intensity exercise plasma insulin levels tended to decrease, growth hormone tended to increase and somatostatin did not change. A similar period of high intensity exercise led to a similar decrease of plasma insulin, a much higher increase of growth hormone plasma level and no change of somatostatin. Glycemia suffered no significant change throughout the experiment. We conclude that hormonal changes induced by physical exercise depend on the intensity of exercise. When comparing moderate with high intensity exercise, a similar response of plasma insulin and a lower growth hormone/somatostatin ratio may support a healthier cardiovascular effect for moderate intensity exercise.