Relaxation breathing improves human glycemic response.

OBJECTIVES: This study evaluated a simple relaxation breathing exercise for acute improvement of postprandial glycemic and insulinemic status. DESIGN: Healthy human subjects were randomized to control breathing (CB; n=13) or a relaxation breathing exercise (RB; n=13) that was repeated every 10 minutes for the 30 minutes before and 90 minutes after consuming a glucose challenge (oral glucose tolerance test; OGTT; 75 g/240 mL). Blood samples were collected before, and 30, 60, and 90 minutes post OGTT for glucose and insulin analysis. RESULTS: Blood glucose at 0 minutes (pre-OGTT), and 30, 60, and 90 minutes post-OGTT with continued RB was 93.7±1.9, 136.5±8.1, 165.7±8.1, and 130.2±6.9 mg/dL, and 97.1±2.4, 173.1±8.4, 158.7±11.1, and 137.1±10.1 with CB, respectively. RB blood glucose was significantly lower at 30 minutes than CB. Glucose area under the curve (AUC) for CB and RB were not significantly different. Plasma insulin for both CB and RB was significantly increased relative to baseline at 30, 60, and 90 minutes. Insulin values for RB tended to be higher than CB at 30 and 60 minutes, although the difference was not statistically significant. Insulin AUC for CB and RB was not significantly different. CONCLUSIONS: Relaxation breathing acutely improves the glycemic response of healthy subjects, and breathing pattern could be important for interpretation of glycemic index measurements.

Effect of Red Bull energy drink on cardiovascular and renal function.

Energy drink consumption has been anecdotally linked to the development of adverse cardiovascular effects in consumers, although clinical trials to support this link are lacking. The effects of Red Bull energy drink on cardiovascular and neurologic functions were examined in college-aged students enrolled at Winona State University. In a double-blind experiment where normal calorie and low calorie Red Bull were compared to normal and low calorie placebos, no changes in overall cardiovascular function nor blood glucose (mg/dL) were recorded in any participant (n = 68) throughout a 2-h test period. However, in the second experiment, nine male and twelve female participants subjected to a cold pressor test (CPT) before and after Red Bull consumption showed a significant increase in blood sugar levels pre- and post Red Bull consumption. There was a significant increase in diastolic blood pressure of the male volunteers immediately after submersion of the hand in the 5 degrees C water for the CPT. Under the influence of Red Bull, the increase in diastolic pressure for the male participants during the CPT was negated. There were no significant changes in the blood pressure of the female participants for the CPT with or without Red Bull. Finally, the CPT was used to evaluate pain threshold and pain tolerance before and after Red Bull consumption. Red Bull consumption was associated with a significant increase in pain tolerance in all participants. These findings suggest that Red Bull consumption ameliorates changes in blood pressure during stressful experiences and increases the participants' pain tolerance.

Human glycemic response and phenolic content of unsweetened cranberry juice.

This cross-sectional study determined the phenolic composition of an over-the-counter cranberry juice (CBJ) with high-performance liquid chromatography and examined the effects of low- and normal-calorie CBJ formulations on the postprandial glycemic response in healthy humans. The CBJ used in this study contained seven phenolic acids, with 3- and 5-caffeoylquinic acid being the primary components, and 15 flavonol glycosides, with myricetin-3-galactoside and quercetin-3-galactoside being the most prevalent. CBJ proanthocyanidins consisted of three different tetramers and a heptamer, which were confirmed with matrix-assisted laser desorption ionization-time of flight-mass spectrometry analysis. Participants received one of the following six treatments: nothing (no water/beverage), water (480 mL), unsweetened low-calorie CBJ (38 Cal/480 mL), normal-calorie CBJ (280 Cal/480 mL), isocaloric normal calorie (high fructose corn syrup [HFCS]), or isocaloric low-calorie beverages. No significant differences in postprandial blood glucose or insulin were observed in the groups receiving nothing, water, or low-calorie treatments. In contrast, the ingestion of normal-calorie CBJ and normal-calorie control beverage resulted in significantly higher blood glucose concentrations 30 minutes postprandially, although the differences were no longer significant after 180 minutes. Plasma insulin of normal-calorie CBJ and control (HFCS) recipients was significantly higher 60 minutes postprandially, but not significantly different 120 minutes postprandially. CBJ ingestion did not affect heart rate or blood pressure. This study suggests that the consumption of a low-calorie CBJ rich in previously uncharacterized trimer and heptamer proanthocyanidins is associated with a favorable glycemic response and may be beneficial for persons with impaired glucose tolerance.