Summary Longitudinal beta-alanine (BA) supplementation can improve exercise performance in males through increases in carnosine; however, females experience greater relative increases in carnosine compared to males. This potentially allows females to benefit from acute BA doses; however, effects of an acute BA dose on performance in females remain unknown. The purpose of this investigation was to evaluate how an acute dose of 1.6 g BA affects anaerobic performance in female cyclists. Twelve females (age526.661.3 y) volunteered to participate in this randomized, double-blind study. All participants completed two supplement trials: 1) Placebo534 g dextrose and 2) BA51.6 g BA 1 34 g dextrose. Thirtyminutes after supplementation, participants performed three repeated Wingate cycling tests with 2 min of active rest after each. Fatigue index, mean power, and peak power were measured during each Wingate. Lactate, heart rate, and rating of perceived exertion (RPE) were measured at rest, immediately after each Wingate, and after each active rest period. RPE significantly decreased (p,0.001) immediately following Wingates 1 and 2 and after each 2-min rest period for the BA trials; however, no differences were observed immediately after Wingate 3 (p.0.05). No significant supplementation effect was observed for any performance or physiological variable (p.0.05 for all variables). Findings suggest that an acute dose of BA (1.6 g) decreases RPE during anaerobic power activities in trained female cyclists.
In the US, one in every three children ages 2‐19 is overweight or obese. Although multifactorial in nature, obesity is primarily attributed to a mismatch between energy intake and energy expenditure (EE). One factor that influences this balance is thermic effect of food (TEF). Diets higher in protein have been shown to increase TEF. Breakfast is a key component of a healthy diet and can positively impact children’s health. It has been suggested that skipping breakfast may lead to greater hunger later in the day, resulting in greater overeating. The objective of this study was to determine if an egg/protein (PRO)‐based breakfast (22% PRO, 48% carbohydrate (CHO), 30% fat) would enhance TE, improve glycemic control and reduce hunger in NW (n=14) and OW (n=11) school‐aged children compared to an isocaloric CHO‐based breakfast (5% PRO, 65% CHO, 30% fat). Twenty‐three children (8‐12 y) completed both the PRO and CHO breakfast trials. EE was determined via indirect calorimetry at 0, 30, 60, 120, and 240 min postprandial (PP). Blood glucose (BG) was collected at 0, 15, 30, 60, 120, and 240 min PP and levels of hunger were assessed using a visual analog scale at same interval. At 240 min, an ad libitum buffet lunch was provided. Results indicate no significant difference in PP BG values between groups. However, PRO significantly reduced PP hunger (p<0.05) compared to CHO in NW and OW children. Consumption of PRO resulted in lower caloric intake at lunch (~100 kcal) compared to CHO. Relative to body weight, NW burn more calories per min compared to OW. NW have significantly higher TEF compared to OW (CHO p<0.001, PRO p=0.001). There was a trend (p=0.068) for higher TEF (10%) with PRO compared to CHO in OW. These data suggest that consumption of a PRO‐based breakfast has the potential to modulate PP energy metabolism in OW children through increased TEF, improved BG regulation, and decreased hunger.
Grant Funding Source: Supported by the American Egg Board/Egg Nutrition Center.
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