Gender impacts the post-exercise substrate and endocrine response in trained runners

<p>Abstract</p> <p>Background</p> <p>Although several studies have investigated gender differences in the substrate and endocrine responses during and following endurance exercise, few have studied sex differences during a more prolonged recovery period post endurance exercise. The purpose of this study was to compare and characterize the endocrine and substrate profiles of trained male and female adult runners during the three-and-a-half hour recovery period from an endurance run.</p> <p>Methods</p> <p>After consuming a euenergetic diet (1.8 g·kg^-1·d^-1protein, 26% fat, 58% carbohydrates, 42.8 ± 1.2 kcal/kg body weight) for 8 days, blood was collected from trained male (n = 6, 21 yrs, 70 kg, 180 cm, 9% body fat, VO_2peak78.0 ± 3.4 mL·kg FFM^-1·min^-1) and female (n = 6, 23 y, 66 kg, 170 cm, 29% body fat, VO_2peak71.6 ± 4.5 mL·kg FFM^-1·min^-1) endurance runners at rest and during recovery from a 75 min run at 70% VO_2peak. Circulating levels of glucose, lactate, free fatty acids (FFAs), insulin, cortisol, growth hormone (GH), and free insulin-like growth factor I (IGF-I) were measured.</p> <p>Results</p> <p>During the recovery period, females experienced increases in glucose, lactate and insulin while no changes were noted in men (<it>P </it>< 0.05). Males experienced increases in GH and decreases in IGF-I levels respectively (<it>P </it>< 0.05) while no changes were observed in females. FFA levels increased during recovery from endurance exercise, but changes were not different between genders.</p> <p>Conclusion</p> <p>These data further document gender differences in substrate and endocrine changes during a prolonged recovery period following endurance exercise. Future studies are needed to evaluate the effect of differing diets and nutritional supplements on these gender-specific post-exercise substrate and endocrine differences.</p

Aerobic fitness does not modulate protein metabolism in response to increased exercise: a controlled trial

© 2009 Smith et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens

High protein diet maintains glucose production during exercise-induced energy deficit: a controlled trial

<p>Abstract</p> <p>Background</p> <p>Inadequate energy intake induces changes in endogenous glucose production (GP) to preserve muscle mass. Whether addition provision of dietary protein modulates GP response to energy deficit is unclear. The objective was to determine whether exercise-induced energy deficit effects on glucose metabolism are mitigated by increased dietary protein.</p> <p>Methods</p> <p>Nineteen men ([mean ± SD] 23 ± 2 y, VO_2peak59 ± 5 ml·kg^-1·min^-1) were divided into three groups, two consuming moderate (MP; 0.9 g protein kg^-1d^-1), and one high (HP; 1.8 g protein kg^-1d^-1) protein diets (55% energy from carbohydrate) for 11 days. Following 4 days of energy balance (D1-4), energy expenditure was increased for 7 days (D5-12) in all groups. Energy intake was unchanged in two, creating a 1000 kcal d^-1deficit (DEF-MP, DEF-HP; n = 6, both groups), whereas energy balance was maintained in the third (BAL-MP, n = 7). Biochemical markers of substrate metabolism were measured during fasting rest on D4 and D12, as were GP and contribution of gluconeogenesis to endogenous glucose production (<it>f</it>_gng) using 4-h primed, continuous infusions of [6,6-²H₂]glucose (dilution-method) and [2-¹³C]glycerol (MIDA technique). Glycogen breakdown (GB) was derived from GP and <it>f</it>_gng.</p> <p>Results</p> <p>Plasma β-hydroxybutyrate levels increased, and plasma glucose and insulin declined from D4 to D12, regardless of group. DEF-MP experienced decreased plasma GP from D4 to D12 ([mean change ± SD] 0.24 ± 0.24 mg·kg^-1·min^-1), due to reduced GB from D4 (1.40 ± 0.28 mg·kg^-1·min^-1) to D12 (1.16 ± 0.17 mg·kg^-1·min^-1), P < 0.05. Conversely, BAL-MP and DEF-HP sustained GP from D4 to D12 ([mean change ± SD] 0.1 ± 0.5 and 0.0 ± 0.2 mg·kg^-1·min^-1, respectively) by maintaining GB.</p> <p>Conclusion</p> <p>Exercise-induced energy deficit decreased GP and additional dietary protein mitigated that effect.</p

Level of dietary protein intake affects glucose turnover in endurance-trained men

<p>Abstract</p> <p>Background</p> <p>To examine the effects of higher-protein diets on endogenous glucose metabolism in healthy, physically active adults, glucose turnover was assessed in five endurance-trained men (age 21.3 ± 0.3 y, VO_2peak70.6 ± 0.1 mL kg^-1min^-1) who consumed dietary protein intakes spanning the current dietary reference intakes.</p> <p>Findings</p> <p>Using a randomized, crossover design, volunteers consumed 4 week eucaloric diets providing either a low (0.8 g kg^-1d^-1; LP), moderate (1.8 g kg^-1d^-1; MP), or high (3.6 g kg^-1d^-1; HP) level of dietary protein. Glucose turnover (Ra, glucose rate of appearance; and Rd glucose rate of disappearance) was assessed under fasted, resting conditions using primed, constant infusions of [6,6-²H₂] glucose. Glucose Ra and Rd (mg kg^-1min^-1) were higher for MP (2.8 ± 0.1 and 2.7 ± 0.1) compared to HP (2.4 ± 0.1 and 2.3 ± 0.2, <it>P </it>< 0.05) and LP (2.3 ± 0.1 and 2.2 ± 0.1, <it>P </it>< 0.01) diets. Glucose levels (mmol/L) were not different (<it>P </it>> 0.05) between LP (4.6 ± 0.1), MP (4.8 ± 0.1), and HP (4.7 ± 0.1) diets.</p> <p>Conclusions</p> <p>Level of protein consumption influenced resting glucose turnover in endurance athletes in a state of energy balance with a higher rate of turnover noted for a protein intake of 1.8 g kg^-1d^-1. Findings suggest that consumption of protein in excess of the recommended dietary allowance but within the current acceptable macronutrient distribution range may contribute to the regulation of blood glucose when carbohydrate intake is reduced by serving as a gluconeogenic substrate in endurance-trained men.</p

Skeletal muscle protein turnover in runners and endurance-trained adults consuming the RDA for protein

Dietary protein needs of physically active individuals are a highly debated topic. However, the relationship between endurance exercise, protein intake, and skeletal muscle protein metabolism has received little attention in the scientific literature. This investigation consists of two studies which provide insight to this area. In the first investigation, five male runners participated in a randomized, crossover design diet intervention, where they consumed either a low (0.8 g/kg; LP), moderate (1.8 g/kg; MP), or high (3.6 g/kg; HP) protein diet for 4 weeks. Diets were isocaloric, with carbohydrate, fat and protein approximating 60%, 30%, 10%; 55%, 30%, 15; and 40%, 30%, 30% for LP, MP, and HP respectively. Mixed muscle protein fractional synthetic and breakdown rates (FSR/FBR) were assessed at week 4 following a 75 min run at 70% VO2peak using primed continuous infusions of [2H5]phenylalanine (FSR) and [15N]phenylalanine (FBR). Postexercise FSR was significantly higher for LP and MP compared to HP. Preliminary findings demonstrated a trend for postexercise FBR to decrease with increasing protein intake, thereby resulting in a less negative NET balance (FSR-FBR). This is the first study to demonstrate that dietary protein intake can impact protein utilization postexercise in the fasted state. ^ In the second study, the impact of 6-weeks of endurance training on FSR and FBR was examined in 12 untrained individuals fed eucaloric diets containing 0.8 g protein /kg/d. Subjects were divided into an egg and no egg group to examine the impact of protein source on protein utilization. Resting FSR and FBR significantly increased and NET balance became more negative (p \u3c 0.05) following 4 weeks of training (p \u3c 0.05). After a 45min run at 65% VO 2max, FBR significantly increased compared to rest (p \u3c 0.05). Consumption of the egg based diet did not significantly impact protein metabolism with the exception of the egg group demonstrating a significantly higher FBR postexercise compared to the no egg group (p \u3c 0.05). These findings are the first to demonstrate that routine endurance training significantly impacts skeletal muscle protein metabolism at rest and following a single exercise session. The impact of dietary protein source on these parameters was less clear and warrants further investigation.

Growth and Development of Preschool Children (12–60 Months): A Review of the Effect of Dairy Intake

Undernutrition in young children is a global health issue. The ability to meet energy and nutrient needs during this critical stage of development is necessary, not only to achieve physical and mental potential but also socio-economic achievement later in life. Given ongoing discussions regarding optimization of dietary patterns to support achievement of the Sustainable Development Goals established by the United Nations, it is important to identify foods/food groups that have shown efficacy in reducing the negative impacts of undernutrition in young children. This narrative review addresses the impact of dairy intake, with a focus on linear growth, cognitive development and weight gain in early childhood (12&ndash;60 months). The impact of country economic status is also examined, to help elucidate regional specific recommendations and/or future research needs. Overall, the body of research addressing this age group is somewhat limited. Based on the data available, there is a positive association between dairy intake and linear growth. The impact of milk or dairy products on cognitive development is less clear due to a lack of evidence and is a gap in the literature that should be addressed. Regarding the impact on body weight, the majority of evidence suggests there is either no association or an inverse association between milk intake by preschool children on overweight and obesity later in life. This evidence is exclusively in high income countries, however, so additional work in lower income countries may be warranted

Gender impacts the post-exercise substrate and endocrine response in trained runners-0

Ressed as mean ± SEM. REST, prior to exercise; POST+30, 30 min post-exercise; POST + 45, 45 min post-exercise; POST + 210, 210 min post-exercise. * Different from REST in females, † Different from POST + 30 in females, # Different from 210 min POST in females, < 0.05.<p><b>Copyright information:</b></p><p>Taken from "Gender impacts the post-exercise substrate and endocrine response in trained runners"</p><p>http://www.jissn.com/content/5/1/7</p><p>Journal of the International Society of Sports Nutrition 2008;5():7-7.</p><p>Published online 26 Feb 2008</p><p>PMCID:PMC2288589.</p><p></p

Gender impacts the post-exercise substrate and endocrine response in trained runners-2

± SEM. REST, prior to exercise; POST + 30, 30 min post-exercise. * Different from REST in males, < 0.05.<p><b>Copyright information:</b></p><p>Taken from "Gender impacts the post-exercise substrate and endocrine response in trained runners"</p><p>http://www.jissn.com/content/5/1/7</p><p>Journal of the International Society of Sports Nutrition 2008;5():7-7.</p><p>Published online 26 Feb 2008</p><p>PMCID:PMC2288589.</p><p></p

Gender impacts the post-exercise substrate and endocrine response in trained runners-3

D as mean ± SEM. REST, prior to exercise; POST + 30, 30 min post-exercise; POST + 45, 45 min post-exercise. * Different from REST in males, < 0.05, † Different from POST + 30 in males, < 0.001.<p><b>Copyright information:</b></p><p>Taken from "Gender impacts the post-exercise substrate and endocrine response in trained runners"</p><p>http://www.jissn.com/content/5/1/7</p><p>Journal of the International Society of Sports Nutrition 2008;5():7-7.</p><p>Published online 26 Feb 2008</p><p>PMCID:PMC2288589.</p><p></p