Appetite and energy intake responses to breakfast consumption and carbohydrate supplementation in hypoxia.
- 作者列表："Griffiths A","Deighton K","Shannon OM","Boos C","Rowe J","Matu J","King R","O'Hara JP
PURPOSE:The purpose of experiment one was to determine the appetite, acylated ghrelin and energy intake response to breakfast consumption and omission in hypoxia and normoxia. Experiment two aimed to determine the appetite, acylated ghrelin and energy intake response to carbohydrate supplementation after both breakfast consumption and omission in hypoxia. METHODS:In experiment one, twelve participants rested and exercised once after breakfast consumption and once after omission in normobaric hypoxia (4300 m: FiO2 ~11.7%) and normoxia. In experiment two, eleven participants rested and exercised in normobaric hypoxia (4300 m: FiO2 ~11.7%), twice after consuming a high carbohydrate breakfast and twice after breakfast omission. Participants consumed both a carbohydrate (1.2g·min-1 glucose) and a placebo beverage after breakfast consumption and omission. Measures of appetite perceptions and acylated ghrelin were taken at regular intervals throughout both experiments and an ad-libitum meal was provided post-exercise to quantify energy intake. RESULTS:Breakfast consumption had no significant effect on post exercise energy intake or acylated ghrelin concentrations, despite reductions in appetite perceptions. As such, breakfast consumption increased total trial energy intake compared with breakfast omission in hypoxia (7136 ± 2047 kJ vs. 5412 ± 1652 kJ; p = 0.02) and normoxia (9276 ± 3058 vs. 6654 ± 2091 kJ; p < 0.01). Carbohydrate supplementation had no effect on appetite perceptions or acylated ghrelin concentrations after breakfast consumption or omission. As such, carbohydrate supplementation increased total energy intake after breakfast consumption (10222 ± 2831 kJ vs. 7695 ± 1970 kJ p < 0.01) and omission (8058 ± 2574 kJ vs. 6174 ± 2222 kJ p = 0.02). CONCLUSION:Both breakfast consumption and carbohydrate supplementation provide beneficial dietary interventions for increasing energy intake in hypoxic conditions.
目的: 实验一的目的是确定在缺氧和常氧条件下，食欲、酰化 ghrelin 和能量摄入对早餐消耗和遗漏的反应。实验二旨在确定缺氧时无论吃早餐还是不吃早餐后，食欲、酰化 ghrelin 和能量摄入对碳水化合物补充的反应。 方法: 实验一，12 名受试者在常压缺氧 (4300 m: FiO2 ~ 11.7%) 和常氧状态下，早餐后休息和锻炼 1 次，省略后休息和锻炼 1 次。在实验二中，11 名参与者在常压缺氧 (4300 m: FiO2 ~ 11.7%) 中休息和锻炼，两次在食用高碳水化合物早餐后，两次在早餐遗漏后。参与者在早餐和省略后同时摄入碳水化合物 (1.2g · min-1 葡萄糖) 和安慰剂饮料。在两项实验中，每隔一段时间采取食欲感知和酰化 ghrelin 的测量，并在运动后提供随意餐以量化能量摄入。 结果: 早餐消费量对运动后能量摄入或酰化 ghrelin 浓度无显著影响，尽管食欲感知减少。因此，在缺氧时，与早餐遗漏相比，早餐消耗增加了总试验能量摄入 (7136 ± 2047 kJ vs. 5412 ± 1652 kJ; p = 0.02) 和常氧 (9276 ± 3058 vs. 6654 ± 2091 kJ; p <0.01)。补充碳水化合物对早餐摄入或遗漏后的食欲感知或酰化 ghrelin 浓度无影响。因此，补充碳水化合物增加了早餐消费后的总能量摄入 (10222 ± 2831 kJ vs. 7695 ± 1970 kJ p < 0.01) 和遗漏 (8058 ± 2574 kJ vs. 6174 ± 2222 kJ p = 0.02)。 结论: 在低氧条件下，早餐摄入和碳水化合物补充都为增加能量摄入提供了有益的膳食干预。
METHODS:BACKGROUND:Given the importance of habitual dietary protein intake, distribution patterns and dietary sources in the aetiology of age-related declines of muscle mass and function, the present study examined these factors as a function of sex and age in Irish adults aged 18-90 years comprising The National Adult Nutrition Survey (NANS). METHODS:In total, 1051 (males, n = 523; females, n = 528) undertook a 4-day semi-weighed food diary. Total, body mass relative intake and percentage contribution to total energy intake of dietary protein were determined in addition to protein distribution scores (PDS), as well as the contribution of food groups, animal- and plant-based foods to total protein intake. RESULTS:Total and relative protein intake [mean (SD)] were highest in those aged 18-35 years [96 (3) g day , 1.32 (0.40) g kg day ], with lower protein intakes with increasing age (i.e. in adults aged ≥65 years [82 (22) g, 1.15 (0.34) g kg day , P < 0.001 for both]. Differences in protein intake between age groups were more pronounced in males compared to females. Protein distribution followed a skewed pattern for all age groups [breakfast, 15 (10) g; lunch, 30 (15) g; dinner, 44 (17) g]. Animal-based foods were the dominant protein source within the diet [63% (11%) versus 37% (11%) plant protein, P < 0.001]. CONCLUSIONS:Protein intake and the number of meals reaching the purported threshold for maximising post-prandial anabolism were highest in young adults, and lower with increasing age. For main meals, breakfast provided the lowest quantity of protein across all age categories and may represent an opportunity for improving protein distribution, whereas, in older adults, increasing the number of meals reaching the anabolic threshold regardless of distribution pattern may be more appropriate.
METHODS:BACKGROUND:Low cardiorespiratory fitness (CRF) increases risk of all-cause mortality and cardiovascular events. Periodic CRF assessment can have an important preventive function. OBJECTIVE:To develop a protocol-free method to estimate CRF in daily life based on heart rate (HR) and body acceleration measurements. METHODS:Acceleration and HR data were collected from 37 subjects (M=49%) while performing a standardized laboratory activity protocol (sitting, walking, running, cycling) and during a 5-days free-living monitoring period. CRF was determined by oxygen uptake (VO2max) during maximal exercise testing. A doubly-labeled water validated equation was used to predict total energy expenditure (TEE) from acceleration data. A fitness index was defined as the ratio between TEE and HR (TEE-pulse). Activity recognition techniques were used to process acceleration features and classify sedentary, ambulatory and other activity types. Regression equations based on TEE-pulse data from each activity type were developed to predict VO2max. RESULTS:TEE-pulse measured within each activity type of the laboratory protocol was highly correlated to VO2max (r from 0.74 to 0.91). Averaging the outcome of each activity-type specific equation based on TEE-pulse from the laboratory data led to accurate estimates of VO2max (RMSE: 300.0 mlO2/min or 10%). The difference between laboratory and free-living determined TEE-pulse was 3.7 ± 11% (r =0.85). The prediction method preserved the prediction accuracy when applied to free-living data (RMSE: 367 mlO2/min or 12%). CONCLUSIONS:Measurements of body acceleration and HR can be used to predict VO2max in daily life. Activity-specific prediction equations are needed to achieve highly accurate estimates of CRF.
METHODS:OBJECTIVE:Postprandial dyslipidemia is a common feature of insulin resistant states and contributes to increased cardiovascular disease risk. Recently, bile acids have been recognized beyond their emulsification properties as important signaling molecules that promote energy expenditure, improve insulin sensitivity, and lower fasting lipemia. While bile acid receptors have become novel pharmaceutical targets, their effects on postprandial lipid metabolism remain unclear. Here we investigated the potential role of bile acids in regulation of postprandial chylomicron production and triglyceride excursion. Approach and Results: Healthy C57BL/6 mice were given an intraduodenal infusion of taurocholic acid (TA) under fat-loaded conditions and circulating lipids were measured. Targeting of bile acid receptors was achieved with GW4064, a synthetic agonist to the farnesoid X receptor (FXR), and with deoxycholic acid (DCA), an activator of the Takeda G-protein-coupled receptor 5. TA, GW4064, and DCA treatments all lowered postprandial lipemia. FXR agonism also reduced intestinal triglyceride content and activity of microsomal triglyceride transfer protein, involved in chylomicron assembly. Importantly, TA effects (but not DCA) were largely lost in FXR knockout mice. These bile acid effects are reminiscent of the anti-diabetic hormone glucagon-like peptide-1 (GLP-1). While the GLP-1 receptor agonist exendin-4 retained its ability to acutely lower postprandial lipemia during bile acid sequestration and FXR deficiency, it did raise hepatic expression of the rate limiting enzyme for bile acid synthesis. CONCLUSIONS:Bile acid signaling may be an important mechanism of controlling dietary lipid absorption and bile acid receptors may constitute novel targets for the treatment of postprandial dyslipidemia.