Effects of co-ingesting glucose and whey protein on blood glucose, plasma insulin and glucagon concentrations, and gastric emptying, in older men with and without type 2 diabetes.

AIM: To investigate whether co-ingestion of dietary protein with, or before, carbohydrate may be a useful strategy to reduce postprandial hyperglycaemia in older men with type 2 diabetes (T2D). MATERIALS AND METHODS: Blood glucose, plasma insulin and glucagon concentrations were measured for 180 minutes following ingestion of a drink containing 30 g of glucose (G; 120 kcal), 30 g of whey protein (120 kcal), 30 g of glucose plus 30 g of whey protein (GP; 240 kcal), or control (~2 kcal) in older men with T2D (n = 10, 77 ± 1 years; 31 ± 1.7 kg/m2 ) and without T2D (n = 10, 78 ± 2 years; 27 ± 1.4 kg/m2 ). Mixed model analysis was used. RESULTS: GP versus G markedly reduced the increase in blood glucose concentrations (P < .001) and had a synergistic effect on the increase in insulin concentrations (P < .001), in men both with and without T2D. Glucose concentrations were higher in men with T2D compared with those without T2D, whereas insulin and glucagon concentrations were largely unaffected by the presence of T2D. Gastric emptying was faster in men with T2D than in those without T2D. CONCLUSIONS: The ability of whey protein to reduce carbohydrate-induced, postprandial hyperglycaemia is retained in older men with T2D compared with those without T2D, and whey protein supplementation may be a useful strategy in the prevention and management of T2D in older people.

Muscle Protein Synthesis after Protein Administration in Critical Illness.

Rationale: Dietary protein may attenuate the muscle atrophy experienced by patients in the ICU, yet protein handling is poorly understood. Objectives: To quantify protein digestion and amino acid absorption and fasting and postprandial myofibrillar protein synthesis during critical illness. Methods: Fifteen mechanically ventilated adults (12 male; aged 50 ± 17 yr; body mass index, 27 ± 5 kg⋅m-2) and 10 healthy control subjects (6 male; 54 ± 23 yr; body mass index, 27 ± 4 kg⋅m-2) received a primed intravenous L-[ring-2H5]-phenylalanine, L-[3,5-2H2]-tyrosine, and L-[1-13C]-leucine infusion over 9.5 hours and a duodenal bolus of intrinsically labeled (L-[1-13C]-phenylalanine and L-[1-13C]-leucine) intact milk protein (20 g protein) over 60 minutes. Arterial blood and muscle samples were taken at baseline (fasting) and for 6 hours following duodenal protein administration. Data are mean ± SD, analyzed with two-way repeated measures ANOVA and independent samples t test. Measurements and Main Results: Fasting myofibrillar protein synthesis rates did not differ between ICU patients and healthy control subjects (0.023 ± 0.013% h-1 vs. 0.034 ± 0.016% h-1; P = 0.077). After protein administration, plasma amino acid availability did not differ between groups (ICU patients, 54.2 ± 9.1%, vs. healthy control subjects, 61.8 ± 13.1%; P = 0.12), and myofibrillar protein synthesis rates increased in both groups (0.028 ± 0.010% h-1 vs. 0.043 ± 0.018% h-1; main time effect P = 0.046; P-interaction = 0.584) with lower rates in ICU patients than in healthy control subjects (main group effect P = 0.001). Incorporation of protein-derived phenylalanine into myofibrillar protein was ∼60% lower in ICU patients (0.007 ± 0.007 mol percent excess vs. 0.017 ± 0.009 mol percent excess; P = 0.007). Conclusions: The capacity for critically ill patients to use ingested protein for muscle protein synthesis is markedly blunted despite relatively normal protein digestion and amino acid absorption.

Acute effects of whey protein, alone and mixed with other macronutrients, on blood pressure and heart rate in older men.

BACKGROUND: Caloric supplements are increasingly used by older people, aiming to increase their daily protein intake. These high caloric drinks, rich in glucose and whey-protein in particular, may result in potential harmful decreases in blood pressure (BP). The effect of ingesting whey-protein with glucose and fat on BP is unknown. It has also been assumed that the maximum fall in systolic blood pressure occurs within 2 h of a meal. METHODS: This study aimed to determine in older men, the effects of whey-protein, alone and mixed with other macronutrients, on systolic (SBP) and diastolic (DBP) blood pressure and heart rate (HR) in older men for 3 h. Thirteen older men (age 75 ± 2yrs; body mass index (BMI) 25.6 ± 0.6 kg/m2) ingested a drink on separate study days: (i) 70 g whey-protein (P280); (ii) 14 g whey-protein, 28 g carbohydrate, 12.4 g fat (M280); (iii) 70 g whey-protein, 28 g carbohydrate, 12.4 g fat (M504); or (iv) a non-caloric control drink (C). RESULTS: SBP decreased after all three nutrient drinks compared to the C, with the greatest reduction after the M504 drink (P = 0.008). Maximal decreases in SBP (C: -14 ± 2 mmHg, P280: -22 ± 2 mmHg, M280: -22 ± 4 mmHg, M504: -24 ± 3 mmHg) occurred about 2 h after drink ingestion and this fall was sustained thereafter (120-180 min: P280 and M504 vs. C P < 0.05). Maximum DBP decreases and HR increases occurred after M504, with no differences between the effects of the P280 and M280 drinks. CONCLUSIONS: The effects of whey-protein containing drinks to lower BP and increase HR appear to be primarily dependent on their energy content rather than macronutrient composition and may persist for at least 3 h after ingestion,. Pure whey-protein drinks may represent the best approach to maximize protein intake without increasing the potential for deleterious BP falls in older people. TRIAL REGISTRATION: ACTRN12614000846628 , 14/03/2019.

Multidisciplinary lifestyle intervention in children and adolescents - results of the project GRIT (Growth, Resilience, Insights, Thrive) pilot study.

BACKGROUND: During childhood and adolescence leading behavioural risk factors for the development of cardiometabolic diseases include poor diet quality and sedentary lifestyle. The aim of this study was to determine the feasibility and effect of a real-world group-based multidisciplinary intervention on cardiorespiratory fitness, diet quality and self-concept in sedentary children and adolescents aged 9 to 15 years. METHODS: Project GRIT (Growth, Resilience, Insights, Thrive) was a pilot single-arm intervention study. The 12-week intervention involved up to three outdoor High Intensity Interval Training (HIIT) running sessions per week, five healthy eating education or cooking demonstration sessions, and one mindful eating and Emotional Freedom Technique psychology session. Outcome measures at baseline and 12-week follow-up included maximal graded cardiorespiratory testing, the Australian Child and Adolescent Eating Survey, and Piers-Harris 2 children's self-concept scale. Paired samples t-test or Wilcoxon signed-rank test were used to compare baseline and follow-up outcome measures in study completers only. RESULTS: Of the 38 recruited participants (median age 11.4 years, 53% male), 24 (63%) completed the 12-week intervention. Dropouts had significantly higher diet quality at baseline than completers. Completers attended a median 58 (IQR 55-75) % of the 33 exercise sessions, 60 (IQR 40-95) % of the dietary sessions, and 42% attended the psychology session. No serious adverse events were reported. Absolute VO2peak at 12 weeks changed by 96.2 ± 239.4 mL/min (p = 0.06). As a percentage contribution to energy intake, participants increased their intake of healthy core foods by 6.0 ± 11.1% (p = 0.02) and reduced median intake of confectionary (- 2.0 [IQR 0.0-3.0] %, p = 0.003) and baked products (- 1.0 [IQR 0.0-5.0] %, p = 0.02). Participants significantly improved self-concept with an increase in average T-Score for the total scale by 2.8 ± 5.3 (p = 0.02) and the 'physical appearance and attributes' domain scale by median 4.0 [IQR 0.5-4.0] (p = 0.02). CONCLUSIONS: The 12-week group-based multidisciplinary lifestyle intervention for children and adolescents improved diet quality and self-concept in study completers. Future practice and research should focus on providing sustainable multidisciplinary lifestyle interventions for children and adolescents aiming to improve long-term health and wellbeing. TRIAL REGISTRATION: ANZCTR, ACTRN12618001249246. Registered 24 July 2019 - Retrospectively registered.

The ageing gastrointestinal tract.

PURPOSE OF REVIEW: This article reviews the impact of ageing on the gastrointestinal tract, including effects on the absorption of nutrients and drugs and the gastrointestinal tract defence system against ingested pathogens. RECENT FINDINGS: Recent publications support earlier observations of an age-related selective decline in gut function including changes in taste, oesophageal sphincter motility, gastric emptying, and neurons of the myenteric plexus related to gut transit which may impact the nutritional status. Ageing is also associated with structural and functional mucosal defence defects, diminished abilities to generate protective immunity, and increased incidence of inflammation and oxidative stress. A number of gastrointestinal disorders occur more frequently in the elderly population. SUMMARY: Alterations in gut function with ageing have particular implications for oesophageal, gastric, and colonic motility. Older individuals are particularly susceptible to malnutrition, postprandial hypotension, dysphagia, constipation, and faecal incontinence. Decrease in the number of nerve cells of the myenteric plexus that impact digestive absorption and the surface area of the small intestine because of degeneration of villi may lead to blunted absorption of nutrients. Impairment of the intestinal immune system as a result of ageing, including the mucosal layer of the gastrointestinal tract, appears to be a significant contributor to the age-related increase in the incidence and severity of infections.

Lesser suppression of energy intake by orally ingested whey protein in healthy older men compared with young controls.

Protein-rich supplements are used widely for the management of malnutrition in young and older people. Protein is the most satiating of the macronutrients in young. It is not known how the effects of oral protein ingestion on energy intake, appetite, and gastric emptying are modified by age. The aim of the study was to determine the suppression of energy intake by protein compared with control and underlying gastric-emptying and appetite responses of oral whey protein drinks in eight healthy older men (69-80 yr) compared with eight young male controls (18-34 yr). Subjects were studied on three occasions to determine the effects of protein loads of 30 g/120 kcal and 70 g/280 kcal compared with a flavored water control-drink (0 g whey protein) on energy intake (ad libitum buffet-style meal), and gastric emptying (three-dimensional-ultrasonography) and appetite (0-180 min) in a randomized, double-blind, cross-over design. Energy intake was suppressed by the protein compared with control (P = 0.034). Suppression of energy intake by protein was less in older men (1 ± 5%) than in young controls (15 ± 2%; P = 0.008). Cumulative energy intake (meal+drink) on the protein drink days compared with the control day increased more in older (18 ± 6%) men than young (1 ± 3%) controls (P = 0.008). Gastric emptying of all three drinks was slower in older men (50% gastric-emptying time: 68 ± 5 min) than young controls (36 ± 5 min; P = 0.007). Appetite decreased in young, while it increased in older (P < 0.05). In summary, despite having slower gastric emptying, elderly men exhibited blunted protein-induced suppression of energy intake by whey protein compared with young controls, so that in the elderly men, protein ingestion increased overall energy intake more than in the young men.

Sleep health primary care clinical resource.

BACKGROUND: Obstructive sleep apnoea (OSA) and insomnia are the two most common sleep disorders and are frequent reasons for presentation in Australian general practice. OBJECTIVE: This article describes the development, content and suggested uses of the online sleep health primary care clinical resource, which provides general practitioners and other primary healthcare professionals with evidence-based information on the aetiology, assessment, management, referral and ongoing care for OSA and chronic insomnia. DISCUSSION: The Royal Australian College of General Practitioners-accepted clinical resource for the management of OSA and chronic insomnia in primary care was developed by the Australian National Centre for Sleep Health Services Research. The resource is designed to be used during consultations (eg following the steps in assessment and management and the use of online questionnaires for the assessment of OSA [Epworth Sleepiness Scale/OSA50/STOP-Bang] and insomnia [Sleep Condition Indicator/and Insomnia Severity Index]) and as an education/training tool (eg evidence on the role of continuous positive airway pressure/mandibular advancement splints for management of OSA and brief behavioural therapy for insomnia/cognitive behavioural therapy for insomnia for the management of insomnia).

Normal protein intake is required for body weight loss and weight maintenance, and elevated protein intake for additional preservation of resting energy expenditure and fat free mass.

Energy-restricted high-protein diets (HPDs) have shown favorable results for body weight (BW) management, yet studies differ in their outcomes depending on the dietary protein content. Our objective was to determine the effects of dietary protein content on BW loss-related variables during a 6-mo energy restriction with the use of diets containing protein at the level of requirement [normal-protein diet (NPD), 0.8 g · kg BW(-1) (.) d(-1)] and above (HPD, 1.2 g · kg BW(-1) (.) d(-1)). In overweight and obese participants (24 men and 48 women), BW, body composition, and metabolic responses were assessed before and after subsequent energy intakes of 100, 33, and 67% of the original individual daily energy requirements. Protein intake was consistent in the NPD (0.8 ± 0.3 g · kg BW(-1) (.) d(-1)) and HPD (1.2 ± 0.3 g · kg BW(-1) (.) d(-1)) groups throughout the study (P < 0.001). BMI and body fat mass similarly decreased in the NPD and HPD groups (P < 0.01). Fat free mass (FFM), resting energy expenditure (REE) compared with predicted REE, and diastolic blood pressure (DBP) changed favorably with the HPD compared with the NPD group after BW loss (P < 0.05). A NPD of 0.8 g · kg BW(-1) (.) d(-1) is sufficient for BW management, whereas a HPD of 1.2 g · kg BW(-1) (.) d(-1) is necessary for preservation of REE and a stronger initial sparing effect of FFM and lowering of DBP.

The prevention and reduction of weight loss in an acute tertiary care setting: protocol for a pragmatic stepped wedge randomised cluster trial (the PRoWL project).

BACKGROUND: Malnutrition, with accompanying weight loss, is an unnecessary risk in hospitalised persons and often remains poorly recognised and managed. The study aims to evaluate a hospital-wide multifaceted intervention co-facilitated by clinical nurses and dietitians addressing the nutritional care of patients, particularly those at risk of malnutrition. Using the best available evidence on reducing and preventing unplanned weight loss, the intervention (introducing universal nutritional screening; the provision of oral nutritional supplements; and providing red trays and additional support for patients in need of feeding) will be introduced by local ward teams in a phased way in a large tertiary acute care hospital. METHODS/DESIGN: A pragmatic stepped wedge randomised cluster trial with repeated cross section design will be conducted. The unit of randomisation is the ward, with allocation by a random numbers table. Four groups of wards (n = 6 for three groups, n = 7 for one group) will be randomly allocated to each intervention time point over the trial. Two trained local facilitators (a nurse and dietitian for each group) will introduce the intervention. The primary outcome measure is change in patient's body weight, secondary patient outcomes are: length of stay, all-cause mortality, discharge destinations, readmission rates and ED presentations. Patient outcomes will be measured on one ward per group, with 20 patients measured per ward per time period by an unblinded researcher. Including baseline, measurements will be conducted at five time periods. Staff perspectives on the context of care will be measured with the Alberta Context Tool. DISCUSSION: Unplanned and unwanted weight loss in hospital is common. Despite the evidence and growing concern about hospital nutrition there are very few evaluations of system-wide nutritional implementation programs. This project will test the implementation of a nutritional intervention across one hospital system using a staged approach, which will allow sequential rolling out of facilitation and project support. This project is one of the first evidence implementation projects to use the stepped wedge design in acute care and we will therefore be testing the appropriateness of the stepped wedge design to evaluate such interventions. TRIAL REGISTRATION: ACTRN12611000020987.

Blood Pressure and Heart Rate Responses following Dietary Protein Intake in Older Men.

Postprandial hypotension (PPH) occurs frequently in older people >65 years old. Protein-rich supplements, particularly whey protein (WP), are increasingly used by older people for various health benefits. We have reported that 70 g WP drinks cause significant, and in some cases marked, falls in blood pressure (BP) in older men. The effects of lower, more widely used, doses (~30 g) on systolic (SBP) and diastolic (DBP) blood pressure and heart rate (HR) are not known. In a randomized order, eight older men (age: 72 ± 1 years; body mass index (BMI): 25 ± 1 kg/m2) after overnight fast ingested a drink containing (i) a non-caloric control (~2 kcal), (ii) 30 g of whey protein (120 kcal; 'WP30'), or (iii) 70 g of whey protein (280 kcal; 'WP70'). The BP and HR were measured in this pilot study with an automated device before and at 3-min intervals for 180 min following drink ingestion. Drink condition effects were determined by repeated-measures ANOVA. The SBP decreased after both WP drinks compared to the control (p = 0.016), particularly between 120 and 180 min, with no difference in the effects of WP30 and WP70. The SBP decreased by ≥20 mmHg in more than 50% of people after both WP drinks (WP30: 63%; WP70: 75%) compared to 38% after the control. The maximum fall in the SBP occurred during the third hour, with the nadir occurring latest after WP70. The DBP decreased non-significantly by several mmHg more after the WP drinks than after the control. The maximum HR increases occurred during the third hour, with the greatest increase after WP70. The SBP decreased after both WP drinks compared to the control, with the effects most evident between 120 and 180 min. Accordingly, ingestion of even relatively modest protein loads in older men has the potential to cause PPH.

Plasma GLP-1 Response to Oral and Intraduodenal Nutrients in Health and Type 2 Diabetes-Impact on Gastric Emptying.

CONTEXT: Both gastric emptying and the secretion of glucagon-like peptide-1 (GLP-1) are major determinants of postprandial glycemia in health and type 2 diabetes (T2D). GLP-1 secretion after a meal is dependent on the entry of nutrients into the small intestine, which, in turn, slows gastric emptying. OBJECTIVE: To define the relationship between gastric emptying and the GLP-1 response to both oral and small intestinal nutrients in subjects with and without T2D. METHODS: We evaluated: (i) the relationship between gastric emptying (breath test) and postprandial GLP-1 levels after a mashed potato meal in 73 individuals with T2D; (ii) inter-individual variations in GLP-1 response to (a) intraduodenal glucose (4 kcal/min) during euglycemia and hyperglycemia in 11 healthy and 12 T2D, subjects, (b) intraduodenal fat (2 kcal/min) in 15 T2D subjects, and (c) intraduodenal protein (3 kcal/min) in 10 healthy subjects; and (iii) the relationship between gastric emptying (breath test) of 75 g oral glucose and the GLP-1 response to intraduodenal glucose (4 kcal/min) in 21 subjects (9 healthy, 12 T2D). RESULTS: The GLP-1 response to the mashed potato meal was unrelated to the gastric half-emptying time (T50). The GLP-1 responses to intraduodenal glucose, fat, and protein varied substantially between individuals, but intra-individual variation to glucose was modest. The T50 of oral glucose was related directly to the GLP-1 response to intraduodenal glucose (r = 0.65, P = 0.002). CONCLUSION: In a given individual, gastric emptying is not a determinant of the postprandial GLP-1 response. However, the intrinsic gastric emptying rate is determined in part by the responsiveness of GLP-1 to intestinal nutrients.

Comparative Effects of Co-Ingesting Whey Protein and Glucose Alone and Combined on Blood Glucose, Plasma Insulin and Glucagon Concentrations in Younger and Older Men.

The ingestion of dietary protein with, or before, carbohydrate may be a useful strategy to reduce postprandial hyperglycemia, but its effect in older people, who have an increased predisposition for type 2 diabetes, has not been clarified. Blood glucose, plasma insulin and glucagon concentrations were measured for 180 min following a drink containing either glucose (120 kcal), whey-protein (120 kcal), whey-protein plus glucose (240 kcal) or control (~2 kcal) in healthy younger (n = 10, 29 ± 2 years; 26.1 ± 0.4 kg/m2) and older men (n = 10, 78 ± 2 years; 27.3 ± 1.4 kg/m2). Mixed model analysis was used. In both age groups the co-ingestion of protein with glucose (i) markedly reduced the increase in blood glucose concentrations following glucose ingestion alone (p < 0.001) and (ii) had a synergistic effect on the increase in insulin concentrations (p = 0.002). Peak insulin concentrations after protein were unaffected by ageing, whereas insulin levels after glucose were lower in older than younger men (p < 0.05) and peak insulin concentrations were higher after glucose than protein in younger (p < 0.001) but not older men. Glucagon concentrations were unaffected by age. We conclude that the ability of whey-protein to reduce carbohydrate-induced postprandial hyperglycemia is retained in older men and that protein supplementation may be a useful strategy in the prevention and management of type 2 diabetes in older people.

Effects of a supra-sustained gelatin-milk protein diet compared with (supra-)sustained milk protein diets on body-weight loss.

Diets higher in protein content result in increased satiety and energy expenditure. In the short term, gelatin showed stronger hunger suppression and less subsequent energy intake compared with other proteins. The present study investigated whether a supra-sustained gelatin-milk protein (GMP) diet promotes weight loss compared with a sustained milk protein (SMP) diet and a supra-sustained milk protein (SSMP) diet during an 8-week diet period. A total of seventy-two healthy subjects (31·2 (sd 4·8) kg/m2; 43 (sd 10) years) followed one of the three diets in a subject-specific amount: SMP, SSMP or GMP diet. During weeks 1-4, energy intake was 100 % of individual energy requirement: 10, 40 and 50 % of energy (En %) as protein, fat and carbohydrate, respectively (SMP diet), and 20, 30 and 50 En % as protein, fat and carbohydrate, respectively (SSMP diet or GMP diet). During weeks 5-8, energy intake was 33 % of individual energy requirement: 30, 35 and 35 En % as protein, fat and carbohydrate, respectively (SMP diet), and 60, 5 and 35 En % as protein, fat and carbohydrate, respectively (SSMP diet or GMP diet). Thus, absolute protein intake was kept constant throughout per subject. Significant decreases in BMI (P < 0·0001) were similar between the GMP ( - 1·7 (sd 0·5) kg/m2) and the SMP ( - 2·1 (sd 0·8) kg/m2) and SSMP ( - 1·6 (sd 0·5) kg/m2) diets. Decreases in fat-free mass (FFM), fat mass (FM) and FM %, and increases in FFM % were similar between the GMP and both control diets. Changes in RQ differed (P < 0·05) between the GMP ( - 0·01 (sd 0·06)) and SSMP ( - 0·04 (sd 0·04)) diets. Changes in HDL concentrations differed (P < 0·05) between the GMP ( - 0·21 (sd 0·18) mmol/l) and the SMP and SSMP diets ( - 0·08 (sd 0·18) mmol/l and - 0·09 (sd 0·26) mmol/l, respectively). In conclusion, a gelatin-milk protein diet does not induce more beneficial effects during an 8-week weight-loss period compared with a SMP or SSMP diet.

Rational Use of Protein Supplements in the Elderly-Relevance of Gastrointestinal Mechanisms.

Protein supplements are increasingly used by older people to maintain nutrition and prevent or treat loss of muscle function. Daily protein requirements in older people are in the range of 1.2 gm/kg/day or higher. Many older adults do not consume this much protein and are likely to benefit from higher consumption. Protein supplements are probably best taken twice daily, if possible soon after exercise, in doses that achieve protein intakes of 30 gm or more per episode. It is probably not important to give these supplements between meals, as we have shown no suppressive effects of 30 gm whey drinks, and little if any suppression of 70 gm given to older subjects at varying time intervals from meals. Many gastrointestinal mechanisms controlling food intake change with age, but their contributions to changes in responses to protein are not yet well understood. There may be benefits in giving the supplement with rather than between meals, to achieve protein intakes above the effective anabolic threshold with lower supplement doses, and have favourable effects on food-induced blood glucose increases in older people with, or at risk of developing, type 2 diabetes mellitus; combined protein and glucose drinks lower blood glucose compared with glucose alone in older people.

Effects of age on blood pressure and heart rate responses to whey protein in younger and older men.

BACKGROUND: Postprandial falls in blood pressure (BP) are more common in older compared to younger individuals. The effects of protein compared to carbohydrates and fat on postprandial BP, and the relation to gastric emptying rates, are poorly studied. OBJECTIVES: To determine the effects of a whey protein compared to a control drink on systolic BP (SBP) and diastolic BP (DBP), and heart rate (HR) in healthy younger and older men, and to relate these effects to gastric emptying. DESIGN: A pooled analyses of two randomized, double-blind, cross-over studies. SETTING: Two acute clinical intervention studies with identical study design. PARTICIPANTS: Nineteen older (age: 74 ± 1 years, body mass index: 26 ± 1 kg/m2 ) and 13 younger (23 ± 1 years, 24 ± 1 kg/m2 ) healthy men. INTERVENTION: A 70 g/280 kcal whey-protein or control (water with diet cordial, ~2 kcal) drink (450 ml). MEASUREMENTS: BP and HR were assessed with an automated device immediately before and at 3-min intervals after drink ingestion (0-180 min). Gastric emptying of the drinks was measured using 3D ultrasonography (0-180 min). RESULTS: Older versus younger men exhibited a greater fall in SBP (-23 ± 2 vs -15 ± 2 mmHg, p = 0.001) after whey-protein versus control, as BP did not change after the two drinks in younger men (p > 0.05). The nadir in SBP occurred later in the older than younger men (114 ± 11 vs 62 ± 14 min; p < 0.001), with SBP still apparently declining 180 min after whey-protein ingestion in the older men. The magnitude of the rise in HR was greater (p < 0.05) in the younger than older men. CONCLUSION: Following ingestion of 70 g whey protein, healthy older men exhibited a sustained fall in BP, despite an increase in HR, whereas in younger men there was no change in BP. BP may need to be monitored after high protein meals in older people at risk of postprandial hypotension.

Acute effects of whey protein on energy intake, appetite and gastric emptying in younger and older, obese men.

BACKGROUND: Obesity is becoming more prevalent in older people. A management strategy in obese, young adults is to increase dietary protein relative to other macronutrients. It is not clear if this is effective in obese, older individuals. Obesity may be associated with diminished sensitivity to nutrients. We have reported that a 30-g whey protein drink slows gastric emptying more, and suppresses energy intake less, in older, than younger, non-obese men. The aim of this study was to determine the effect of a 30 g whey protein drink on energy intake, GE and glycaemia in obese, older and younger men. METHODS: In randomized, double-blind order, 10 younger (age: 27 ± 2 years; BMI: 36 ± 2 kg/m²), and 10 older (72 ± 1 years; 33 ± 1 kg/m²), obese men were studied twice. After an overnight fast, subjects ingested a test drink containing 30 g whey protein (120 kcal) or control (2 kcal). Postprandial gastric emptying (antral area, 2D Ultrasound) and blood glucose concentrations were measured for 180 min. At t = 180 min subjects were given a buffet meal and ad libitum energy intake was assessed. RESULTS: Older subjects ate non-significantly less (~20%) that the younger subjects (effect of age, P = 0.16). Whey protein had no effect on subsequent energy intake (kcal) compared to control in either the younger (decrease 3 ± 8%) or older (decrease 2 ± 8%) obese men (age effect P > 0.05, protein effect P = 0.46, age × protein interaction effect P = 0.84). Whey protein slowed gastric emptying, to a similar degree in both age groups (50% emptying time: control vs. protein young men: 255 ± 5 min vs. 40 ± 7 min; older men: 16 ± 5 min vs. 50 ± 8 min; protein effect P = 0.001, age effect P = 0.93, age × protein interaction effect P = 0.13). CONCLUSIONS: Our data suggest that obesity may blunt/abolish the age-related effect of whey protein on suppression of energy intake.

Whey Protein Drink Ingestion before Breakfast Suppressed Energy Intake at Breakfast and Lunch, but Not during Dinner, and Was Less Suppressed in Healthy Older than Younger Men.

Ageing is associated with changes in feeding behavior. We have reported that there is suppression of energy intake three hours after whey protein drink ingestion in young, but not older, men. This study aimed to determine these effects over a time period of 9 h. Fifteen younger (27 ± 1 years, 25.8 ± 0.7 kg/m2) and 15 older (75 ± 2 years, 26.6 ± 0.8 kg/m2) healthy men were studied on three occasions on which they received, in a randomized order, a 30 g/120 kcal, 70 g/280 kcal whey-protein, or control (~2 kcal) drink. Ad-libitum energy intake (sum of breakfast, lunch, and dinner) was suppressed in a protein load responsive fashion (P = 0.001). Suppression was minimal at breakfast, substantial at lunch (~-16%, P = 0.001), no longer present by dinner, and was less in older than younger men (-3 ± 4% vs. -8 ± 4%, P = 0.027). Cumulative protein intake was increased in the younger and older men (+20% and +42%, P < 0.001). Visual analogue scale ratings of fullness were higher and desire to eat and prospective food consumption were lower after protein vs. control, and these effects were smaller in older vs. younger men (interaction effect P < 0.05). These findings support the use of whey-protein drink supplements in older people who aim to increase their protein intake without decreasing their overall energy intake.

Effects of Age on Acute Appetite-Related Responses to Whey-Protein Drinks, Including Energy Intake, Gastric Emptying, Blood Glucose, and Plasma Gut Hormone Concentrations-A Randomized Controlled Trial.

Protein-rich supplements are used commonly to increase energy intake in undernourished older people. This study aimed to establish age effects on energy intake, appetite, gastric emptying, blood glucose, and gut hormones in response to protein-rich drinks. In a randomized double-blind, order, 13 older men (age: 75 ± 2 yrs, body mass index (BMI): 26 ± 1 kg/m2) and 13 younger (23 ± 1 yrs, 24 ± 1 kg/m2) men consumed (i) a control drink (~2 kcal) or drinks (450 mL) containing protein/fat/carbohydrate: (ii) 70 g/0 g/0 g (280 kcal/'P280'), (iii) 14 g/12.4 g/28 g (280 kcal/'M280'), (iv) 70 g/12.4 g/28 g (504 kcal/'M504'), on four separate days. Appetite (visual analog scales), gastric emptying (3D ultrasonography), blood glucose, plasma insulin, ghrelin, cholecystokinin (CCK), glucagon-like peptide-1 (GLP-1) concentrations (0-180 min), and ad-libitum energy intake (180-210 min) were determined. Older men, compared to younger men, had higher fasting glucose and CCK concentrations and lower fasting GLP-1 concentrations (all p < 0.05). Energy intake by P280 compared to control was less suppressed in older men (increase: 49 ± 42 kcal) than it was in younger men (suppression: 100 ± 54 kcal, p = 0.038). After the caloric drinks, the suppression of hunger and the desire to eat, and the stimulation of fullness was less (p < 0.05), and the stimulation of plasma GLP-1 was higher (p < 0.05) in older men compared to younger men. Gastric emptying, glucose, insulin, ghrelin, and CCK responses were similar between age groups. In conclusion, ageing reduces the responses of caloric drinks on hunger, the desire to eat, fullness, and energy intake, and protein-rich nutrition supplements may be an effective strategy to increase energy intake in undernourished older people.

Relationship between perilipin gene polymorphisms and body weight and body composition during weight loss and weight maintenance.

BACKGROUND: Genetic variation in the perilipin (PLIN) gene may play a role in the etiology and treatment of obesity. OBJECTIVE: To examine different polymorphisms in the PLIN gene in relation to body-weight regulation. METHODS: 118 subjects followed a 6 wk VLCD, followed by 1 year weight maintenance. Body-weight (BW), body composition, leptin concentration, and polymorphisms of the PLIN gene: PLIN1:rs2289487, PLIN4:rs894160, PLIN6:rs1052700, PLIN5:rs2304795 and PLIN7:rs 2304796 were determined. RESULTS: BW loss during VLCD was 7.0+/-3.1 kg (p<0.05), and BW regain was 3.7+/-1.4 kg (p<0.05), including changes in body mass index (BMI), waist-circumference, body-composition and leptin concentrations (p<0.05). Linkage disequilibria were observed between PLIN1 and PLIN4: D' >0.9, r2=0.72; PLIN5 and PLIN7: D' >0.9, r2=0.85. In men, body weight, BMI, waist circumference, body fat, leptin concentrations were significantly lower for the haplotype of PLIN1 (C-alleles) and PLIN4 (A-alleles). In women weight loss and loss of fat mass were larger for the haplotype of PLIN1 (C-alleles) and PLIN4 (A-alleles). For PLIN6 genotypes body weight and body fat were lower for homozygotes of the minor allele (T/T) in the men; in the women leptin concentrations were lower. The haplotype of PLIN5 and PLIN7 consisting of A/G and G/G of PLIN5 and A/A of PLIN7 showed a reduction in FM: 5.9+/-0.6 kg vs 3.1+/-0.4 kg, % body fat: 5.5+/-0.6% vs 2.2+/-0.2%, and leptin: 20.5+/-10.8 ng/ml vs 12.9+/-6.7 ng/ml over time in the women (p<0.05). CONCLUSION: Since the haplotype of the minor alleles PLIN1-4, PLIN5-7 and PLIN6, was related to body-weight regulation at a lower level of body-weight in the men as well in the women we conclude that the PLIN1-4, 6, and 5-7 locus appears as a genetic influencer of obesity risk in humans.

Energy expenditure, satiety, and plasma ghrelin, glucagon-like peptide 1, and peptide tyrosine-tyrosine concentrations following a single high-protein lunch.

High-protein (HP) foods are more satiating and have a higher thermogenic effect than normal protein foods over the short-term as well as the long-term. We hypothesized that acute effects of higher protein intake on satiety may be related to acute metabolic and hormonal responses. The study was a single-blind, randomized, crossover design. Subjects underwent 2 indirect calorimetry tests for measurement of energy expenditure (EE) and substrate oxidation. After a standard subject-specific breakfast, subjects received 1 of 2 randomly assigned treatments: an appropriate protein (AP) lunch (10% energy (E) protein, 60%E carbohydrate, 30%E fat), or a HP lunch (25%E protein, 45%E carbohydrate, 30%E fat). The increase in postlunch EE tended to be greater after the HP lunch (0.85 +/- 0.32 kJ/min) than after the AP lunch (0.73 +/- 0.22 kJ/min) (P = 0.07). The respiratory quotient did not differ between the HP (0.84 +/- 0.04) and the AP (0.86 +/- 0.04) treatments. Satiety visual analogue scales (VAS) scores were significantly higher 30 and 120 min after the HP lunch than after the AP lunch. The area under the curve of the VAS score for satiety was higher after the HP lunch (263 +/- 61 mm/h) than after the AP lunch (AP 236 +/- 76 mm/h) (P < 0.02). Effects of the meals on satiety and diet-induced thermogenesis did not occur simultaneously with changes in plasma ghrelin, glucagon-like peptide 1, and peptide tyrosine-tyrosine concentrations. A single HP lunch, therefore, does not exert its acute effect on satiety through increased concentrations of satiety-related hormones. Other factors, which may explain the HP effect on satiety, may be metabolites or amino acids.