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.

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.

Muscle Protein Synthesis Following Protein Administration in Critical Illness

Rationale Dietary protein may attenuate the muscle atrophy experienced by patients in the Intensive Care Unit (ICU), yet protein handling is poorly understood. Objective To quantify protein digestion and amino acid absorption, and fasting and postprandial myofibrillar protein synthesis during critical illness. Methods Fifteen mechanically ventilated adults (12M; age 50±17y, Body Mass Index (BMI) 27±5kg·m-2) and 10 healthy controls (6M; 54±23y, BMI 27±4kg·m-2) received a primed intravenous L-[ring-2H5]-phenylalanine, L-[3,5-2H2]-tyrosine, and L-[1-13C]-leucine infusion over 9.5h, and a duodenal bolus of intrinsically-labelled (L-[1-13C]-phenylalanine and L-[1-13C]-leucine) intact milk protein (20g protein) over 60min. Arterial blood and muscle samples were taken at baseline (fasting) and for 6h following duodenal protein administration. Data are mean±SD; analysed with 2-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 controls (0.023±0.013 vs 0.034±0.016%/h; P=0.077). Following protein administration, plasma amino acid availability did not differ between groups (ICU patients 54.2±9.1 vs healthy controls 61.8±13.1%; P=0.12), and myofibrillar protein synthesis rates increased in both groups (0.028±0.010 vs 0.043±0.018 %/h, main time effect P=0.046, P-interaction=0.584) with lower rates in ICU patients compared to healthy controls (main group effect P=0.001). Incorporation of protein-derived phenylalanine into myofibrillar protein was ~60% lower in ICU patients (0.007±0.007 vs 0.017±0.009 mole % excess (MPE); P=0.007). Conclusion 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.

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.

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.

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.

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.

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.

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.

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/'P_280'), (iii) 14 g/12.4 g/28 g (280 kcal/'M_280'), (iv) 70 g/12.4 g/28 g (504 kcal/'M_504'), 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.

Acute Effects of Substitution, and Addition, of Carbohydrates and Fat to Protein on Gastric Emptying, Blood Glucose, Gut Hormones, Appetite, and Energy Intake

Whey protein, when ingested on its own, load-dependently slows gastric emptying and stimulates gut hormone concentrations in healthy young men. The aim of this study was to determine the effects of substitution, and addition, of carbohydrate (dextrose) and fat (olive oil) to whey protein. In randomized, double-blind order, 13 healthy young men (age: 23 ± 1 years, body mass index: 24 ± 1 kg/m²) ingested a control drink (450 mL; ~2 kcal/'control') or iso-volumetric drinks containing protein/carbohydrate/fat: (i) 14 g/28 g/12.4 g (280 kcal/'M_280'), (ii) 70 g/28 g/12.4 g (504kcal/'M_504'), and (iii) 70 g/0 g/0 g (280 kcal/'P_280'), on 4 separate study days. Gastric emptying (n = 11, 3D-ultrasonography), blood glucose, plasma insulin, ghrelin, cholecystokinin (CCK) and glucagon-like peptide-1 (GLP-1) concentrations (0⁻180 min), appetite (visual analogue scales), and ad-libitum buffet-meal energy intake (180⁻210 min) were determined. Substitution of protein with carbohydrate and fat was associated with faster gastric emptying (lower 50% emptying time (T50)), reduced suppression of ghrelin, and stimulation of GLP-1 (all P < 0.001); while the addition of carbohydrate and fat to protein did not affect gastric emptying or gut hormone responses significantly. Total energy intake (i.e., drink plus meal) was greater after all caloric drinks than control (P < 0.001). In conclusion, substitution of whey protein with dextrose and olive oil accelerated gastric emptying. Higher protein content of a mixed macronutrient drink increased gut hormone and insulin responses.

Effect of gender on the acute effects of whey protein ingestion on energy intake, appetite, gastric emptying and gut hormone responses in healthy young adults

BACKGROUND/OBJECTIVES

Protein supplements, usually drinks rich in whey protein, are used widely for weight loss purposes in overweight adults. Information comparing the effects of whey protein on appetite and energy intake in men and women is limited. The objective was to compare the acute effects of whey-protein intake on energy intake, appetite, gastric emptying and gut hormones in healthy young men and women.

SUBJECTS/METHODS

Gastric emptying (3D-ultrasonography), blood glucose and plasma insulin, glucagon, ghrelin, cholecystokinin (CCK), gastric inhibitory polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) concentrations (0-180 min), appetite (visual analogue scales), and ad libitum energy intake from a buffet meal (180-210 min) were determined after ingestion of 30 g (120 kcal) or 70 g (280 kcal) whey protein, or a flavoured-water control drink (~2 kcal) in 8 healthy young men (25 ± 2 y, 72 ± 3 kg, 23 ± 1 kg/m²) and 8 women (23 ± 1 y, 64 ± 2 kg, 24 ± 0.4 kg/m²).

RESULTS

There was a protein-load effect on gastric emptying, blood glucose, plasma insulin, glucagon, ghrelin, CCK, GIP and GLP-1 concentrations, and perceptions of hunger, desire to eat and prospective food consumption (P < 0.05). Ad libitum energy intake (average decrease of 206 ± 39 kcal (15 ± 2%) for men and of 46 ± 54 kcal (0 ± 26%) for women for the mean of the intakes after the 30 and 70 g whey-protein loads) and hunger were suppressed more by whey-protein ingestion in men than women (P = 0.046). There was no difference in suppression of energy intake between the 30 and 70 g protein loads (P = 0.75, interaction effect P = 0.19). Consequently, total energy intake (protein drink plus buffet meal) increased more compared to control in women than men (P = 0.010). The drinks emptied more slowly, and plasma glucagon, CCK and GLP-1 increased less after the protein drinks, in women than men (P < 0.05).

CONCLUSION

The acute effects of whey protein ingestion on appetite, energy intake, gastric emptying and gut hormone responses are influenced by gender in healthy young adults.

Effects of intraduodenal administration of the artificial sweetener sucralose on blood pressure and superior mesenteric artery blood flow in healthy older subjects

BACKGROUND

Postprandial hypotension (PPH) occurs frequently, particularly in older people and those with type 2 diabetes, and is associated with increased morbidity and mortality. The magnitude of the decrease in blood pressure (BP) induced by carbohydrate, fat, and protein appears to be comparable and results from the interaction of macronutrients with the small intestine, including an observed stimulation of mesenteric blood flow. It is not known whether artificial sweeteners, such as sucralose, which are widely used, affect BP.

OBJECTIVE

The aim of this study was to evaluate the effects of intraduodenal sucralose on BP and superior mesenteric artery (SMA) blood flow, compared with intraduodenal glucose and saline (control), in healthy older subjects.

DESIGN

Twelve healthy subjects (6 men, 6 women; aged 66-79 y) were studied on 3 separate occasions in a randomized, double-blind, crossover design. After an overnight fast, subjects had concurrent measurements of BP and heart rate (HR; automated device), SMA blood flow (Doppler ultrasound), and blood glucose (glucometer) during intraduodenal infusion of 1) glucose (25% wt:vol, ∼1400 mOsmol/L), 2) sucralose (4 mmol/L, ∼300 mOsmol/L), or 3) saline (0.9% wt:vol, ∼300 mOsmol/L) at a rate of 3 mL/min for 60 min followed by intraduodenal saline for a further 60 min.

RESULTS

There was a decrease in mean arterial BP (P < 0.001) during intraduodenal glucose [baseline (mean ± SEM): 91.7 ± 2.6 mm Hg compared with t = 60 min: 85.9 ± 2.8 mm Hg] but not during intraduodenal saline or intraduodenal sucralose. The HR (P < 0.0001) and SMA blood flow (P < 0.0001) also increased during intraduodenal glucose but not during intraduodenal saline or intraduodenal sucralose. As expected, blood glucose concentrations increased in response to glucose (P < 0.0001) but not saline or sucralose.

CONCLUSIONS

In healthy older subjects, intraduodenal administration of the artificial sweetener sucralose was not associated with changes in BP or SMA blood flow. Further studies are therefore warranted to determine the potential role for artificial sweeteners as a therapy for PPH. This trial was registered at http://www.ANZCTR.org.au as ACTRN12617001249347.

Serve Size and Estimated Energy and Protein Contents of Meals Prepared by 'Meals on Wheels' South Australia Inc.: Findings from a Meal Audit Study

An audit of ‘standard’ (STD) and ‘energy and protein fortified’ (HEHP) meals from Meals on Wheels (MOW) South Australia’s summer menu was conducted to evaluate the consistency, and serve size and nutrient contents, of their menu items. Twenty soups, 20 mains and 20 desserts from each of the STD and HEHP menus were prepared at the MOW South Australia’s kitchen and delivered to three ‘sham(dummy)-clients’ over a 5-week period. Each meal component was weighed in triplicate, to the nearest gram, the variation within the serve weight was calculated, and the overall energy and protein content of each meal was determined using FoodWorks (Xyris Software, Highgate Hill, Queensland, Australia). On average, the variability for soups and mains was ≤6% and for desserts was ≤10% and although the measured serve sizes of the MOW meals were consistently smaller than prescribed serve size, the differences were minor. As a percentage of recommended daily intakes (RDIs) for adults aged over 60 years, we calculated that the STD meals contained 21–39% for energy and 42–63% for protein while the HEHP meals contained 29–55% for energy and 46–69% for protein. These findings demonstrate that MOW meals currently meet the voluntary meal guidelines for energy and protein.

Effects of Substitution, and Adding of Carbohydrate and Fat to Whey-Protein on Energy Intake, Appetite, Gastric Emptying, Glucose, Insulin, Ghrelin, CCK and GLP-1 in Healthy Older Men-A Randomized Controlled Trial

Protein-rich supplements are used widely for the management of malnutrition in the elderly. We reported previously that the suppression of energy intake by whey protein is less in older than younger adults. The aim was to determine the effects of substitution, and adding of carbohydrate and fat to whey protein, on ad libitum energy intake from a buffet meal (180-210 min), gastric emptying (3D-ultrasonography), plasma gut hormone concentrations (0-180 min) and appetite (visual analogue scales), in healthy older men. In a randomized, double-blind order, 13 older men (75 ± 2 years) ingested drinks (~450 mL) containing: (i) 70 g whey protein (280 kcal; 'P₂₈₀'); (ii) 14 g protein, 28 g carbohydrate, 12.4 g fat (280 kcal; 'M₂₈₀'); (iii) 70 g protein, 28 g carbohydrate, 12.4 g fat (504 kcal; 'M₅₀₄'); or (iv) control (~2 kcal). The caloric drinks, compared to a control, did not suppress appetite or energy intake; there was an increase in total energy intake (drink + meal, p < 0.05), which was increased most by the M₅₀₄-drink. P₂₈₀- and M₅₀₄-drink ingestion were associated with slower a gastric-emptying time (n = 9), lower ghrelin, and higher cholecystokinin (CCK) and glucagon-like peptide-1 (GLP-1) than M₂₈₀ (p < 0.05). Glucose and insulin were increased most by the mixed-macronutrient drinks (p < 0.05). In conclusion, energy intake was not suppressed, compared to a control, and particularly whey protein, affected gastric emptying and gut hormone responses.

Dose-Dependent Effects of Randomized Intraduodenal Whey-Protein Loads on Glucose, Gut Hormone, and Amino Acid Concentrations in Healthy Older and Younger Men

Protein-rich supplements are used widely for the prevention and management of malnutrition in older people. We have reported that healthy older, compared to younger, adults have less suppression of energy intake by whey-protein-effects on appetite-related hormones are unknown. The objective was to determine the effects of intraduodenally administered whey-protein on glucose, gut hormone, and amino acid concentrations, and their relation to subsequent ad libitum energy intake at a buffet meal, in healthy older and younger men. Hydrolyzed whey-protein (30 kcal, 90 kcal, and 180 kcal) and a saline control (~0 kcal) were infused intraduodenally for 60 min in 10 younger (19-29 years, 73 ± 2 kg, 22 ± 1 kg/m²) and 10 older (68-81 years, 79 ± 2 kg, 26 ± 1 kg/m²) healthy men in a randomized, double-blind fashion. Plasma insulin, glucagon, gastric inhibitory peptide (GIP), glucagon-like peptide-1 (GLP-1), peptide tyrosine-tyrosine (PYY), and amino acid concentrations, but not blood glucose, increased, while ghrelin decreased during the whey-protein infusions. Plasma GIP concentrations were greater in older than younger men. Energy intake correlated positively with plasma ghrelin and negatively with insulin, glucagon, GIP, GLP-1, PYY, and amino acids concentrations (p < 0.05). In conclusion, intraduodenal whey-protein infusions resulted in increased GIP and comparable ghrelin, insulin, glucagon, GIP, GLP-1, PYY, and amino acid responses in healthy older and younger men, which correlated to subsequent energy intake.

Effect of Age on Blood Glucose and Plasma Insulin, Glucagon, Ghrelin, CCK, GIP, and GLP-1 Responses to Whey Protein Ingestion

Protein-rich supplements are used widely to prevent and manage undernutrition in older people. We have previously shown that healthy older, compared to younger, adults have less suppression of energy intake by whey protein-although the effects of age on appetite-related gut hormones are largely unknown. The aim of this study was to determine and compare the acute effects of whey protein loads on blood glucose and plasma gut hormone concentrations in older and younger adults. Sixteen healthy older (eight men, eight women; mean ± SEM: age: 72 ± 1 years; body mass index: 25 ± 1 kg/m²) and 16 younger (eight men, eight women; 24 ± 1 years; 23 ± 0.4 kg/m²) adults were studied on three occasions in which they ingested 30 g (120 kcal) or 70 g (280 kcal) whey protein, or a flavored-water control drink (~2 kcal). At regular intervals over 180 min, blood glucose and plasma insulin, glucagon, ghrelin, cholecystokinin (CCK), gastric inhibitory peptide (GIP), and glucagon-like peptide-1 (GLP-1) concentrations were measured. Plasma ghrelin was dose-dependently suppressed and insulin, glucagon, CCK, GIP, and GLP-1 concentrations were dose-dependently increased by the whey protein ingestion, while blood glucose concentrations were comparable during all study days. The stimulation of plasma CCK and GIP concentrations was greater in older than younger adults. In conclusion, orally ingested whey protein resulted in load-dependent gut hormone responses, which were greater for plasma CCK and GIP in older compared to younger adults.

Effects of Timing of Whey Protein Intake on Appetite and Energy Intake in Healthy Older Men

BACKGROUND

Protein-rich supplements are used widely to prevent and manage malnutrition in older adults. We previously showed that 30 g whey protein ingestion, 3 hours before a buffet meal, suppressed energy intake in young, but not in older men. Information about the impact of the timing of ingestion of protein drinks on the suppression of energy intake in older adults is lacking.

OBJECTIVE

The aim of the study was to determine the effect of the timing of whey protein ingestion on appetite and subsequent ad libitum energy intake in healthy older men.

DESIGN

In a single blind, randomized design, 16 older men were studied on 5 occasions, on which they consumed a whey protein drink (30 g/120 kcal, 140 mL) 3, 2, 1 hour(s), or immediately before a buffet meal, from which ad libitum energy intake was quantified, and isopalatable noncaloric drinks (∼1 kcal) at the remaining time points. On the control day, noncaloric drinks were ingested at all time points. Perceptions of appetite and gastrointestinal symptoms were determined, by visual analog scales, throughout the study days.

RESULTS

There was no effect of the timing of protein ingestion on perceptions of appetite and gastrointestinal symptoms (P > .05) or energy intake at the buffet meal (3 hours: 888 ± 49 kcal, 2 hours: 879 ± 56 kcal, 1 hours: 909 ± 47 kcal, 0 hour: 892 ± 51 kcal, control: 930 ± 49 kcal, P = .94). Total energy intake (ie, preload + test meal) was higher on the protein days compared with control (82 ± 24 kcal increase, P = .003).

CONCLUSIONS

In older men, ingestion of 30 g protein increased total energy intake, irrespective of the time of intake in relation to the meal. These observations support the use of "pure" whey protein drinks to increase overall protein and energy intake in older adults at risk of undernutrition.

Effects of randomized whey-protein loads on energy intake, appetite, gastric emptying, and plasma gut-hormone concentrations in older men and women

Background: Protein- and energy-rich supplements are used widely for the management of malnutrition in the elderly. Information about the effects of protein on energy intake and related gastrointestinal mechanisms and whether these differ between men and women is limited.Objective: We determined the effects of whey protein on energy intake, appetite, gastric emptying, and gut hormones in healthy older men and women.Design: Eight older women and 8 older men [mean ± SEM age: 72 ± 1 y; body mass index (in kg/m²): 25 ± 1] were studied on 3 occasions in which they received protein loads of 30 g (120 kcal) or 70 g (280 kcal) or a flavored water control drink (0 kcal). At regular intervals over 180 min, appetite (visual analog scales), gastric emptying (3-dimensional ultrasonography), and blood glucose and plasma gut-hormone concentrations [insulin, glucagon, ghrelin, cholecystokinin, gastric inhibitory polypeptide (GIP), glucagon-like peptide 1 (GLP-1), and peptide tyrosine tyrosine (PYY)] were measured, and ad libitum energy intake was quantified from a buffet meal (180-210 min; energy intake, appetite, and gastric emptying in the men have been published previously).Results: Energy intake at the buffet meal was ∼80% higher in older men than in older women (P < 0.001). Energy intake was not suppressed by protein compared with the control in men or women (P > 0.05). There was no effect of sex on gastric emptying, appetite, gastrointestinal symptoms, glucose, or gut hormones (P > 0.05). There was a protein load-dependent slowing of gastric emptying, an increase in concentrations of insulin, glucagon, cholecystokinin, GIP, GLP-1, and PYY, and an increase in total energy intake (drink plus meal: 12% increase with 30 g and 32% increase with 70 g; P < 0.001). Energy intake at the buffet meal was inversely related to the stomach volume and area under the curve of hormone concentrations (P < 0.05).Conclusion: In older men and women, whey-protein drinks load-dependently slow gastric emptying and alter gut hormone secretion compared with a control but have no suppressive effect on subsequent ad libitum energy intake. This trial was registered at www.anzctr.org.au as ACTRN12612000941864.

Ageing Is Associated with Decreases in Appetite and Energy Intake--A Meta-Analysis in Healthy Adults

It is not well recognized that in the elderly weight loss is more common than weight gain. The aim of this analysis was to determine the effect of ageing on appetite (hunger/fullness) and energy intake, after overnight fasting and in a postprandial state, by meta-analyses of trials that included at least two age groups (>18 years). We hypothesized that appetite and energy intake would be less in healthy older compared with younger adults. Following a PubMed-database systematic search up to 30 June 2015, 59 studies were included in the random-effects-model meta-analyses. Energy intake was 16%-20% lower in older (n = 3574/~70 years/~71 kg/~25 kg/m²) than younger (n = 4111/~26 years/~69 kg/~23 kg/m²) adults (standardized mean difference: -0.77 (95% confidence interval -0.90 to -0.64)). Hunger was 25% (after overnight fasting; weighted mean difference (WMD): -17 (-22 to -13) mm) to 39% (in a postprandial state; WMD: -14 (-19 to -9) mm) lower, and fullness 37% (after overnight fasting; WMD: 6 mm (95% CI: 1 to 11 mm)) greater in older than younger adults. In conclusion, appetite and energy intake are less in healthy older than younger adults, suggesting that ageing per se affects food intake.

Plasma Free Amino Acid Responses to Intraduodenal Whey Protein, and Relationships with Insulin, Glucagon-Like Peptide-1 and Energy Intake in Lean Healthy Men

This study determined the effects of increasing loads of intraduodenal (ID) dairy protein on plasma amino acid (AA) concentrations, and their relationships with serum insulin, plasma glucagon-like peptide-1 (GLP-1) and energy intake. Sixteen healthy men had concentrations of AAs, GLP-1 and insulin measured in response to 60-min ID infusions of hydrolysed whey protein administered, in double-blinded and randomised order, at 2.1 (P2.1), 6.3 (P6.3) or 12.5 (P12.5) kJ/min (encompassing the range of nutrient emptying from the stomach), or saline control (C). Energy intake was quantified immediately afterwards. Compared with C, the concentrations of 19/20 AAs, the exception being cysteine, were increased, and this was dependent on the protein load. The relationship between AA concentrations in the infusions and the area under the curve from 0 to 60 min (AUC0-60 min) of each AA profile was strong for essential AAs (R² range, 0.61-0.67), but more variable for non-essential (0.02-0.54) and conditional (0.006-0.64) AAs. The AUC0-60 min for each AA was correlated directly with the AUC0-60 min of insulin (R² range 0.3-0.6), GLP-1 (0.2-0.6) and energy intake (0.09-0.3) (p < 0.05, for all), with the strongest correlations being for branched-chain AAs, lysine, methionine and tyrosine. These findings indicate that ID whey protein infused at loads encompassing the normal range of gastric emptying increases plasma concentrations of 19/20 AAs in a load-dependent manner, and provide novel information on the close relationships between the essential AAs, leucine, valine, isoleucine, lysine, methionine, and the conditionally-essential AA, tyrosine, with energy intake, insulin and GLP-1.

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.

Gastric Emptying in the Elderly

Aging is characterized by a diminished homeostatic regulation of physiologic functions, including slowing of gastric emptying. Gastric and small intestinal motor and humoral mechanisms in humans are complex and highly variable: ingested food is stored, mixed with digestive enzymes, ground into small particles, and delivered as a liquefied form into the duodenum at a rate allowing efficient digestion and absorption. In healthy aging, motor function is well preserved whereas deficits in sensory function are more apparent. The effects of aging on gastric emptying are relevant to the absorption of oral medications and the regulation of appetite, postprandial glycemia, and blood pressure.

Effects of intraduodenal protein on appetite, energy intake, and antropyloroduodenal motility in healthy older compared with young men in a randomized trial

BACKGROUND

Protein-rich supplements are used widely for the prevention and management of undernutrition in older people. The use of protein supplements in older people could, however, be counterproductive by reducing appetite and overall energy intake.

OBJECTIVE

The objective was to determine whether aging influences the effects of protein loads, administered directly into the small intestine, on energy intake, antropyloroduodenal motility, and appetite.

DESIGN

Intraduodenal infusions (240 mL, 60 min) of saline (0 kcal, control) and protein (hydrolyzed whey) loads of 30, 90, and 180 kcal were followed by an ad libitum buffet meal in 10 young (19-29 y) and 10 healthy older (68-81 y) men. Suppression of energy intake (kcal) at the meal by protein infusion compared with control was calculated.

RESULTS

In young subjects, a dose-responsive suppression (±SEM) of energy intake was found at the buffet meal by protein (suppression at 30 kcal: 7 ± 8%, P = 0.189; 90 kcal: 17 ± 8%, P = 0.054; 180 kcal: 33 ± 7%, P = 0.002), whereas suppression was observed only after the 180-kcal load in older subjects (30 kcal: 7 ± 4% increase, P = 0.126; 90 kcal: 6 ± 7% increase, P = 0.291; 180 kcal: 17 ± 6% suppression, P = 0.016). Suppression of energy intake by protein was less in older than in young subjects (P < 0.005). In young subjects, total energy intake (meal + infusion) on the 180-kcal protein-infusion day was lower than that on the control day (P = 0.041), whereas in older subjects it was greater on the 30-kcal (P = 0.033) and 90-kcal (P = 0.016) infusion days. Energy intake was inversely related to isolated pyloric pressure waves (r = -0.32, P = 0.013) and positively related to antral (r = 0.30, P = 0.021) and duodenal (r = 0.35, P = 0.006) pressure waves. Suppression of energy intake by protein was inversely related to the change in isolated pyloric pressure waves (r = -0.35, P = 0.027) and positively related to duodenal pressure waves (r = 0.32, P = 0.044).

CONCLUSIONS

Intraduodenal protein suppresses appetite and energy intake less in healthy older than in young adults. In older subjects, intraduodenal protein at low doses increased overall energy intake, which supports the use of protein supplements in undernourished older people. This trial was registered at www.anzctr.org.au as 12612000906853.

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

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.

Weight-loss induced changes in physical activity and activity energy expenditure in overweight and obese subjects before and after energy restriction

Activity energy expenditure (AEE) is the component of daily energy expenditure that is mainly influenced by the amount of physical activity (PA) and by the weight of the body displaced. This study aimed at analyzing the effect of weight loss on PA and AEE. The body weight and PA of 66 overweight and obese subjects were measured at baseline and after 12 weeks of 67% energy restriction. PA was measured using a tri-axial accelerometer for movement registration (Tracmor) and quantified in activity counts. Tracmor recordings were also processed using a classification algorithm to recognize 6 common activity types engaged in during the day. A doubly-labeled water validated equation based on Tracmor output was used to estimate AEE. After weight loss, body weight decreased by 13±4%, daily activity counts augmented by 9% (95% CI: +2%, +15%), and this increase was weakly associated with the decrease in body weight (R(2) = 7%; P<0.05). After weight loss subjects were significantly (P<0.05) less sedentary (-26 min/d), and increased the time spent walking (+11 min/d) and bicycling (+4 min/d). However, AEE decreased by 0.6±0.4 MJ/d after weight loss. On average, a 2-hour/day reduction of sedentary time by increasing ambulatory and generic activities was required to restore baseline levels of AEE. In conclusion, after weight loss PA increased but the related metabolic demand did not offset the reduction in AEE due to the lower body weight. Promoting physical activity according to the extent of weight loss might increase successfulness of weight maintenance.

[Meaningful 'romming' (routine outcome monitoring): seeking a balance between userfriendliness and clinical relevance]

BACKGROUND

In the course of the last few years several ROM systems have been developed in which the measurements and feedback are restricted to the therapy outcome in terms of symptom reduction. In these ROM systems the emphasis is on the user-friendliness and on the ease with which the measurements can be implemented in clinical practice. However, research shows that many therapists and clients consider that the measurement of symptom reduction is too simplistic.

AIM

To develop a ROM system that is therapeutically more relevant.

METHOD

We describe the development and implementation of the Leuven Systematic Case study Protocol.

RESULTS

In this multidimensional and multimodal monitoring system the emphasis is on the therapeutic relevance of 'romming:' not simply in terms of symptom reduction, but also in terms of processes of change and growth-orientated processes. In addition, the monitoring system takes into account the unique characteristics of client and therapist and the synergy existing between them.

CONCLUSION

Not only do therapists have to learn to deal with the practical aspects of 'romming', they also need to be trained and supported so that they can deal adequately with a more explicit evaluation and feedback 'culture'.

Efficacy of α-lactalbumin and milk protein on weight loss and body composition during energy restriction

Our objective was to examine whether elevated α-lactalbumin (αlac) protein intake compared to elevated supra sustained milk protein (SSP) and sustained milk protein (SP) intake results into a difference in body weight and body composition over a 6-month energy-restriction intervention. Body weight, body composition, resting energy expenditure (REE), satiety and blood- and urine-parameters of 87 subjects (BMI 31 ± 5 kg/m(2) and fat percentage 40 ± 8%) were assessed before and after daily energy intakes of 100, 33, and 67% for 1, 1, and 2 months respectively (periods 1, 2, and 3), with protein intake from meal replacements and 2 months of 67% with ad libitum protein intake additional to the meal replacements (period 4). The diets resulted in 0.8 ± 0.3 g/kg body mass (BM) for SP and significant higher protein intake (24-h nitrogen) of 1.2 ± 0.3 and 1.0 ± 0.3 g/kgBM for SSP and αlac (P < 0.05). Body weight and fat percentage was decreased in all groups after 6 months (SP -7 ± 5 kg and -5 ± 3%; SSP -6 ± 3 kg and -5 ± 3%; αlac -6 ± 4 kg and -4 ± 4%, P < 0.001; there was no significant group by time difference). Furthermore, sparing of fat-free mass (FFM) and preservation of REE in function of FFM during weight loss was not significantly different between the αlac-group and the SSP- and SP-groups. In conclusion, the efficacy of αlac in reduction of body weight and fat mass (FM), and preservation of FFM does not differ from the efficacy of similar daily intakes of milk protein during 6 months of energy restriction.

Protein intake induced an increase in exercise stimulated fat oxidation during stable body weight

BACKGROUND

Protein-rich weight-loss diets spare fat-free mass at the cost of fat mass. The objective was to examine if there is a change in stimulated fat oxidation related to protein intake during stable body weight.

METHODS

Subjects' (BMI 22±2kg/m(2), age 25±8 years) maximal fat oxidation (Fat(max)) was assessed during a graded bicycle test, before and after a 3-month dietary-intervention of 2MJ/day supplements exchanged with 2MJ/d of habitual energy intake. The parallel design consisted of protein-rich supplements in the protein group and an isocaloric combination of carbohydrate and fat supplements in the control group. Daily protein intake was determined according to 24-h urine nitrogen. Body composition was measured according to a 4-compartment model by a combination of underwater-weighing technique, deuterium-dilution technique and whole-body dual-energy X-ray absorptiometry (DXA).

RESULTS

Subjects were weight stable and did not change their physical activity. The protein group (n=12) increased protein intake (11±14g, P<0.05) and had significantly higher daily protein intake vs. control (n=4) (80±21 vs.59±11g, P<0.05). Fat(max) increased significantly in the protein group (0.08±0.08g/min, P<0.01). Fat-free mass increased independent of change in body weight (P<0.01), and fat mass and fat percentage decreased (P<0.05). Change in Fat(max) was a function of change in protein intake (r=0.623, P<0.05), and not of changes in body composition or VO(2)max.

CONCLUSION

Increased stimulated fat oxidation was related to increased protein intake.

No long-term weight maintenance effects of gelatin in a supra-sustained protein diet

In the short-term, gelatin showed stronger hunger suppression and less energy intake compared with other proteins. This study investigated if a supra-sustained gelatin-milk protein (GMP) diet improves weight maintenance (WM) compared with a sustained milk protein (SMP) diet and supra-sustained milk protein (SSMP) diet during a 4-months WM period after 8-week weight loss (WL) in sixty-five healthy subjects (28.6+/-3.4kg/m(2); 44+/-10years). Absolute protein intake was kept constant (sustained) throughout per subject. Diets were: protein(P)/fat(F)/carbohydrate(C): 15/40/45% of energy (En%) (SMP) and 30/25/45 En% (SSMP or GMP) for weeks 9-16. Diets on weeks 17-24: P/F/C: 30/35/35 En% (SMP) and 60/5/35 En% (SSMP or GMP). From weeks 8 to 16, and weeks 16 to 24, changes in BMI were similar between the GMP (-0.4+/-0.6 and 0.3+/-0.7kg/m(2) respectively), and the SMP (-0.7+/-0.9 and 0.1+/-0.7kg/m(2) respectively) and SSMP (-0.6+/-0.6 and 0.3+/-0.6kg/m(2) respectively) diets. Sparing of fat free mass (FFM): increases/decreases in FFM%/fat-mass% from weeks 8 to 16 were similar between the GMP and both control diets, and maintained from weeks 16 to 24. In conclusion, all 3 diets resulted in a successful WM period, while a GMP diet does not improve body weight maintenance and related variables after weight loss compared with a SMP and SSMP diet.

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.

Proteins and satiety: implications for weight management

PURPOSE OF REVIEW

To highlight the satiating background and effects of proteins and their implications for weight management.

RECENT FINDINGS

The satiating effect of protein is the key player in body-weight loss and body-weight maintenance thereafter. Specific high-protein meals or high-protein diets induced satiety require a realistic bandwidth of energy intake, protein concentrations, texture, and timing of assessment of effects. Satiety is nutrient specifically supported by elevated amino acid concentrations, responses of anorexigenic hormones or protein-induced energy expenditure. During long-term high-protein diets sustained satiety, energy expenditure, and sparing fat-free body mass are essential. For effects due to satiety, ad libitum energy intake conditions are necessary. Adverse events related to kidney damage may occur with sulphur-containing amino acids; individuals with obesity, metabolic syndrome and diabetes mellitus II may be susceptible groups.

SUMMARY

Highly controlled medium-term studies overcoming possible differences due to texture, timing and macronutrient exchange, and assessing satiety, energy expenditure and substrate oxidation at the same time, need to be executed with a realistic bandwidth of different types of proteins in overweight individuals in different energy balances.

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.

Insulin acutely upregulates protein expression of the fatty acid transporter CD36 in human skeletal muscle in vivo

Enhanced fatty acid uptake may lead to the accumulation of lipid intermediates. This is related to insulin resistance and type 2 diabetes mellitus. Rodent studies suggest that fatty acid transporters are acutely regulated by insulin. We investigated differences in fatty acid transporter content before and at the end of a hyperinsulinemic euglycemic clamp in skeletal muscle (m. vastus lateralis) of obese, glucose-intolerant men (IGT) and obese normal glucose tolerant controls (NGT). The fatty acid transporter FAT/CD36 protein content increased 1.5-fold (P < 0.05) after 3-hrs of insulin stimulation with no difference between IGT and control subjects. No change was seen in cytosolic fatty acid binding protein (FABPc) protein content. The increase in FAT/CD36 protein content was positively related to insulin resistance as measured during the clamp (r = 0.56, P < 0.05). An increase in FAT/CD36 protein content in skeletal muscle may result in a higher fractional extraction of fatty acids (larger relative uptake) after a meal, enhancing triglyceride accumulation in the muscle. We conclude that also in obese humans the FAT/CD36 protein content in skeletal muscle is dynamically regulated by insulin in vivo on the short term.

Protein-induced satiety: effects and mechanisms of different proteins

Relatively high protein diets, i.e. diets that maintain the absolute number of grams of protein ingested as compared to before dieting, are a popular strategy for weight loss and weight maintenance. Research into multiple mechanisms regulating body weight has focused on the effects of different quantities and types of dietary protein. Satiety and energy expenditure are important in protein-enhanced weight loss and weight maintenance. Protein-induced satiety has been shown acutely, with single meals, with contents of 25% to 81% of energy from protein in general or from specific proteins, while subsequent energy intake reduction was significant. Protein-induced satiety has been shown with high protein ad libitum diets, lasting from 1 to 6 days, up to 6 months. Also significantly greater weight loss has been observed in comparison with control. Mechanisms explaining protein-induced satiety are nutrient-specific, and consist mainly of synchronization with elevated amino acid concentrations. Different proteins cause different nutrient related responses of (an)orexigenic hormones. Protein-induced satiety coincides with a relatively high GLP-1 release, stimulated by the carbohydrate content of the diet, PYY release, while ghrelin does not seem to be especially affected, and little information is available on CCK. Protein-induced satiety is related to protein-induced energy expenditure. Finally, protein-induced satiety appears to be of vital importance for weight loss and weight maintenance. With respect to possible adverse events, chronic ingestion of large amounts of sulphur-containing amino acids may have an indirect effect on blood pressure by induction of renal subtle structural damage, ultimately leading to loss of nephron mass, and a secondary increase in blood pressure. The established synergy between obesity and low nephron number on induction of high blood pressure and further decline of renal function identifies subjects with obesity, metabolic syndrome and diabetes mellitus II as particularly susceptible groups.