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.Natalie D. Luscombe-Marsh, Amy T. Hutchison, Stijn Soenen, Robert E. Steinert, Peter M. Clifton, Michael Horowitz and Christine Feinle-Bisse

A cross-sectional study of nutrient intake and health status among older adults in Yogyakarta Indonesia

Many communities around the world, particularly developing countries including Indonesia, are experiencing population ageing. There is little knowledge regarding the impact of malnutrition, or its prevalence within rural compared to urban areas, on the nutritional, functional and mental status of community-living older residents in these countries. Hence, a cross-sectional study was conducted to determine socio-demographic and anthropometric characteristics, nutritional, mental and functional status, and energy and nutrient intake of community-dwelling Indonesians from both rural and urban areas of Yogyakarta. Older individuals were included in the study if they had been living in Yogyakarta for the last year and were aged ≥65 years (n = 527; mean ± SD age of 74 ± 7 years). Rural compared with urban participants had a lower level of education and income, more hospital admissions, less dietary protein intake, lower cognitive function, poorer nutritional status and grip strength, but faster gait speed while being more dependent on assistance to perform daily activities (all p < 0.05). Cognitive function was more strongly associated than nutritional status with physical function. Rural older Indonesians living in Yogyakarta were more likely than urban older people to be malnourished and cognitively impaired, and to have associated reductions in functional capacity and independence. Strategies to improve cognitive function and nutritional status are therefore important for the wellbeing of Indonesian citizens.Tony Arjuna, Stijn Soenen, Rasita Amelia Hasnawati, Kylie Lange, Ian Chapman and Natalie D. Luscombe-Mars

Long-term effects of a very low carbohydrate compared with a high carbohydrate diet on renal function in individuals with type 2 diabetes: a randomized trial

To compare the long-term effects of a very low carbohydrate, high-protein, low saturated fat (LC) diet with a traditional high unrefined carbohydrate, low-fat (HC) diet on markers of renal function in obese adults with type 2 diabetes (T2DM), but without overt kidney disease.One hundred fifteen adults (BMI 34.6 ± 4.3 kg/m, age 58 ± 7 years, HbA1c 7.3 ± 1.1%, 56 ± 12 mmol/mol, serum creatinine (SCr) 69 ± 15 μmol/L, glomerular filtration rate estimated by the Chronic Kidney Disease Epidemiology Collaboration formula (eGFR 94 ± 12 mL/min/1.73 m)) were randomized to consume either an LC (14% energy as carbohydrate [CHO < 50 g/day], 28% protein [PRO], 58% fat [<10% saturated fat]) or an HC (53% CHO, 17% PRO, 30% fat [<10% saturated fat]) energy-matched, weight-loss diet combined with supervised exercise training (60 min, 3 day/wk) for 12 months. Body weight, blood pressure, and renal function assessed by eGFR, estimated creatinine clearance (Cockcroft-Gault, Salazar-Corcoran) and albumin excretion rate (AER), were measured pre- and post-intervention.Both groups achieved similar completion rates (LC 71%, HC 65%) and reductions in weight (mean [95% CI]; -9.3 [-10.6, -8.0] kg) and blood pressure (-6 [-9, -4]/-6[-8, -5] mmHg), P ≥ 0.18. Protein intake calculated from 24 hours urinary urea was higher in the LC than HC group (LC 120.1 ± 38.2 g/day, 1.3 g/kg/day; HC 95.8 ± 27.8 g/day, 1 g/kg/day), P < 0.001 diet effect. Changes in SCr (LC 3 [1, 5], HC 1 [-1, 3] μmol/L) and eGFR (LC -4 [-6, -2], HC -2 [-3, 0] mL/min/1.73 m) did not differ between diets (P = 0.25). AER decreased independent of diet composition (LC --2.4 [-6, 1.2], HC -1.8 [-5.4, 1.8] mg/24 h, P = 0.24); 6 participants (LC 3, HC 3) had moderately elevated AER at baseline (30-300 mg/24 h), which normalized in 4 participants (LC 2, HC 2) after 52 weeks.Compared with a traditional HC weight loss diet, consumption of an LC high protein diet does not adversely affect clinical markers of renal function in obese adults with T2DM and no preexisting kidney disease.Jeannie Tay, Campbell H. Thompson, Natalie D. Luscombe-Marsh, Manny Noakes, Jonathan D. Buckley, Gary A. Wittert and Grant D. Brinkwort

Food services using energy- and protein-fortified meals to assist vulnerable community-residing older adults meet their dietary requirements and maintain good health and quality of life: findings from a pilot study

The effects of "standard (STD)" vs. "protein- and energy-enriched (HEHP)" food-service meals on the nutrient intake, nutritional status, functional capacity, and wellbeing of older adults was investigated using a 12 week, double-blinded, parallel group design. All participants received dietetics counseling and either an STD (2.3 MJ and 30 g protein per meal) or a HEHP (4.6 MJ and 60 g protein) hot lunchtime meal for at least 3 days/week; those who did not want food-service meals were included in the control group (CON). Twenty-nine participants completed the study (STD = 7; HEHP = 12; CON = 10). From baseline to week 12, the HEHP subjects increased their mean daily energy intake from 6151 ± 376 kJ to 8228 ± 642 kJ (p = 0.002 for effect of time) and protein intake from 67 ± 4 g to 86 ± 8 g (p = 0.014 for effect of time). The MNA (Mini Nutritional Assessment) score was increased significantly in HEHP by 4.0 ± 1.1 points (p = 0.001), but not in the STD and CON groups (2.8 ± 2.1 points and 1.8 ± 1.1 points, p > 0.05). No difference was found for other clinical outcomes between the groups. The findings indicate that provision of HEHP-fortified food-service meals can increase energy and protein intake and improve the nutritional status of nutritionally at-risk older people.Tony Arjuna, Michelle Miller, Tomoko Ueno, Renuka Visvanathan, Kylie Lange, Stijn Soenen, Ian Chapman and Natalie Luscombe-Mars

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.Caroline Giezenaar, Natalie D Luscombe-Marsh, Amy T Hutchison, Scott Standfield, Christine Feinle-Bisset, Michael Horowitz, Ian Chapman and Stijn Soene

Protein and Overtraining: Potential Applications for Free-Living Athletes

Despite a more than adequate protein intake in the general population, athletes have special needs and situations that bring it to the forefront. Overtraining is one example. Hard-training athletes are different from sedentary persons from the sub-cellular to whole-organism level. Moreover, competitive, "free-living" (less-monitored) athletes often encounter negative energy balance, sub-optimal dietary variety, injuries, endocrine exacerbations and immune depression. These factors, coupled with "two-a-day" practices and in-season demands require that protein not be dismissed as automatically adequate or worse, deleterious to health. When applying research to practice settings, one should consider methodological aspects such as population specificity and control variables such as energy balance. This review will address data pertinent to the topic of athletic protein needs, particularly from a standpoint of overtraining and soft tissue recovery. Research-driven strategies for adjusting nutrition and exercise assessments will be offered for consideration. Potentially helpful nutrition interventions for preventing and treating training complications will also be presented

Parasite Burden and CD36-Mediated Sequestration Are Determinants of Acute Lung Injury in an Experimental Malaria Model

Although acute lung injury (ALI) is a common complication of severe malaria, little is known about the underlying molecular basis of lung dysfunction. Animal models have provided powerful insights into the pathogenesis of severe malaria syndromes such as cerebral malaria (CM); however, no model of malaria-induced lung injury has been definitively established. This study used bronchoalveolar lavage (BAL), histopathology and gene expression analysis to examine the development of ALI in mice infected with Plasmodium berghei ANKA (PbA). BAL fluid of PbA-infected C57BL/6 mice revealed a significant increase in IgM and total protein prior to the development of CM, indicating disruption of the alveolar–capillary membrane barrier—the physiological hallmark of ALI. In contrast to sepsis-induced ALI, BAL fluid cell counts remained constant with no infiltration of neutrophils. Histopathology showed septal inflammation without cellular transmigration into the alveolar spaces. Microarray analysis of lung tissue from PbA-infected mice identified a significant up-regulation of expressed genes associated with the gene ontology categories of defense and immune response. Severity of malaria-induced ALI varied in a panel of inbred mouse strains, and development of ALI correlated with peripheral parasite burden but not CM susceptibility. Cd36−/− mice, which have decreased parasite lung sequestration, were relatively protected from ALI. In summary, parasite burden and CD36-mediated sequestration in the lung are primary determinants of ALI in experimental murine malaria. Furthermore, differential susceptibility of mouse strains to malaria-induced ALI and CM suggests that distinct genetic determinants may regulate susceptibility to these two important causes of malaria-associated morbidity and mortality

Diets high and low in glycemic index versus high monounsaturated fat diets: effects on glucose and lipid metabolism in NIDDM

ObjectiveTo examine the relative effects of high and low glycemic index (GI) carbohydrates, and monounsaturated fats on blood glucose and lipid metabolism in NIDDM subjects.SubjectsFourteen male and seven female variably controlled NIDDM subjects recruited by advertisement.SettingFree living outpatients.Research designA repeated measures, within-subject design was used such that each subject consumed three diets: (a) a high-GI diet (53% CHO -21% fat, 63 GI units (glucose= 100)); (b) a low-GI diet (51% CHO -23% fat, 43 GI units); and (c) a high-mono high-GI diet (42% CHO -35% fat, 59 GI units) in random order and cross-over fashion for four weeks. Approximately 45% energy was provided as key foods which differed in published GI values and specifically excluded legumes. Dietary fibre intake was > 30 g/d on each diet. At the end of each dietary intervention, we measured fasting plasma lipids, glucose, insulin, total glycated plasma protein, fructosamine, LDL and HDL particle size as well as 24 h urinary excretion of glucose and C-peptide.ResultsHDL-cholesterol was higher on the low-GI and high-mono high-GI diets compared to the high-GI diet (P ConclusionHigh-mono high-GI and high-CHO, low-GI diets are superior to high-CHO, high-GI diets with respect to HDL metabolism but no effect was noted on glucose metabolism in variably controlled NIDDM subjects

Monosodium glutamate is not associated with obesity or a greater prevalence of weight gain over 5 years: findings from the Jiangsu Nutrition Study of Chinese adults - response

Zumin Shi, Natalie D. Luscombe-Marsh, Gary A. Wittert and Anne W. Taylo