Search

Background A chronic low-grade inflammatory profile (CLIP) is associated with sarcopenia in older adults. Protein and Vitamin (Vit)D have immune-modulatory potential, but evidence for effects of nutritional supplementation on CLIP is limited. Aim To investigate whether 13 weeks of nutritional supplementation of VitD and leucine-enriched whey protein affected CLIP in subjects enrolled in the PROVIDE-study, as a secondary analysis. Methods Sarcopenic adults (low skeletal muscle mass) aged ≥ 65 years with mobility limitations (Short Physical Performance Battery 4–9) and a body mass index of 20–30 kg/m2 were randomly allocated to two daily servings of active (n = 137, including 20 g of whey protein, 3 g of leucine and 800 IU VitD) or isocaloric control product (n = 151) for a double-blind period of 13 weeks. At baseline and after 13 weeks, circulating interleukin (IL)-8, IL-1 receptor antagonist (RA), soluble tumor-necrosis-factor receptor (sTNFR)1, IL-6, high-sensitivity C-reactive protein, pre-albumin and 25-hydroxyvitamin(OH)D were measured. Data-analysis included repeated measures analysis of covariance (corrected for dietary VitD intake) and linear regression. Results IL-6 and IL-1Ra serum levels showed overall increases after 13 weeks (p = 0.006 and p

Introduction In 2008, the NutriAction study showed that (risk of) malnutrition was highly prevalent (57%) among Belgian older people living in the community or in a nursing home. In 2013, this study was repeated to re-evaluate the occurrence of malnutrition, as well as mobility problems and dependence in activities of daily living (ADL). Methods Health care professionals (HCPs) associated with homecare organizations and nursing homes across Belgium were invited to screen their patients and complete an online questionnaire. Nutritional status, presence of pre-specified comorbidities, mobility, and ADL dependency were assessed. Results In total, 3299 older patients were analysed: 2480 (86.3 ± 6.3 years) nursing home (NH) residents and 819 (82.7 ± 6.1 years) community dwelling (CD). Overall, 12% was malnourished (MNA-SF score

Background & aims: It has been suggested that anabolic resistance, or a blunted protein synthetic response to anabolic stimuli, contributes to the failure of muscle mass maintenance in older adults. The amino acid leucine is one of the most prominent food-related anabolic stimuli. However, data on muscle protein synthesis (MPS) after administration of a single bolus of leucine in aged populations is lacking and long-term single leucine supplementation has not been shown to increase muscle mass. This study aimed to determine the MPS response to the administration of a single bolus of leucine or to leucine combined with whey protein, in aged mice.Methods: Overnight fasted C57/BL6RJ mice at 25-mo of age received an oral gavage with leucine or whey-protein enriched with leucine (0.75 g/kg bodyweight total leucine in both) or 0.5 mL water (fasted control). Subsequently, mice were s.c. injected with puromycin (0.04 mu mol/g bw at t = 30, 45 or 60 min) and were sacrificed 30 min thereafter. Amino acid concentrations were determined in plasma and right muscle tibialis anterior (TA). Left TA was used to analyse MPS by SUnSET method and phosphorylation rate of Akt, 4E-BP1 and p70S6k by western blot.Results: In aged mice, leucine administration failed to increase MPS, despite a 6-fold increase in plasma leucine and elevated muscle free leucine levels (P Conclusions: MPS is stimulated in aged mice by leucine-enriched whey protein but not by leucine administration only. Administration of other amino acids may be required for leucine administration to stimulate muscle protein synthesis in aged mice. (c) 2018 Nutricia Research. Published by Elsevier Ltd on behalf of European Society for Clinical Nutrition and Metabolism.

BACKGROUND & AIMS: The requirement of leucine and essential amino acids (EAA) to stimulate muscle protein synthesis increases with age. To target muscle anabolism it is suggested that higher postprandial blood levels of leucine and EAA are needed in older people. The aim was to evaluate the impact of oral nutritional supplements with distinct protein source and energy density, resembling mixed meals, on serum amino acid profiles and on gastrointestinal behaviour. METHODS: Four iso-nitrogenous protein (21 g) supplements were studied containing leucine-enriched whey protein with 150/320 kcal (W150/W320) or casein protein with 150/320 kcal (C150/C320); all products contained carbohydrates (10 or 32 g) and fat (3 or 12 g). Postprandial serum AA profiles were evaluated in twelve healthy, older subjects who participated in a randomized, controlled, single blind, cross-over study. Gastrointestinal behaviour was studied in vitro by looking at gastric coagulation and cumulative intestinal protein digestion over time. RESULTS: The peak serum leucine concentration was twofold higher for W150 vs. C150 (521 +/- 15 vs. 260 +/- 15 mumol/L, p < 0.001), higher for W320 vs. C320 (406 +/- 15 vs. 228 +/- 15 mumol/L, p < 0.001), and higher for low-caloric vs. high-caloric products (p < 0.001 for pooled analyses; p < 0.001 for interaction protein source*caloric density). Similar effects were observed for the peak concentrations of EAA and total AA (TAA). In vitro gastric coagulation was observed only for the casein protein supplements. Intestinal digestion for 90 min resulted in higher levels of free TAA, EAA, and leucine for W150 vs. C150, for W150 vs. W320, and for C150 vs. C320 (p < 0.0125). CONCLUSIONS: A low caloric leucine-enriched whey protein nutritional supplement provides a higher rise in serum levels of TAA, EAA and leucine compared to casein protein or high caloric products in healthy, elderly subjects. These differences appear to be mediated in part by the gastrointestinal behaviour of these products. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov: NCT02013466.

Background: Studying the muscle protein synthetic response to food intake in elderly is important, as it aids the development of interventions to combat sarcopenia. Although sarcopenic elderly are the target group for many of these nutritional interventions, no studies have assessed basal or post-prandial muscle protein synthesis rates in this population.Objective: To assess the basal and post-prandial muscle protein synthesis rates between healthy and sarcopenic older men.Design: A total of 15 healthy (69 +/- 1 y) and 15 sarcopenic (81 +/- 1 y) older men ingested a leucine-enriched whey protein nutritional supplement containing 21 g of protein, 9 g of carbohydrate, and 3 g of fat. Stable isotope methodology combined with frequent collection of blood and muscle samples was applied to assess basal and post-prandial muscle protein fractional synthetic rates. Handgrip strength, muscle mass, and gait speed were assessed to identify sarcopenia, according to international criteria. Results: Basal mixed muscle protein fractional synthetic rates (FSR) averaged 0.040 +/- 0.005 and 0.032 +/- 0.003%/h (mean +/- SEM) in the sarcopenic and healthy group, respectively (P = 0.14). Following protein ingestion, FSR increased significantly to 0.055 +/- 0.004 and 0.053 +/- 0.004%/h in the post-prandial period in the sarcopenic (P = 0.003) and healthy groups (P Conclusions: Basal muscle protein synthesis rates are not lower in sarcopenic older men compared to healthy older men. The ingestion of 21 g of a leucine-enriched whey protein effectively increases muscle protein synthesis rates in both sarcopenic and healthy older men. (C) 2016 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

ScopeIn recent years, there has been a growing body of evidence pointing to an effect of vitamin D on muscle mass and function. Our aim was to investigate the combined effect of 1,25(OH)(2)-vitamin D-3 (1,25(OH)(2)D-3) with anabolic factors insulin and leucine on protein fractional synthesis rate (FSR) and regulation in the mouse C2C12 myotube. Methods and resultsAfter differentiation, myotubes were cultured in 1,25(OH)(2)D-3 solutions at 0, 1, or 10 nM for 72 h. Cells were treated by l-[1-C-13]valine and puromycin in presence or not of leucine and insulin, and protein FSR was determined by measuring tracer enrichments and puromycin incorporation in proteins, respectively. Protein expression and phosphorylation state of insulin receptor (IR), Akt, GSK3, mTOR, p70 S6 kinase, rpS6, and 4EBP1 were measured by Western blot. Transcript levels of IR and 1,25(OH)(2)D-3 receptor (VDR) were determined by qPCR. 1,25(OH)(2)D-3 (10 nM) with leucine and insulin increased protein FSR in C2C12 myotubes (14-16%). IR and VDR mRNA expression was increased with 1,25(OH)(2)D-3 treatment. The Akt/mTOR-dependent pathway was activated by insulin and leucine and further enhanced by 1,25(OH)(2)D-3. Conclusion1,25(OH)(2)D-3 sensitizes the Akt/mTOR-dependant pathway to the stimulating effect of leucine and insulin, resulting in a further activation of protein synthesis in murine C2C12 skeletal myotubes.

Decreased ability of muscles to respond to anabolic stimuli is part of the underlying mechanism for muscle loss with aging. Previous studies suggest that substantial amounts of essential amino acids (EAA), whey protein and leucine are beneficial for stimulation of acute muscle protein synthesis in older adults. However, these studies supplied only proteins, and no bolus studies have been done with dairy products or supplements that contained also fat and carbohydrates besides proteins. The aim of this study was to evaluate whether a specifically designed nutritional supplement in older adults stimulates muscle protein synthesis acutely to a greater extent than a conventional dairy product. Moreover, the combined effect with resistance exercise was studied by using a unilateral resistance exercise protocol. Utilizing a randomized, controlled, double blind study design, healthy older adults received a single bolus of a high whey protein, leucine-enriched supplement (EXP: 20g whey protein, 3g total leucine, 150kcal; n = 9) or an iso-caloric milk protein control (Control: 6g milk protein; n = 10), immediately after unilateral resistance exercise. Postprandial mixed muscle protein fractional synthesis rate (FSR) was measured over 4h using a tracer infusion protocol with L-[ring-13C6]-phenylalanine and regular blood and muscle sampling. FSR was significantly higher overall after EXP (0.0780 ± 0.0070%/h) vs Control (0.0574 ± 0.0066%/h (EMM ± SE)) (p = 0.049). No interaction between treatment and exercise was observed (p = 0.519). Higher postprandial concentrations of EAA and leucine are possible mediating factors for the FSR response, while plasma insulin increase did not dictate the FSR response. Moreover, when the protein intake from the supplements was expressed per kg leg lean mass (LLM), a significant correlation was observed with resting postprandial FSR (r = 0.48, P = 0.038). Ingestion of a high whey protein, leucine-enriched supplement resulted in a larger overall postprandial muscle protein synthesis rate in healthy older subjects compared with a conventional dairy product. This acute effect is promising for long-term effects on parameters of muscle mass, strength and function in sarcopenic older people, which requires further study. This trial is registered in the Dutch Trial Register under number NTR1823 .