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Nutritional counseling frequency and baseline food pattern predict implementation of a high-protein and high-polyunsaturated fatty acid dietary pattern: 1-year results of the randomized NutriAct trial.
Pletsch-Borba, L, Wernicke, C, Apostolopoulou, K, Spira, D, Pohrt, A, Hornemann, S, Gerbracht, C, Pfeiffer, AFH, Spranger, J, Mai, K
Clinical nutrition (Edinburgh, Scotland). 2021;(11):5457-5466
Abstract
BACKGROUND & AIMS NutriAct is a 36-month randomized controlled multi-center trial designed to analyze the effects of a food pattern focusing on a high-protein and high-unsaturated fatty acids (UFA) intake on healthy aging. We aimed to determine factors associated with a successful modulation of dietary pattern after 12 months in elderly participants. METHODS 502 participants were randomized into either usual care control group including dietary recommendations of the German Nutrition Society (DGE) or an intervention group, which used supplementation of rapeseed oil and specifically designed foods as well as repetitive advices to implement a food pattern based on high intake of predominantly plant proteins, UFA and fiber (NutriAct pattern). Food intake was repeatedly assessed by 3-day food records at months 0, 3, 6 and 12. Linear regression models were used to investigate determinants of basal food intake and modulation of dietary pattern during the intervention. RESULTS Food records of 242 intervention and 246 control participants (median age 66 y, 37% males) were available at baseline and were included. At baseline, high BMI was related to higher protein and saturated fatty acids and lower fiber intake. The intervention resulted in higher intake of protein, mono- and polyunsaturated fatty acids (MUFA and PUFA) and fiber, and lower carbohydrate and saturated fatty acid consumption (all p < 0.001). While individuals who were already at baseline closer to the NutriAct pattern also achieved a diet closer to the proposed pattern at month 12, the strongest absolute changes (%E) of dietary behavior were seen in those with dietary patterns further away from the proposed pattern at baseline. Attendance to nutritional sessions was crucial to change MUFA, PUFA, fiber and carbohydrate intake. CONCLUSIONS A successful modification of dietary pattern was achieved by the performed intervention within 12 months. Baseline dietary habits and attendance to nutritional sessions were substantial determinants predicting changes in dietary pattern. CLINICAL TRIAL REGISTRATION The trial was registered at German Clinical Trials Register (drks.de) as DRKS00010049.
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Rationale and Design for a Higher (Dairy) Protein Weight Loss Intervention That Promotes Muscle Quality and Bone Health in Older Adults with Obesity: A Randomized, Controlled Pilot Study.
Miller, MG, Porter Starr, KN, Rincker, J, Orenduff, MC, McDonald, SR, Pieper, CF, Fruik, AR, Lyles, KW, Bales, CW
Journal of nutrition in gerontology and geriatrics. 2021;(2-3):150-170
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Abstract
In contrast to recommendations for young and middle-aged adults, intentional weight loss among older adults remains controversial and is inconsistently advised. Recent research suggests that a higher protein diet can mitigate loss of lean mass during periods of intentional weight loss among older adults with obesity; however, the effects of intentional weight loss on skeletal muscle and bone are not fully understood. The Dairy in the Diet Yields New Approaches for Muscle Optimization (DDYNAMO) trial is a 6-month, randomized, controlled pilot study assessing the effects of combining regular, generous intakes of high quality protein (30 g/meal; primarily from dairy) with caloric restriction (-500kcal/d) and low-intensity resistance exercise (30 min/3 times per week) on muscle quality, muscle composition, bone mineral density in men and women aged ≥60 years with obesity and mild to moderate functional impairment (Short Physical Performance Battery [SPPB] score ≥4 to ≤10). Participants will be re-assessed at 18 months to evaluate weight maintenance, bone mineral density, physical function, and other secondary measures. ClinicalTrials.gov Identifier: NCT02437643.
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Effect of Protein Intake on Visceral Abdominal Fat and Metabolic Biomarkers in Older Men With Functional Limitations: Results From a Randomized Clinical Trial.
Huang, G, Pencina, K, Li, Z, Apovian, CM, Travison, TG, Storer, TW, Gagliano-Jucá, T, Basaria, S, Bhasin, S
The journals of gerontology. Series A, Biological sciences and medical sciences. 2021;(6):1084-1089
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BACKGROUND It remains controversial whether high protein diets improve cardiometabolic profile. We investigated whether increasing protein intake to 1.3 g/kg/day in functionally limited older adults with usual protein intake ≤RDA (0.8 g/kg/day) improves visceral fat accumulation and serum cardiovascular risk markers more than the recommended daily allowance (RDA). METHODS The Optimizing Protein Intake in Older Men Trial was a placebo-controlled, randomized trial in which 92 functionally limited men, ≥65 years, with usual protein intake ≤RDA were randomized for 6 months to: 0.8 g/kg/day protein plus placebo; 1.3 g/kg/day protein plus placebo; 0.8 g/kg/day protein plus testosterone enanthate 100 mg weekly; or 1.3 g/kg/day protein plus testosterone enanthate 100 mg weekly. In this substudy, metabolic and inflammatory serum markers were measured in 77 men, and visceral adipose tissue (VAT) was assessed using dual-energy x-ray absorptiometry in 56 men. RESULTS Treatment groups were similar in their baseline characteristics. Randomization to 1.3 g/kg/day protein group was associated with greater reduction in VAT compared to 0.8 g/kg/day group (between-group difference: -17.3 cm2, 95% confidence interval [CI]: -29.7 to -4.8 cm2, p = .008), regardless of whether they received testosterone or placebo. Changes in fasting glucose, fasting insulin, HOMA-IR, leptin, adiponectin, IL-6, and hs-CRP did not differ between the 0.8 versus 1.3 g/kg/day protein groups regardless of testosterone use. CONCLUSIONS Protein intake >RDA decreased VAT in functionally limited older men but did not improve cardiovascular disease risk markers. CLINICAL TRIALS REGISTRATION NUMBER NCT01275365.
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Glucagon-like peptide-1 regulation by food proteins and protein hydrolysates.
Miguéns-Gómez, A, Casanova-Martí, À, Blay, MT, Terra, X, Beltrán-Debón, R, Rodríguez-Gallego, E, Ardévol, A, Pinent, M
Nutrition research reviews. 2021;(2):259-275
Abstract
Glucagon-like peptide-1 (GLP-1) is an enterohormone with a key role in several processes controlling body homeostasis, including glucose homeostasis and food intake regulation. It is secreted by the intestinal cells in response to nutrients, such as glucose, fat and amino acids. In the present review, we analyse the effect of protein on GLP-1 secretion and clearance. We review the literature on the GLP-1 secretory effects of protein and protein hydrolysates, and the mechanisms through which they exert these effects. We also review the studies on protein from different sources that has inhibitory effects on dipeptidyl peptidase-4 (DPP4), the enzyme responsible for GLP-1 inactivation, with particular emphasis on specific sources and treatments, and the gaps there still are in knowledge. There is evidence that the protein source and the hydrolytic processing applied to them can influence the effects on GLP-1 signalling. The gastrointestinal digestion of proteins, for example, significantly changes their effectiveness at modulating this enterohormone secretion in both in vivo and in vitro studies. Nevertheless, little information is available regarding human studies and more research is required to understand their potential as regulators of glucose homeostasis.
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Protein-saliva interactions: a systematic review.
Brown, FN, Mackie, AR, He, Q, Branch, A, Sarkar, A
Food & function. 2021;(8):3324-3351
Abstract
Food industries are challenged to reformulate foods and beverages with higher protein contents to lower fat and sugar content. However, increasing protein concentration can reduce sensory acceptability due to astringency perception. Since the properties of food-saliva mixtures govern mouthfeel perception, understanding how saliva and protein interact is key to guide development of future protein-rich reformulations with optimal sensory attributes. Hence, this systematic review investigated protein-saliva interaction using both model and real human saliva, including a quality assessment. A literature search of five databases (Medline, Pubmed, Embase, Scopus and Web of Science) was undertaken covering the last 20 years, yielding 36 604 articles. Using pre-defined criteria, this was reduced to a set of 33 articles with bulk protein solutions (n = 17), protein-stabilized emulsions (n = 13) and protein-rich food systems (n = 4). Interaction of dairy proteins, lysozyme and gelatine with model or human saliva dominated the literature. The pH was shown to have a strong effect on electrostatic interaction of proteins with negatively-charged salivary mucins, with greater interactions occurring below the isoelectric point of proteins. The effect of protein concentration was unclear due to the limited range of concentrations being studied. Most studies employed a 1 : 1 w/w protein : saliva ratio, which is not representative of true oral conditions. The interaction between protein and saliva appears to affect mouthfeel through aggregation and increased friction. The searches identified a gap in research on plant proteins. Accurate simulation of in vivo oral conditions should clarify understanding of protein-saliva interaction and its influence on sensory perception.
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The Effect of Elevated Protein Intake on DNA Damage in Older People: Comparative Secondary Analysis of Two Randomized Controlled Trials.
Draxler, A, Franzke, B, Cortolezis, JT, Gillies, NA, Unterberger, S, Aschauer, R, Zöhrer, PA, Bragagna, L, Kodnar, J, Strasser, EM, et al
Nutrients. 2021;(10)
Abstract
A high protein intake at old age is important for muscle protein synthesis, however, this could also trigger protein oxidation with the potential risk for DNA damage. The aim of this study was to investigate whether an increased protein intake at recommended level or well above would affect DNA damage or change levels of reduced (GSH) and oxidised glutathione (GSSG) in community-dwelling elderly subjects. These analyses were performed in two randomized intervention studies, in Austria and in New Zealand. In both randomized control trials, the mean protein intake was increased with whole foods, in the New Zealand study (n = 29 males, 74.2 ± 3.6 years) to 1.7 g/kg body weight/d (10 weeks intervention; p < 0.001)) in the Austrian study (n = 119 males and females, 72.9 ± 4.8 years) to 1.54 g/kg body weight/d (6 weeks intervention; p < 0.001)). In both studies, single and double strand breaks and as formamidopyrimidine-DNA glycosylase-sensitive sites were investigated in peripheral blood mononuclear cells or whole blood. Further, resistance to H2O2 induced DNA damage, GSH, GSSG and CRP were measured. Increased dietary protein intake did not impact on DNA damage markers and GSH/GSSG levels. A seasonal-based time effect (p < 0.05), which led to a decrease in DNA damage and GSH was observed in the Austrian study. Therefore, increasing the protein intake to more than 20% of the total energy intake in community-dwelling seniors in Austria and New Zealand did not increase measures of DNA damage, change glutathione status or elevate plasma CRP.
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Dietary protein intake does not modulate daily myofibrillar protein synthesis rates or loss of muscle mass and function during short-term immobilization in young men: a randomized controlled trial.
Kilroe, SP, Fulford, J, Jackman, S, Holwerda, A, Gijsen, A, van Loon, L, Wall, BT
The American journal of clinical nutrition. 2021;(3):548-561
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BACKGROUND Short-term (<1 wk) muscle disuse lowers daily myofibrillar protein synthesis (MyoPS) rates resulting in muscle mass loss. The understanding of how daily dietary protein intake influences such muscle deconditioning requires further investigation. OBJECTIVES To assess the influence of graded dietary protein intakes on daily MyoPS rates and the loss of muscle mass during 3 d of disuse. METHODS Thirty-three healthy young men (aged 22 ± 1 y; BMI = 23 ± 1 kg/m2) initially consumed the same standardized diet for 5 d, providing 1.6 g protein/kg body mass/d. Thereafter, participants underwent a 3-d period of unilateral leg immobilization during which they were randomly assigned to 1 of 3 eucaloric diets containing relatively high, low, or no protein (HIGH: 1.6, LOW: 0.5, NO: 0.15 g protein/kg/d; n = 11 per group). One day prior to immobilization participants ingested 400 mL deuterated water (D2O) with 50-mL doses consumed daily thereafter. Prior to and immediately after immobilization upper leg bilateral MRI scans and vastus lateralis muscle biopsies were performed to measure quadriceps muscle volume and daily MyoPS rates, respectively. RESULTS Quadriceps muscle volume of the control legs remained unchanged throughout the experiment (P > 0.05). Immobilization led to 2.3 ± 0.4%, 2.7 ± 0.2%, and 2.0 ± 0.4% decreases in quadriceps muscle volume (P < 0.05) of the immobilized leg in the HIGH, LOW, and NO groups (P < 0.05), respectively, with no significant differences between groups (P > 0.05). D2O ingestion resulted in comparable plasma free [2H]-alanine enrichments during immobilization (∼2.5 mole percentage excess) across groups (P > 0.05). Daily MyoPS rates during immobilization were 30 ± 2% (HIGH), 26 ± 3% (LOW), and 27 ± 2% (NO) lower in the immobilized compared with the control leg, with no significant differences between groups (P > 0.05). CONCLUSIONS Three days of muscle disuse induces considerable declines in muscle mass and daily MyoPS rates. However, daily protein intake does not modulate any of these muscle deconditioning responses.Clinical trial registry number: NCT03797781.
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Comparison of the acute metabolic effect of different infant formulas and human milk in healthy adults: a randomized trial.
Shahkhalili, Y, Monnard, C, Grathwohl, D, Sauser, J, Beaumont, M, Zufferey, CA, Macé, K
Nutrition & diabetes. 2021;(1):13
Abstract
BACKGROUND/OBJECTIVES Different infant formulas, varying in protein type and quantity, are available for infants who are not breastfed or are partially breastfed. Postprandial insulinemic and glycemic responses to intact vs partially hydrolyzed protein in infant formula are unclear. To compare the effect of different forms (partially hydrolyzed vs non-hydrolyzed) and levels of protein in infant formula compared with a human milk reference subgroup on insulin response in adults. SUBJECTS/METHODS In a randomized, double-blinded, cross-over study, 35 healthy adults consumed 600 ml of three different infant formulas: Intact protein-based formula (INTACT) (1.87 g protein/100 kcal; whey/casein ratio of 70/30; 63 kcal/100 ml), partially hydrolyzed whey-based formula (PHw) (1.96 g protein/100 kcal; 100% whey; 63 kcal/100 ml), a high-protein partially hydrolyzed whey-based formula (HPPHw) (2.79 g protein/100 kcal; 100%whey; 73 kcal/100 ml) and a subgroup also consumed human milk (HM) (n = 11). Lipid and carbohydrate (lactose) contents were similar (5.1-5.5 and 10.5-11.6 g/100 kcal, respectively). Venous blood samples were taken after overnight fasting and at different intervals for 180 min post-drink for insulin, glucose, blood lipids, GLP-1, glucagon, and C-peptide. RESULTS Twenty-nine subjects (eight consuming HM) adhered to the protocol. INTACT and PHw groups had similar postprandial insulinemia and glycaemia (Cmax and iAUC) that were not different from those of the HM subgroup. HPPHw resulted in higher postprandial insulin responses (iAUC) relative to all other groups (p < 0.001, p < 0.001, p = 0.002 for the comparison with INTACT, PHw, HM, respectively). HPPHw resulted in a higher glucose response compared to INTACT and PHw (iAUC: p = 0.003, p = 0.001, respectively), but was not different from HM (p = 0.41). CONCLUSION This study in adults demonstrates similar postprandial insulinemia and glycaemia between INTACT and PHw, close to that of HM, but lower than HPPHw, which had a higher protein content compared to the other test milks. The findings remain to be confirmed in infants. CLINICAL TRIAL REGISTRATION This study is registered at clinicaltrials.gov, identifier NCT04332510.
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Association of normalized protein catabolic rate (nPCR) with the risk of bone fracture in patients undergoing maintenance hemodialysis: The Q-Cohort Study.
Ohnaka, S, Yamada, S, Tsujikawa, H, Arase, H, Taniguchi, M, Tokumoto, M, Tsuruya, K, Nakano, T, Kitazono, T
Clinical nutrition (Edinburgh, Scotland). 2021;(3):997-1004
Abstract
BACKGROUND & AIMS Normalized protein catabolic rate (nPCR) is used as a surrogate for daily dietary protein intake and nutritional status in patients receiving maintenance hemodialysis. It remains uncertain whether the nPCR level is associated with the incidence of bone fracture. METHODS A total of 2869 hemodialysis patients registered in the Q-Cohort Study, a multicenter, prospective, observational study, were followed up for 4 years. The primary outcome was bone fracture at any site. The main exposure was the nPCR level at baseline. Patients were assigned to four groups based on their baseline nPCR levels (G1: <0.85, G2: 0.85≤, <0.95, G3: 0.95≤, <1.05 [reference], G4: ≥1.05 g/kg/day). We examined the relationship between the nPCR levels and the risk for bone fracture using Cox proportional hazards models. RESULTS During the follow-up period, 136 patients experienced bone fracture at any site. In the multivariable analyses, the risk for bone fracture was significantly higher in the lowest (G1) and highest (G4) nPCR groups than the reference (G3) group (hazard ratio [95% confidence intervals]: G1, 1.93 [1.04-3.58]; G2, 1.27 [0.67-2.40]; G3 1.00 (reference); G4, 2.21 [1.25-3.92]). The association remained almost unchanged, even when patients were divided into sex-specific nPCR quartiles, when analysis was limited to patients with a dialysis vintage ≥2 years, assumed to have lost residual kidney function, or when a competing risk model was applied. CONCLUSIONS Our results suggest that both lower and higher nPCR levels are associated with an increased risk for bone fracture in hemodialysis patients.
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Dietary protein and protein substitute requirements in adults with phenylketonuria: A review of the clinical guidelines.
Firman, S, Witard, OC, O'Keeffe, M, Ramachandran, R
Clinical nutrition (Edinburgh, Scotland). 2021;(3):702-709
Abstract
Lifelong dietary treatment is recommended in the management of phenylketonuria (PKU). Accordingly, an increasing adult population require age-specific PKU guidelines on protein requirements to support changing metabolic demands across the lifespan. Given that protein intake for dietary management of PKU is primarily (52-80%) derived from protein substitutes, the prescribing practice of protein substitutes must be underpinned by robust evidence. Whilst dietary guidelines for PKU management is evolving to incorporate adult specific protein recommendations, the scientific evidence underpinning these guidelines is currently limited. Instead, the determination of protein requirements for people with PKU have previously been extrapolated from estimates derived from the general healthy population, based on arguably outdated nitrogen balance methodology. Furthermore, a compensatory factor of 20-40% has been incorporated to account for the reduced uptake and utilisation of the elemental amino acids contained in protein substitutes. However, research informing this compensatory factor has been conducted in younger adults, with the majority of studies in non-PKU individuals. Given extensive evidence that the muscle anabolic response to ingested protein is impaired in older vs. young adults, the validity of current dietary protein recommendations for adults and older adults with PKU has been challenged. This narrative review aims to critically evaluate the existing scientific evidence underpinning current guidelines on protein requirements for adults with PKU, highlighting existing gaps in knowledge and directions for future research. We argue that current guidelines on protein requirements need updating to optimise long-term physical and functional outcomes in older adults with PKU.