-
Current Nutrition Reports Dec 2019The purpose of this review is to provide background on the present literature regarding the utility and effectiveness of protein supplements, including protein source... (Review)
Review
PURPOSE OF REVIEW
The purpose of this review is to provide background on the present literature regarding the utility and effectiveness of protein supplements, including protein source and nutrient timing.
RECENT FINDINGS
In the setting of adequate dietary protein consumption, research suggests some benefit particularly in sport or exercise activities. Protein supplements command a multi-billion-dollar market with prevalent use in sports. Many individuals, including athletes, do not consume optimal dietary protein on a daily basis. High-protein diets are remarkably safe in healthy subjects, especially in the short term. Some objective outcomes are physiologic and may not translate to clinically relevant outcomes. Athletes should, however, consider long-term implications when consuming high quantities of protein in dietary or supplement form.
Topics: Athletes; Athletic Performance; Body Composition; Databases, Factual; Dietary Proteins; Dietary Supplements; Energy Metabolism; Humans; Nutrients; Physical Education and Training; Sports
PubMed: 31713177
DOI: 10.1007/s13668-019-00293-1 -
Journal of Animal Science Apr 1991Exogenous porcine somatotropin (PST) administration stimulates protein deposition and inhibits lipogenesis, resulting in dose-related improvements in growth performance... (Review)
Review
Interrelationships between exogenous porcine somatotropin (PST) administration and dietary protein and energy intake on protein deposition capacity and energy metabolism of pigs.
Exogenous porcine somatotropin (PST) administration stimulates protein deposition and inhibits lipogenesis, resulting in dose-related improvements in growth performance and reduction of carcass fat content. However, the associated impacts of this technology on dietary nutrient requirements and energy partitioning between maintenance, protein, and fat remain unclear. Studies with pigs between 25 and 60 kg body weight indicate that, because of unknown improvements in amino acid utilization and(or) in the energy available for protein synthesis, only marginal increases in dietary protein percentage are required to support 20 to 25% improvements in protein deposition induced by PST administration. In contrast, an increased dietary protein concentration is required to support maximal protein deposition in pigs 60 to 100 kg. Exogenous PST administration increased the maintenance energy requirement and altered the relationship between energy intake and protein deposition, although the magnitude of these changes and the consequent effects on expression of dietary protein (amino acid) requirements was influenced by gender. Albeit limited, information suggests that PST alters nutrient demand at the tissue level. Information of this type will form the basis for rational decisions concerning the method for expression of dietary nutrient requirements (% vs g/d) for PST-treated pigs. Further quantitative information is required on the effects of PST dosage on the relationship of protein deposition to energy intake and on any underlying changes in amino acid utilization and metabolism.
Topics: Animals; Dietary Proteins; Energy Intake; Energy Metabolism; Growth Hormone; Swine
PubMed: 2071517
DOI: 10.2527/1991.6941522x -
Journal of Nutritional Science and... Oct 1990August 28 and 29, 1989, a workshop entitled "Dietary protein as a regulator of lipid metabolism" was held in Fukuoka. This workshop highlighted the progress that has... (Comparative Study)
Comparative Study Review
August 28 and 29, 1989, a workshop entitled "Dietary protein as a regulator of lipid metabolism" was held in Fukuoka. This workshop highlighted the progress that has been made since 1909, the year that Ignatowski put forward that animal proteins in the diet can induce atherosclerosis in rabbits. It is now clear that humans respond to dietary soybean protein versus animal proteins, such as casein, with a decrease of serum cholesterol concentrations. However, the response in humans is not as pronounced as it is in various animal models. The mechanism by which the type of dietary protein affects serum cholesterol concentrations is still a matter of debate but various elegant concepts have been launched. These concepts have contributed significantly to our current understanding of the regulation of cholesterol metabolism. Future work will concentrate on further unravelling the mechanisms involved, with special reference to proteins other than those used generally, that is soybean protein and casein.
Topics: Animals; Caseins; Cholesterol; Dietary Proteins; Humans; Lipid Metabolism; Plant Proteins, Dietary; Soybean Proteins
PubMed: 2130154
DOI: 10.3177/jnsv.36.supplementii_s185 -
The American Journal of Clinical... Nov 2005
Topics: Acid-Base Equilibrium; Bone Density; Bone Development; Bone and Bones; Dietary Proteins; Humans; Insulin-Like Growth Factor I
PubMed: 16280420
DOI: 10.1093/ajcn/82.5.921 -
Scientific Reports Nov 2019The aim of the study was to evaluate the ruminal function and microbial community of lamb under different nutrient levels. Sixty-four lambs with similarity body weight...
The aim of the study was to evaluate the ruminal function and microbial community of lamb under different nutrient levels. Sixty-four lambs with similarity body weight were randomly assigned to four groups after weaning off ewe's milk on the 17th day (6.2 ± 0.2 kg). The lambs of the control group (CON) were fed a basal diet, and the other three groups were subjected to a diet of decreased protein (PR), digestible energy (ER) or both of them at 20% (BR) of basal diet. The decrease of dietary protein or energy level decreased the average daily gain, ruminal weight and mucosal thickness of lambs (P < 0.05). The total volatile fatty acid (TVFA), acetate and propionate concentration of the CON group were significantly higher than that of the other three groups. The dietary protein and energy level affected the microbial diversity, and low energy level increased the relative abundance of phyla of Fibrobacteres, whereas at the genus level, increased the relative abundance of Butyrivibrio and Prevotellaceae. Under different dietary energy and protein levels, 14 genera exhibited significant correlation with ruminal fermentation. These findings supplied new perspective for the understanding of the dietary effect on ruminal microbial community interactions and are of great significance for establishing the optimal nutrient supply strategy for lambs.
Topics: Animals; Dietary Proteins; Energy Intake; Fermentation; Gastrointestinal Microbiome; Rumen; Sheep
PubMed: 31719633
DOI: 10.1038/s41598-019-53279-y -
Nutrients Aug 2015Declines in skeletal muscle mass and strength are major contributors to increased mortality, morbidity and reduced quality of life in older people. Recommended Dietary... (Review)
Review
Declines in skeletal muscle mass and strength are major contributors to increased mortality, morbidity and reduced quality of life in older people. Recommended Dietary Allowances/Intakes have failed to adequately consider the protein requirements of the elderly with respect to function. The aim of this paper was to review definitions of optimal protein status and the evidence base for optimal dietary protein. Current recommended protein intakes for older people do not account for the compensatory loss of muscle mass that occurs on lower protein intakes. Older people have lower rates of protein synthesis and whole-body proteolysis in response to an anabolic stimulus (food or resistance exercise). Recommendations for the level of adequate dietary intake of protein for older people should be informed by evidence derived from functional outcomes. Randomized controlled trials report a clear benefit of increased dietary protein on lean mass gain and leg strength, particularly when combined with resistance exercise. There is good consistent evidence (level III-2 to IV) that consumption of 1.0 to 1.3 g/kg/day dietary protein combined with twice-weekly progressive resistance exercise reduces age-related muscle mass loss. Older people appear to require 1.0 to 1.3 g/kg/day dietary protein to optimize physical function, particularly whilst undertaking resistance exercise recommendations.
Topics: Accidental Falls; Aged; Aging; Body Composition; Bone and Bones; Dietary Proteins; Elder Nutritional Physiological Phenomena; Energy Intake; Energy Metabolism; Fractures, Bone; Humans; Motor Activity; Muscle Strength; Muscle, Skeletal; Randomized Controlled Trials as Topic; Recommended Dietary Allowances
PubMed: 26287239
DOI: 10.3390/nu7085311 -
The American Journal of Clinical... Aug 2020Protein ingestion increases skeletal muscle protein synthesis rates during recovery from endurance exercise. (Randomized Controlled Trial)
Randomized Controlled Trial
BACKGROUND
Protein ingestion increases skeletal muscle protein synthesis rates during recovery from endurance exercise.
OBJECTIVES
We aimed to determine the effect of graded doses of dietary protein co-ingested with carbohydrate on whole-body protein metabolism, and skeletal muscle myofibrillar (MyoPS) and mitochondrial (MitoPS) protein synthesis rates during recovery from endurance exercise.
METHODS
In a randomized, double-blind, parallel-group design, 48 healthy, young, endurance-trained men (mean ± SEM age: 27 ± 1 y) received a primed continuous infusion of l-[ring-2H5]-phenylalanine, l-[ring-3,5-2H2]-tyrosine, and l-[1-13C]-leucine and ingested 45 g carbohydrate with either 0 (0 g PRO), 15 (15 g PRO), 30 (30 g PRO), or 45 (45 g PRO) g intrinsically l-[1-13C]-phenylalanine and l-[1-13C]-leucine labeled milk protein after endurance exercise. Blood and muscle biopsy samples were collected over 360 min of postexercise recovery to assess whole-body protein metabolism and both MyoPS and MitoPS rates.
RESULTS
Protein intake resulted in ∼70%-74% of the ingested protein-derived phenylalanine appearing in the circulation. Whole-body net protein balance increased dose-dependently after ingestion of 0, 15, 30, or 45 g protein (mean ± SEM: -0.31± 0.16, 5.08 ± 0.21, 10.04 ± 0.30, and 13.49 ± 0.55 μmol phenylalanine · kg-1 · h-1, respectively; P < 0.001). 30 g PRO stimulated a ∼46% increase in MyoPS rates (%/h) compared with 0 g PRO and was sufficient to maximize MyoPS rates after endurance exercise. MitoPS rates were not increased after protein ingestion; however, incorporation of dietary protein-derived l-[1-13C]-phenylalanine into de novo mitochondrial protein increased dose-dependently after ingestion of 15, 30, and 45 g protein at 360 min postexercise (0.018 ± 0.002, 0.034 ± 0.002, and 0.046 ± 0.003 mole percentage excess, respectively; P < 0.001).
CONCLUSIONS
Protein ingested after endurance exercise is efficiently digested and absorbed into the circulation. Whole-body net protein balance and dietary protein-derived amino acid incorporation into mitochondrial protein respond to increasing protein intake in a dose-dependent manner. Ingestion of 30 g protein is sufficient to maximize MyoPS rates during recovery from a single bout of endurance exercise.This trial was registered at trialregister.nl as NTR5111.
Topics: Adult; Amino Acids; Dietary Proteins; Double-Blind Method; Endurance Training; Exercise; Humans; Male; Muscle Proteins; Muscle, Skeletal
PubMed: 32359142
DOI: 10.1093/ajcn/nqaa073 -
Bone 1992
Review
Topics: Adult; Bone Diseases, Metabolic; Child; Dietary Proteins; Humans; Nutritional Requirements; Protein Deficiency
PubMed: 1389576
DOI: 10.1016/8756-3282(92)90081-7 -
European Journal of Clinical Nutrition Apr 1999Ingested protein is made available to the body following digestion and absorption as amino acids and contributes to the body's demand for amino acids for protein... (Review)
Review
Ingested protein is made available to the body following digestion and absorption as amino acids and contributes to the body's demand for amino acids for protein synthesis and other metabolic pathways. As the pattern of amino acids required for metabolism is substantially different from that ingested, extensive metabolic interchange serves to improve the match. As a matter of course oxidation of amino acids contributes to satisfying the energy needs of the body. Amino acids in excess of immediate requirements follow degradative pathways and if the capacity of these pathways is exceeded adverse consequences ensue. In pathological states, such as inborn errors of metabolism, there is an obvious constraint on metabolic flow with serious sequelae. Pathways may be constrained to a lesser extent due to genetic polymorphisms, metabolic programming, limitation of cofactors or lack of associated substrates. Any of these can result in metabolic derangements, which do not manifest as overt disease, but limit normal function. There is the need to determine the dose response to increases in dietary protein and amino acid availability, using critical metabolic intermediates as outcome indices in order to clarify the upper limit of intake with which the body can cope under a range of physiological and pathological states.
Topics: Adaptation, Physiological; Adult; Amino Acids; Circadian Rhythm; Dietary Proteins; Energy Intake; Energy Metabolism; Female; Humans; Infant; Infant, Newborn; Intestinal Absorption; Nitrogen; Nutritional Requirements; Oxidation-Reduction; Polymorphism, Genetic; Pregnancy
PubMed: 10365980
DOI: 10.1038/sj.ejcn.1600743 -
The Physician and Sportsmedicine Jun 2009Dietary protein is required to promote growth, repair damaged cells and tissue, synthesize hormones, and for a variety of metabolic activities. There are multiple... (Review)
Review
Dietary protein is required to promote growth, repair damaged cells and tissue, synthesize hormones, and for a variety of metabolic activities. There are multiple sources of proteins available; however, animal sources of protein contain all essential amino acids and are considered complete sources of protein, whereas plant proteins lack some of the essential amino acids and are therefore classified as incomplete. There is a significant body of evidence to indicate that individuals who are engaged in intense training require more dietary protein than sedentary counterparts (ie, 1.4-2 g/kg/day). For most individuals, this level of protein intake can be obtained from a regular and varied diet. However, recent evidence indicates that ingesting protein and/or amino acids prior to, during, and/or following exercise can enhance recovery, immune function, and growth and maintenance of lean body mass. Consequently, protein and amino acid supplements can serve as a convenient way to ensure a timely and/or adequate intake for athletes. Finally, adequate intake and appropriate timing of protein ingestion has been shown to be beneficial in multiple exercise modes, including endurance, anaerobic, and strength exercise.
Topics: Amino Acids; Body Composition; Dietary Proteins; Exercise; Humans; Nutritional Requirements; Physical Endurance; Sports
PubMed: 20048505
DOI: 10.3810/psm.2009.06.1705