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Nutrition Reviews Dec 2017Consumption of sufficient dietary protein is fundamental to muscle mass maintenance and overall health. Conventional animal-based protein sources such as meat (ie, beef,... (Review)
Review
Consumption of sufficient dietary protein is fundamental to muscle mass maintenance and overall health. Conventional animal-based protein sources such as meat (ie, beef, pork, lamb), poultry, fish, eggs, and dairy are generally considered high-quality sources of dietary protein because they meet all of the indispensable amino-acid requirements for humans and are highly digestible. However, the production of sufficient amounts of conventional animal-based protein to meet future global food demands represents a challenge. Edible insects have recently been proposed as an alternative source of dietary protein that may be produced on a more viable and sustainable commercial scale and, as such, may contribute to ensuring global food security. This review evaluates the protein content, amino-acid composition, and digestibility of edible insects and considers their proposed quality and potential as an alternative protein source for human consumption.
Topics: Amino Acids; Amino Acids, Essential; Animals; Diet; Dietary Proteins; Food Supply; Humans; Insecta
PubMed: 29202184
DOI: 10.1093/nutrit/nux057 -
Sports Medicine (Auckland, N.Z.) Sep 1989The dietary protein requirement of physically active individuals has received considerable scrutiny in recent years. Because the current United States Recommended Daily... (Review)
Review
The dietary protein requirement of physically active individuals has received considerable scrutiny in recent years. Because the current United States Recommended Daily Allowance (USRDA) for protein (0.8 g/kg/day) already contains a safety margin (0.35 g/kg/day) to assure adequate protein intake, no increment in the USRDA was thought necessary to meet the demands of physical activity. Recently, collective evidence from research techniques utilising nitrogen balance, labelled amino acid isotopes, urea production and 3-methylhistidine excretion indicates that exercise (endurance and weightlifting) can significantly alter protein metabolism and that the dietary protein needs of physically active individuals may exceed the current USRDA. During endurance exercise, protein synthesis is depressed and protein degradation increases. Thus, amino acids become available for oxidation in energy-yielding processes. Amino acid catabolism has been estimated to contribute between 5 and 15% of the energy required during endurance exercise. Definitive conclusions regarding the changes that occur in protein synthesis and protein degradation during weightlifting exercise must await further research. The net contribution of amino acids to the energy required during weightlifting exercise is unknown but, due to the anaerobic nature of the event, it is most likely less than during endurance exercise. However, following both endurance and weightlifting exercise, protein synthesis increases. Based on current research, it is not yet possible to make recommendations for the daily protein needs of exercising individuals. It does appear that physically active individuals require more dietary protein per kilogram of bodyweight than sedentary individuals. However, when protein intake is expressed as a percentage of daily energy intake, physically active and sedentary individuals have similar requirements (approximately 12 to 15% of total energy as protein). Therefore, to cover the protein requirements of both physically active individuals and sedentary individuals it is suggested that future protein allowances be based on a percentage of the daily energy requirements. Protein consumption in excess of the current USRDA may minimise changes in body nitrogen stores, particularly during the first few weeks of training. However, further research is needed before a definitive conclusion can be made regarding protein ingestion and athletic performance.
Topics: Adult; Body Composition; Dietary Proteins; Exercise; Humans; Nutritional Requirements; Physical Endurance; Sports
PubMed: 2690267
DOI: 10.2165/00007256-198908030-00003 -
Molecular and Cellular Endocrinology Jul 2015Dietary protein is required for optimal skeletal growth and maturation. Although Recommended Dietary Allowances (RDAs) exist for global dietary protein intake, the level... (Review)
Review
Dietary protein is required for optimal skeletal growth and maturation. Although Recommended Dietary Allowances (RDAs) exist for global dietary protein intake, the level and sources of dietary protein that are optimal for skeletal health over the life continuum have not been established. This is partly due to the difficulty in quantifying the effects of variable levels of a nutrient's intake over a lifetime as well as the complex nature of the relationships between dietary protein and calcium economy. Areas of current uncertainty include the precise source and amount of dietary protein required for optimal skeletal accretion and maintenance of skeletal mass, as well as the site-specific effects of dietary protein. The cellular and molecular mechanisms that underpin the actions of dietary protein on mineral metabolism and skeletal homeostasis remain unclear. This review attempts to summarize recent data bearing on these questions.
Topics: Amino Acids; Bone Density; Bone Development; Bone and Bones; Dietary Proteins; Humans
PubMed: 25843057
DOI: 10.1016/j.mce.2015.03.024 -
Age and Ageing Jul 2016Nutrition has profound effects on ageing and lifespan. Caloric restriction is the major nutritional intervention that historically has been shown to influence lifespan... (Review)
Review
Nutrition has profound effects on ageing and lifespan. Caloric restriction is the major nutritional intervention that historically has been shown to influence lifespan and/or healthspan in many animal models. Studies have suggested that a reduction in protein intake can also increase lifespan, albeit not as dramatically as caloric restriction. More recent research based on nutritional geometry has attempted to define the effects of nutrition on ageing over a broad landscape of dietary macronutrients and energy content. Such studies in insects and mice indicate that animals with ad libitum access to low-protein, high-carbohydrate diets have longest lifespans. Remarkably, the optimum content and ratio of dietary protein to carbohydrates for ageing in experimental animals are almost identical to those in the traditional diets of the long-lived people on the island of Okinawa.
Topics: Age Factors; Aging; Animals; Caloric Restriction; Diet, Protein-Restricted; Dietary Carbohydrates; Dietary Proteins; Humans; Japan; Life Expectancy; Models, Animal; Nutritional Status
PubMed: 27130207
DOI: 10.1093/ageing/afw069 -
The Journal of Nutrition Jun 1998Too little protein is always harmful for the skeleton. Increasing dietary protein increases endogenous calcium excretion. The ability to adapt depends upon the adequacy... (Review)
Review
Too little protein is always harmful for the skeleton. Increasing dietary protein increases endogenous calcium excretion. The ability to adapt depends upon the adequacy of an individual's calcium intake. At a population level, the effect of protein is often minimized because calcium intake rises with increasing protein intake. A dietary calcium-to-protein ratio >/=20:1 (mg:g) probably provides adequate protection for the skeleton. Excess protein will not harm the skeleton if the calcium intake is adequate.
Topics: Bone and Bones; Calcium; Diet; Dietary Proteins; Humans
PubMed: 9614170
DOI: 10.1093/jn/128.6.1054 -
Future Microbiology Oct 2013The breakdown of proteins and peptides by colonic microorganisms yields a great diversity of end products, including short-chain fatty acids, ammonia, amines, phenols,... (Review)
Review
The breakdown of proteins and peptides by colonic microorganisms yields a great diversity of end products, including short-chain fatty acids, ammonia, amines, phenols, indoles, thiols, CO2, H2 and H2S, many of which have toxic properties. An increase of the dietary protein load in healthy individuals results in enhanced generation of these toxins, many of which are rapidly cleared by the kidneys. In this regard, the impact upon the colonic microbiota of controlled changes in the dietary protein has not been examined in chronic kidney disease patients. This review focuses on the impact of dietary proteins on the intestinal microbiota and its possible consequences for chronic kidney disease patients.
Topics: Animals; Bacteria; Dietary Proteins; Gastrointestinal Tract; Humans; Microbiota; Renal Insufficiency, Chronic
PubMed: 24059921
DOI: 10.2217/fmb.13.103 -
Nutrition Reviews Feb 1968
Review
Topics: Acute Kidney Injury; Dietary Proteins; Humans; Renal Dialysis; Water-Electrolyte Balance
PubMed: 4867314
DOI: 10.1111/j.1753-4887.1968.tb00854.x -
Osteoporosis International : a Journal... Sep 2018A summary of systematic reviews and meta-analyses addressing the benefits and risks of dietary protein intakes for bone health in adults suggests that dietary protein... (Review)
Review
Benefits and safety of dietary protein for bone health-an expert consensus paper endorsed by the European Society for Clinical and Economical Aspects of Osteopororosis, Osteoarthritis, and Musculoskeletal Diseases and by the International Osteoporosis Foundation.
A summary of systematic reviews and meta-analyses addressing the benefits and risks of dietary protein intakes for bone health in adults suggests that dietary protein levels even above the current RDA may be beneficial in reducing bone loss and hip fracture risk, provided calcium intakes are adequate. Several systematic reviews and meta-analyses have addressed the benefits and risks of dietary protein intakes for bone health in adults. This narrative review of the literature summarizes and synthesizes recent systematic reviews and meta-analyses and highlights key messages. Adequate supplies of dietary protein are required for optimal bone growth and maintenance of healthy bone. Variation in protein intakes within the "normal" range accounts for 2-4% of BMD variance in adults. In older people with osteoporosis, higher protein intake (≥ 0.8-g/kg body weight/day, i.e., above the current RDA) is associated with higher BMD, a slower rate of bone loss, and reduced risk of hip fracture, provided that dietary calcium intakes are adequate. Intervention with dietary protein supplements attenuate age-related BMD decrease and reduce bone turnover marker levels, together with an increase in IGF-I and a decrease in PTH. There is no evidence that diet-derived acid load is deleterious for bone health. Thus, insufficient dietary protein intakes may be a more severe problem than protein excess in the elderly. Long-term, well-controlled randomized trials are required to further assess the influence of dietary protein intakes on fracture risk.
Topics: Acid-Base Equilibrium; Bone Density; Bone Remodeling; Calcium, Dietary; Dietary Proteins; Humans; Osteoporosis; Osteoporotic Fractures; Risk Assessment
PubMed: 29740667
DOI: 10.1007/s00198-018-4534-5 -
Current Opinion in Clinical Nutrition... Jan 2007Whereas diet and exercise have been shown to influence whole-body protein utilization, little is known about the impact of these factors on skeletal-muscle protein... (Review)
Review
PURPOSE OF REVIEW
Whereas diet and exercise have been shown to influence whole-body protein utilization, little is known about the impact of these factors on skeletal-muscle protein turnover. We highlight the role of dietary protein in modulating skeletal-muscle protein turnover in response to endurance exercise. Effects of endurance exercise on skeletal-muscle protein metabolism are presented and the influence of habitual protein intake on exercise-related protein responses is discussed.
RECENT FINDINGS
Skeletal-muscle protein turnover increases in response to endurance exercise training and following a single endurance exercise bout. Nutritional supplementation postexercise favorably affects skeletal-muscle protein synthesis and demonstrates amino acid availability as pivotal to the skeletal-muscle synthetic response following exercise. The level of habitual protein intake influences postexercise skeletal-muscle protein turnover.
SUMMARY
Dietary protein and exercise are powerful stimuli affecting protein turnover. Since variation in habitual protein intake influences skeletal-muscle protein turnover postexercise, investigations are needed to determine what role protein intake has in regulating skeletal-muscle protein metabolism. Long-term, well controlled diet and exercise intervention studies are essential for clarification of the relation between protein intake, endurance exercise, and skeletal-muscle protein turnover. Studies designed to characterize this relationship should be attentive to habitual macronutrient and energy intakes.
Topics: Biological Availability; Dietary Proteins; Humans; Muscle Proteins; Muscle, Skeletal; Physical Endurance
PubMed: 17143053
DOI: 10.1097/MCO.0b013e3280115e3b -
Biochimica Et Biophysica Acta Mar 2010Lipotoxicity is a metabolic abnormality frequently observed during the development of obesity and is the main cause of several changes in the metabolic observed during... (Review)
Review
Lipotoxicity is a metabolic abnormality frequently observed during the development of obesity and is the main cause of several changes in the metabolic observed during metabolic syndrome. Consistent consumption of diets high in saturated fat or simple carbohydrates combined with low physical activity are the main causes of obesity and its comorbidities. However, the contribution of dietary protein and, in particular, the contribution due to the type of dietary protein, to the process of obesity and its metabolic consequences are less well-understood. In this review, we showed that the type of dietary protein has a significant contribution to the process of lipotoxicity through the modulation of insulin secretion and the regulation of adipocyte metabolic function. Consumption of soy protein stimulates insulin secretion to a lower extent than casein despite the fact that both are high-quality proteins. The amino acid profiles of soy protein and its isoflavones are responsible for the reduced insulin secretion. Also, soy protein increases insulin sensitivity, whereas casein has the opposite effect. Consequently, soy protein reduces SREBP-1 expression in the liver leading to low accumulation of hepatic triglycerides, despite the consumption of a high-fat diet. Furthermore, soy protein reduces adipocyte hypertrophy, hyperleptinemia, and free fatty acid concentration. Thus, the influx of FA into the liver decreases, and hepatic oxidation of FA increases. These metabolic changes result in a decrease in lipid depots and ceramide which reduce hepatic lipotoxicity, whereas casein produces the opposite effect. This study emphasizes that the type of dietary protein has an important effect on lipotoxicity.
Topics: Adipocytes; Animals; Dietary Proteins; Humans; Insulin; Lipid Metabolism; Lipogenesis; Models, Biological; Obesity
PubMed: 19800415
DOI: 10.1016/j.bbalip.2009.09.007