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Dietary Protein, Kidney Function and Mortality: Review of the Evidence from Epidemiological Studies.Nutrients Jan 2019The World Health Organization recommends a minimum requirement of 0.8 g/day protein/kg ideal weight. Low protein diets are used against kidney failure progression.... (Review)
Review
The World Health Organization recommends a minimum requirement of 0.8 g/day protein/kg ideal weight. Low protein diets are used against kidney failure progression. Efficacy and safety of these diets are uncertain. This paper reviews epidemiological studies about associations of protein intake with kidney function decline and mortality. Three studies investigated these associations; two reported data on mortality. Protein intake averaged >60 g/day and 1.2 g/day/kg ideal weight. An association of baseline protein intake with long-term kidney function decline was absent in the general population and/or persons with normal kidney function but was significantly positive in persons with below-normal kidney function. Independent of kidney function and other confounders, a J-curve relationship was found between baseline protein intake and mortality due to ≈35% mortality excess for non-cardiovascular disease in the lowest quintile of protein intake, a quintile where protein intake averaged <0.8 g/day/kg ideal weight. Altogether, epidemiological evidence suggests that, in patients with reduced kidney function, protein intakes of ≈0.8 g/d/kg ideal weight could limit kidney function decline without adding non-renal risks. Long-term lower protein intake could increase mortality. In most patients, an intake of ≈0.8 g/day/kg would represent a substantial reduction of habitual intake considering that average intake is largely higher.
Topics: Cause of Death; Diet, Protein-Restricted; Dietary Proteins; Humans; Kidney; Nutritional Requirements; Recommended Dietary Allowances; Renal Insufficiency
PubMed: 30669401
DOI: 10.3390/nu11010196 -
Nutrients Jul 2018Muscle mass, strength, and physical function are known to decline with age. This is associated with the development of geriatric syndromes including sarcopenia and... (Review)
Review
Muscle mass, strength, and physical function are known to decline with age. This is associated with the development of geriatric syndromes including sarcopenia and frailty. Dietary protein is essential for skeletal muscle function. Resistance exercise appears to be the most beneficial form of physical activity for preserving skeletal muscle and a synergistic effect has been noted when this is combined with dietary protein. However, older adults have shown evidence of anabolic resistance, where greater amounts of protein are required to stimulate muscle protein synthesis, and response is variable. Thus, the recommended daily amount of protein is greater for older people. The aetiologies and mechanisms responsible for anabolic resistance are not fully understood. The gut microbiota is implicated in many of the postulated mechanisms for anabolic resistance, either directly or indirectly. The gut microbiota change with age, and are influenced by dietary protein. Research also implies a role for the gut microbiome in skeletal muscle function. This leads to the hypothesis that the gut microbiome might modulate individual response to protein in the diet. We summarise the existing evidence for the role of the gut microbiota in anabolic resistance and skeletal muscle in aging people, and introduce the metabolome as a tool to probe this relationship in the future.
Topics: Aging; Diet; Dietary Proteins; Feeding Behavior; Female; Frailty; Gastrointestinal Microbiome; Humans; Male; Muscle Proteins; Muscle, Skeletal; Nutritional Requirements; Nutritional Status; Resistance Training; Sarcopenia
PubMed: 30036990
DOI: 10.3390/nu10070929 -
The Journal of Nutrition Jan 2015Many misconceptions surround the role of dietary protein in the management of diabetes. Although dietary recommendations for managing diabetes have changed greatly over... (Review)
Review
Many misconceptions surround the role of dietary protein in the management of diabetes. Although dietary recommendations for managing diabetes have changed greatly over the centuries, recommended protein intake has remained relatively constant. Currently, recommendations for protein intake are based on individual assessment and the consideration of other health issues and implications, such as the extent of glycemic control, the presence of kidney disease, overweight and obesity, and the age of the patient. Two common misconceptions about dietary protein in diabetes management are that a certain amount of the protein consumed is converted into blood glucose and that consuming too much protein can lead to diabetic kidney disease. These misconceptions have been disproven. For many people with type 2 diabetes, aiming for 20-30% of total energy intake as protein is the goal. Exceptions may be for those individuals with impaired renal function. A protein intake of this amount can be beneficial by improving glycemic control, aiding in satiety and preservation of lean body mass during weight loss in those with both diabetes and prediabetes, and providing for the increased protein requirements of the older adult. Health care providers should discuss the role of dietary protein with their patients, reinforce sources of protein in the diet, and use simple but effective teaching tools, such as the plate method, to convey important nutrition messages. In addition, health care providers should recognize that persons with diabetes are attempting to manage many other aspects of their diabetes, including blood glucose monitoring, physical activity, taking of medication, risk reduction, and problem solving.
Topics: Aged; Aging; Blood Glucose; Body Weight; Diabetes Mellitus, Type 2; Diabetic Nephropathies; Diet, Diabetic; Dietary Proteins; Energy Intake; Exercise; Humans; Kidney; Nutrition Policy; Patient Education as Topic; Prediabetic State
PubMed: 25527675
DOI: 10.3945/jn.114.194878 -
Journal of Cachexia, Sarcopenia and... Jun 2017The dietary protein role in different clinical nutritional conditions and some physio-pathological perspectives is a current and hot topic to discuss. Recent Proceedings...
The dietary protein role in different clinical nutritional conditions and some physio-pathological perspectives is a current and hot topic to discuss. Recent Proceedings of the Protein Summit 2, joining more than 60 nutrition scientists, health experts, and nutrition educators, suggest to increase plant but, in particular, animal protein intake because richer in leucine and consequently more effective to influence anabolic protein metabolism. The Panel conclusions are in apparent contradiction with the nutritional ecology statements, which strongly sustain the reduction of animal origin foods in the human diet and are currently concerned about the excessive, mainly animal protein intake in western and westernized Countries. In conclusion, it is time to carefully evaluate protein and aminoacid intake accurately considering quality, digestibility, daily distribution and individual characteristics.
Topics: Animals; Body Weight Maintenance; Diet; Dietary Proteins; Energy Metabolism; Humans; Nutrition Policy; Nutritional Physiological Phenomena; Nutritional Status
PubMed: 28444858
DOI: 10.1002/jcsm.12176 -
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 -
The American Journal of Clinical... Jul 2021High-protein diets (e.g., Paleo, Atkins, South Beach, ketogenic) have gained popularity as a means to promote weight loss and avoid excess carbohydrate consumption. Yet...
BACKGROUND
High-protein diets (e.g., Paleo, Atkins, South Beach, ketogenic) have gained popularity as a means to promote weight loss and avoid excess carbohydrate consumption. Yet in chronic kidney disease (CKD) patients, evidence suggests low dietary protein intake (DPI) leads to attenuation of kidney function decline, although concerns remain for risk of protein-energy wasting.
OBJECTIVES
To examine associations of DPI with mortality in a nationally representative cohort of US adults, stratified by kidney function.
METHODS
We examined the association between daily DPI scaled to actual body weight (ABW), ascertained by 24-h dietary recall, with all-cause mortality among 27,604 continuous NHANES adult participants (1999-2010), stratified according to impaired versus normal kidney function (estimated glomerular filtration rates <60 compared with ≥60 ml/min/1.72 m2, respectively), using multivariable Cox models. We also examined the relation between high biological value (HBV) protein consumption with mortality.
RESULTS
In participants with impaired kidney function, a high DPI of ≥1.4 g/kg ABW/day was associated with higher mortality, while lower DPI levels were not associated with mortality (reference, 0.6 to <1.0 g/kg ABW/day): the adjusted HRs (aHRs) were 1.09 (95% CI: 0.90, 1.32), 1.03 (95% CI: 0.82, 1.29), and 1.37 (95% CI: 1.02, 1.85) for DPI <0.6, 1.0 to <1.4, and ≥1.4 g/kg ABW/day, respectively. Yet in participants with normal kidney function, a low DPI of <0.6 g/kg ABW/day was associated with higher mortality, whereas higher DPI levels were not associated with death: the aHRs were 1.18 (95% CI: 1.04, 1.34), 0.92 (95% CI: 0.81, 1.04), and 0.99 (95% CI: 0.85, 1.16) for DPI <0.6, 1.0 to <1.4, and ≥1.4 g/kg ABW/day, respectively. The highest 2 tertiles of HBV consumption were associated with higher mortality in participants with impaired kidney function.
CONCLUSIONS
Among participants with impaired kidney function, a higher DPI and greater HBV consumption were associated with higher mortality, whereas a lower DPI was associated with higher mortality in those with normal kidney function. Further studies are needed to elucidate the specific pathways between higher DPI and mortality in CKD.
Topics: Body Weight; Cohort Studies; Diet Records; Dietary Proteins; Exercise; Glomerular Filtration Rate; Humans; Kidney; Kidney Function Tests; Mortality; Risk Factors; United States
PubMed: 33742197
DOI: 10.1093/ajcn/nqab011 -
Experimental & Molecular Medicine Sep 2022There is a general consensus that a dietary protein intake of 0.8 g protein/kg/day will prevent symptoms of protein deficiency in young, healthy individuals. However,... (Review)
Review
There is a general consensus that a dietary protein intake of 0.8 g protein/kg/day will prevent symptoms of protein deficiency in young, healthy individuals. However, individuals in many physiological circumstances may benefit from higher rates of dietary protein intake. Stable isotope tracer methodology enables a variety of approaches to assessing the optimal dietary protein intake in humans. In this paper, we present an overview of a variety of tracer methods, with a discussion of necessary assumptions, as well as the clinical circumstances in which different methods may be preferable. Although we discuss the nontracer method of nitrogen balance, which has historically been used to estimate dietary protein requirements, this paper primarily focuses on tracer methods for estimating dietary protein and essential amino acid requirements under different physiological conditions. We will explain the following approaches: isotopic measurement of urea production; the arterial-venous tracer balance method; measurement of the fractional synthetic and breakdown rates of muscle protein; the indicator and the direct amino acid oxidation methods; and different approaches to measuring whole-body protein synthesis and breakdown. The advantages and limitations of each method are discussed in the context of the optimal approaches for use under different circumstances.
Topics: Amino Acids; Amino Acids, Essential; Dietary Proteins; GTP-Binding Proteins; Humans; Isotopes; Muscle Proteins; Nitrogen; Urea
PubMed: 36075948
DOI: 10.1038/s12276-022-00817-w -
Current Opinion in Lipidology Feb 2011Both dietary calcium and vitamin D are undoubtedly beneficial to skeletal health. In contrast, despite intense investigation, the impact of dietary protein on calcium... (Review)
Review
PURPOSE OF REVIEW
Both dietary calcium and vitamin D are undoubtedly beneficial to skeletal health. In contrast, despite intense investigation, the impact of dietary protein on calcium metabolism and bone balance remains controversial. A widely held view is that high intakes of animal protein result in increased bone resorption, reduced bone mineral density, and increased fractures because of its ability to generate a high fixed metabolic acid load. The purpose of this review is to present the recent or most important epidemiological and clinical trials in humans that evaluated dietary protein's impact on skeletal health.
RECENT FINDINGS
Many epidemiological studies have found a significant positive relationship between protein intake and bone mass or density. Similarly, isotopic studies in humans have also demonstrated greater calcium retention and absorption by individuals consuming high-protein diets, particularly when the calcium content of the diet was limiting. High-protein intake may positively impact bone health by several mechanisms, including calcium absorption, stimulation of the secretion of insulin-like growth factor-1, and enhancement of lean body mass. The concept that an increase in dietary protein induces a large enough shift in systemic pH to increase osteoclastic bone resorption seems untenable.
SUMMARY
Recent epidemiological, isotopic and meta-analysis studies suggest that dietary protein works synergistically with calcium to improve calcium retention and bone metabolism. The recommendation to intentionally restrict dietary protein to improve bone health is unwarranted, and potentially even dangerous to those individuals who consume inadequate protein.
Topics: Bone and Bones; Calcium; Dietary Proteins; Humans
PubMed: 21102327
DOI: 10.1097/MOL.0b013e3283419441 -
Experimental Biology and Medicine... Mar 2018Maternal nutrition during gestation, especially dietary protein intake, is a key determinant in embryonic survival, growth, and development. Low maternal dietary protein... (Review)
Review
Maternal nutrition during gestation, especially dietary protein intake, is a key determinant in embryonic survival, growth, and development. Low maternal dietary protein intake can cause embryonic losses, intra-uterine growth restriction, and reduced postnatal growth due to a deficiency in specific amino acids that are important for cell metabolism and function. Of note, high maternal dietary protein intake can also result in intra-uterine growth restriction and embryonic death, due to amino acid excesses, as well as the toxicity of ammonia, homocysteine, and HS that are generated from amino acid catabolism. Maternal protein nutrition has a pronounced impact on fetal programming and alters the expression of genes in the fetal genome. As a precursor to the synthesis of molecules (e.g. nitric oxide, polyamines, and creatine) with cell signaling and metabolic functions, L-arginine (Arg) is essential during pregnancy for growth and development of the conceptus. With inadequate maternal dietary protein intake, Arg and other important amino acids are deficient in mother and fetus. Dietary supplementation of Arg during gestation has been effective in improving embryonic survival and development of the conceptus in many species, including humans, pigs, sheep, mice, and rats. Both the balance among amino acids and their quantity are critical for healthy pregnancies and offspring. Impact statement This review aims at: highlighting adverse effects of elevated levels of ammonia in mother or fetus on embryonic/fetal survival, growth, and development; helping nutritionists and practitioners to understand the mechanisms whereby elevated levels of ammonia in mother or fetus results in embryonic/fetal death, growth restriction, and developmental abnormalities; and bringing, into the attention of nutritionists and practitioners, the problems of excess or inadequate dietary intake of protein or amino acids on pregnancy outcomes in animals and humans. The article provides new, effective means to improve embryonic/fetal survival and growth in mammals.
Topics: Animals; Dietary Proteins; Dietary Supplements; Fetal Development; Humans; Survival
PubMed: 29466875
DOI: 10.1177/1535370218758275 -
Nutrients Nov 2016Protein is important to the human body, and different sources of protein may have different effects on the risk of breast cancer. Thus, we conducted a meta-analysis to... (Meta-Analysis)
Meta-Analysis Review
Protein is important to the human body, and different sources of protein may have different effects on the risk of breast cancer. Thus, we conducted a meta-analysis to investigate the association between different dietary protein sources and breast cancer risk. PubMed and several databases were searched until December 2015. Relevant articles were retrieved according to specific searching criteria. Forty-six prospective studies were included. The summary relative risk (RR) for highest versus lowest intake was 1.07 (95% confidence interval (CI) 1.01-1.14, ² = 34.6%) for processed meat, 0.92 (95% CI 0.84-1.00, ² = 0%) for soy food, 0.93 (95% CI 0.85-1.00, ² = 40.1%) for skim milk, and 0.90 (95% CI 0.82-1.00, ² = 0%) for yogurt. Similar conclusions were obtained in dose-response association for each serving increase: total red meat (RR: 1.07; 95% CI 1.01-1.14, ² = 7.1%), fresh red meat (RR: 1.13; 95% CI 1.01-1.26, ² = 56.4%), processed meat (RR: 1.09; 95% CI 1.02-1.17, ² = 11.8%), soy food (RR: 0.91; 95% CI 0.84-1.00, ² = 0%), and skim milk (RR: 0.96; 95% CI 0.92-1.00, ² = 11.9%). There was a null association between poultry, fish, egg, nuts, total milk, and whole milk intake and breast cancer risk. Higher total red meat, fresh red meat, and processed meat intake may be risk factors for breast cancer, whereas higher soy food and skim milk intake may reduce the risk of breast cancer.
Topics: Animals; Breast Neoplasms; Diet, Healthy; Dietary Proteins; Egg Proteins, Dietary; Female; Humans; Incidence; Meat Products; Milk Proteins; Odds Ratio; Plant Proteins, Dietary; Poultry; Prospective Studies; Protective Factors; Recommended Dietary Allowances; Red Meat; Risk Assessment; Risk Factors; Risk Reduction Behavior; Soybean Proteins
PubMed: 27869663
DOI: 10.3390/nu8110730