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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 -
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 -
Nutrients Jun 2019With the rapid growth in the aging population, there has been a subsequent increase in the rates of Alzheimer's disease and related dementias (ADRD). To combat these... (Review)
Review
With the rapid growth in the aging population, there has been a subsequent increase in the rates of Alzheimer's disease and related dementias (ADRD). To combat these increases in ADRD, scientists and clinicians have begun to place an increased emphasis on preventative methods to ameliorate disease rates, with a primary focus area on dietary intake. Protein/amino acid intake is a burgeoning area of research as it relates to the prevention of ADRD, and consumption is directly related to a number of disease-related risk factors as such low-muscle mass, sleep, stress, depression, and anxiety. As a result, the role that protein/amino acid intake plays in affecting modifiable risk factors for cognitive decline has provided a robust area for scientific exploration; however, this research is still speculative and specific mechanisms have to be proven. The purpose of this review is to describe the current understanding of protein and amino acids and the preventative roles they play with regard to ADRD, while providing future recommendations for this body of research. Additionally, we will discuss the current recommendations for protein intake and how much protein older adults should consume in order to properly manage their long-term risk for cognitive decline.
Topics: Aged; Aged, 80 and over; Amino Acids; Cognitive Aging; Cognitive Dysfunction; Dementia; Dietary Proteins; Female; Humans; Male; Risk Factors
PubMed: 31212755
DOI: 10.3390/nu11061315 -
The British Journal of Nutrition Oct 2022Although a decrease in carbohydrate intake and an increase in fat intake among Koreans have been reported, investigations of changes in protein intake have been limited....
Although a decrease in carbohydrate intake and an increase in fat intake among Koreans have been reported, investigations of changes in protein intake have been limited. Thus, this study aimed to explore trends in the dietary intake of total, plant and animal proteins overall and by socio-demographic subgroups in Korea over the past two decades. A total of 78 716 Korean adults aged ≥ 19 years who participated in the seven survey cycles of the Korea National Health and Nutrition Examination Survey 1998-2018 were included. Dietary protein intake, overall and by source, was calculated using a single 24-h dietary recall data. Changes in dietary protein over 20 years were estimated using multiple linear regression analysis after adjusting for potential covariates. For total protein intake, a significant decrease was reported from 1998 to 2016-2018 ( for trend < 0·001), whereas an increasing trend was observed from 2007-2009 to 2016-2018 ( for trend < 0·001). In terms of protein intake by source, plant protein intake decreased while animal protein intake increased over the past two decades, indicating steeper trends during the recent decade ( for trend < 0·001). These trends were more pronounced among younger adults and those with higher household income and education levels. These findings suggest that continuous monitoring of dietary protein intake overall and by source (plant . animal) across socio-demographic group is needed.
Topics: Dietary Proteins; Nutrition Surveys; Diet; Surveys and Questionnaires; Republic of Korea
PubMed: 34763739
DOI: 10.1017/S0007114521004438 -
Current Protein & Peptide Science 2017Biogenic amines in the gastrointestinal tract are important metabolites of dietary protein and amino acids with the help of gut digestive enzymes and microbes, which... (Review)
Review
Biogenic amines in the gastrointestinal tract are important metabolites of dietary protein and amino acids with the help of gut digestive enzymes and microbes, which play a crucial role in the regulation of intestinal functions, including digestion, absorption, and local immunity. However, high concentrations of biogenic amines can induce adverse reactions and are harmful to animal's health. Therefore, it is crucial to have a clear understanding of how different biogenic amines interact with a body's intestinal function signaling pathways and to monitor the content of biogenic amines in the gastrointestinal tract. And in turn, the proper concentration of dietary protein and balanced amino acids for humans and livestock could be given. Though numerous methods have been developed and improved for the detection of biogenic amines in foods or wines much less attention has been paid directly to the determination of amine levels in the gastrointestinal tract. In this article, we mainly focus on the interaction of amines with the intestinal function signaling pathway and the broad impacts on animal physiology, and our modified method to accurately and quickly detect the biogenic amines in the digesta of an animal intestine.
Topics: Animal Nutritional Physiological Phenomena; Animals; Biogenic Amines; Chromatography, High Pressure Liquid; Dietary Proteins; Gastrointestinal Tract; Intestinal Mucosa; Signal Transduction
PubMed: 27356940
DOI: 10.2174/1389203717666160627073048 -
Current Protein & Peptide Science 2019Protein is essential to growth and metabolism. Many factors influence dietary protein digestion and utilization in the gastrointestinal tract. Probiotics have attracted... (Review)
Review
Protein is essential to growth and metabolism. Many factors influence dietary protein digestion and utilization in the gastrointestinal tract. Probiotics have attracted increasing attention in recent years owing to their broad health benefits, which may include a positive influence on the digestion and utilization of proteins. Several observations support their potential role in protein digestion. For example, probiotics can regulate the intestinal microflora and thereby influence intestinal bacteria related to proteolysis. Probiotics can also induce host digestive protease and peptidase activity, and some can release exoenzymes involved in the digestion of proteins. In addition, probiotics can improve the absorption of small peptides and amino acids by improving the absorption ability of the epithelium and enhancing transport. Furthermore, probiotics can reduce harmful protein fermentation and thus decrease the toxicity of metabolites. In this review, the roles of probiotics in intestinal protein digestion and utilization and the potential mechanisms underlying these effects are discussed.
Topics: Dietary Proteins; Enzyme Activation; Gastrointestinal Microbiome; Gastrointestinal Tract; Humans; Intestinal Absorption; Peptide Hydrolases; Probiotics; Proteolysis
PubMed: 29769003
DOI: 10.2174/1389203719666180517100339 -
Physiology & Behavior Oct 2022Low-protein diets can impact food intake and appetite, but it is not known if motivation for food is changed. In the present study, we used an operant behavioral task -...
Low-protein diets can impact food intake and appetite, but it is not known if motivation for food is changed. In the present study, we used an operant behavioral task - the progressive ratio test - to assess whether motivation for different foods was affected when rats were maintained on a protein-restricted diet (REST, 5% protein diet) compared to non-restricted control rats (CON, 18% protein). Rats were tested either with nutritionally-balanced pellets (18.7% protein, Experiment 1) or protein-rich pellets (35% protein, Experiment 2) as reinforcers. Protein restriction increased breakpoint for protein-rich pellets, relative to CON rats, whereas no difference in breakpoint for nutritionally-balanced pellets was observed between groups. When given free access to either nutritionally-balanced pellets or protein-rich pellets, REST and CON rats did not differ in their intake. We also tested whether a previous history of protein restriction might affect present motivation for different types of food by assessing breakpoint of previously REST animals that were subsequently put on standard maintenance chow (protein-repleted rats, REPL, Experiment 2). REPL rats did not show increased breakpoint, relative to their initial encounter with protein-rich pellets while they were protein-restricted. This study demonstrates that restriction of dietary protein induces a selective increased motivation for protein-rich food, a behavior that disappears once rats are not in need of protein.
Topics: Animals; Appetite; Conditioning, Operant; Diet, Protein-Restricted; Dietary Proteins; Food Preferences; Motivation; Rats
PubMed: 35700813
DOI: 10.1016/j.physbeh.2022.113877 -
Food & Function Nov 2021Dietary protein has been linked with all-cause and cancer mortality. However, the relationship between dietary protein and the prognosis of hepatocellular carcinoma...
Dietary protein has been linked with all-cause and cancer mortality. However, the relationship between dietary protein and the prognosis of hepatocellular carcinoma (HCC) is still unknown. The purpose of this study was to investigate whether dietary protein intake was related to HCC mortality using data from the Guangdong Liver Cancer Cohort (GLCC), a prospective cohort study of HCC survivors established at the Sun Yat-sen University Cancer Center. Dietary information one year before the diagnosis of HCC was obtained through a 79-item semi-quantitative food frequency questionnaire (FFQ). A total of 883 patients with newly diagnosed HCC who were recruited between September 2013 and April 2017 were included in this study. The hazard ratio (HR) and 95% confidence intervals (95% CIs) were estimated by Cox proportional hazard models. The multivariate-adjusted HRs in the highest the lowest tertile of total protein intake were 0.68 (95% CI: 0.52-0.91, -trend = 0.007) for all-cause mortality and 0.74 (95% CI: 0.55-0.99, -trend = 0.040) for HCC-specific mortality. However, the associations of animal protein intake, plant protein intake, and animal-to-plant protein ratio with all-cause and HCC-specific mortality were not significant (all -trend >0.05). Our research suggests that higher prediagnostic dietary intake of total protein was associated with reduced all-cause and HCC-specific mortality.
Topics: Adult; Carcinoma, Hepatocellular; Diet; Dietary Proteins; Female; Humans; Liver Neoplasms; Male; Middle Aged; Prognosis; Prospective Studies
PubMed: 34709274
DOI: 10.1039/d1fo02013g -
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 -
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