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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 -
Nature Reviews. Endocrinology Jan 2020Dietary protein is crucial for human health because it provides essential amino acids for protein synthesis. In addition, dietary protein is more satiating than... (Review)
Review
Dietary protein is crucial for human health because it provides essential amino acids for protein synthesis. In addition, dietary protein is more satiating than carbohydrate and fat. Accordingly, many people consider the protein content when purchasing food and beverages and report 'trying to eat more protein'. The global market for protein ingredients is projected to reach approximately US$90 billion by 2021, largely driven by the growing demand for protein-fortified food products. This Perspective serves as a caution against the trend of protein-enriched diets and provides an evidence-based counterpoint that underscores the potential adverse public health consequences of high protein intake.
Topics: Dietary Proteins; Energy Intake; Food, Fortified; Humans; Prediabetic State; Risk Factors
PubMed: 31728051
DOI: 10.1038/s41574-019-0274-7 -
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 -
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 -
Nutrition Research Reviews Jun 2023
Review
Topics: Humans; Aged; Diet; Nutritional Requirements; Health Status; Dietary Proteins
PubMed: 34919036
DOI: 10.1017/S0954422421000408 -
Nestle Nutrition Institute Workshop... 2013Skeletal muscle hypertrophy is a beneficial adaptation for many individuals. The metabolic basis for muscle hypertrophy is the balance between the rates of muscle... (Review)
Review
Skeletal muscle hypertrophy is a beneficial adaptation for many individuals. The metabolic basis for muscle hypertrophy is the balance between the rates of muscle protein synthesis (MPS) and muscle protein breakdown (MPB), i.e. net muscle protein balance (NMPB = MPS - MPB). Resistance exercise potentiates the response of muscle to protein ingestion for up to 24 h following the exercise bout. Ingestion of many protein sources in temporal proximity (immediately before and at least within 24 h after) to resistance exercise increases MPS resulting in positive NMPB. Moreover, it seems that not all protein sources are equal in their capacity to stimulate MPS. Studies suggest that ∼20-25 g of a high-quality protein maximizes the response of MPS following resistance exercise, at least in young, resistance-trained males. However, more protein may be required to maximize the response of MPS with less than optimal protein sources and/or with older individuals. Ingestion of carbohydrate with protein does not seem to increase the response of MPS following exercise. The response of inactive muscle to protein ingestion is impaired. Ingestion of a high-quality protein within close temporal proximity of exercise is recommended to maximize the potential for muscle growth.
Topics: Diet; Dietary Proteins; Exercise; Humans; Hypertrophy; Muscle Proteins; Muscle, Skeletal; Resistance Training
PubMed: 23899756
DOI: 10.1159/000350259 -
JAMA- To review published and presented data on the relationship between dietary protein and blood pressure in humans and animals. (Review)
Review
OBJECTIVE
- To review published and presented data on the relationship between dietary protein and blood pressure in humans and animals.
DATA SOURCES
- Bibliographies from review articles and books on diet and blood pressure that had references to dietary protein. The bibliographies were supplemented with computerized MEDLINE search restricted to English language and abstracts presented at epidemiologic meetings.
STUDY SELECTION
- Observational and intervention studies in humans and experimental studies in animals.
DATA EXTRACTION
- In human studies, systolic or diastolic blood pressure were outcome measures, and dietary protein was measured by dietary assessment methods or by urine collections. In animal studies, blood pressure and related physiological effects were outcome measures, and experimental treatment included protein or amino acids.
DATA SYNTHESIS
- Historically, dietary protein has been thought to raise blood pressure; however, studies conducted in Japan raised the possibility of an inverse relationship. Data analyses from subsequent observational studies in the United States and elsewhere have provided evidence of an inverse relationship between protein and blood pressure. However, intervention studies have mostly found no significant effects of protein on blood pressure. Few animal studies have specifically examined the effects of increased dietary protein on blood pressure.
CONCLUSIONS
- Because of insufficient data and limitations in previous investigations, better controlled and adequately powered human studies are needed to assess the effect of dietary protein on blood pressure. In addition, more research using animal models, in which experimental conditions are highly controlled and detailed mechanistic studies can be performed, is needed to help provide experimental support for or against the protein-blood pressure hypothesis.
Topics: Animals; Blood Pressure; Clinical Trials as Topic; Diet, Protein-Restricted; Dietary Proteins; Evaluation Studies as Topic; Humans; Hypertension
PubMed: 8622252
DOI: 10.1001/jama.1996.03530440078040 -
Nutrients Jul 2023Fibroblast growth factor 21 (FGF21), a hormone predominantly released in the liver, has emerged as a critical endocrine signal of dietary protein intake, but its role in...
Fibroblast growth factor 21 (FGF21), a hormone predominantly released in the liver, has emerged as a critical endocrine signal of dietary protein intake, but its role in the control of estrous cyclicity by dietary protein remains uncertain. To investigated the role of FGF21 and hypothalamic changes in the regulation of estrous cyclicity by dietary protein intake, female adult Sprague-Dawley rats with normal estrous cycles were fed diets with protein contents of 4% (P4), 8% (P8), 13% (P13), 18% (P18), and 23% (P23). FGF21 liver-specific knockout or wild-type mice were fed P18 or P4 diets to examine the role of liver FGF21 in the control of estrous cyclicity. Dietary protein restriction resulted in no negative effects on estrous cyclicity or ovarian follicular development when the protein content was greater than 8%. Protein restriction at 4% resulted in decreased bodyweight, compromised -1 expression in the hypothalamus, disturbed estrous cyclicity, and inhibited uterine and ovarian follicular development. The disturbed estrous cyclicity in rats that received the P4 diet was reversed after feeding with the P18 diet. Liver mRNA expressions and serum FGF21 levels were significantly increased as dietary protein content decreased, and loss of hepatic FGF21 delayed the onset of cyclicity disruption in rats fed with the P4 diet, possibly due to the regulation of insulin-like growth factor-1. Collectively, severe dietary protein restriction results in the cessation of estrous cyclicity and ovarian follicle development, and hepatic FGF21 and hypothalamic -1 were partially required for this process.
Topics: Rats; Mice; Female; Animals; Dietary Proteins; Kisspeptins; Rats, Sprague-Dawley; Estrous Cycle; Fibroblast Growth Factors; Liver
PubMed: 37447375
DOI: 10.3390/nu15133049 -
The American Journal of Clinical... Sep 2003High dietary protein intakes are known to increase urinary calcium excretion and, if maintained, will result in sustained hypercalciuria. To date, the majority of... (Review)
Review
High dietary protein intakes are known to increase urinary calcium excretion and, if maintained, will result in sustained hypercalciuria. To date, the majority of calcium balance studies in humans have not detected an effect of dietary protein on intestinal calcium absorption or serum parathyroid hormone. Therefore, it is commonly concluded that the source of the excess urinary calcium is increased bone resorption. Recent studies from our laboratory indicate that alterations in dietary protein can, in fact, profoundly affect intestinal calcium absorption. In short-term dietary trials in healthy adults, we fixed calcium intake at 20 mmol/d while dietary protein was increased from 0.7 to 2.1 g/kg. Increasing dietary protein induced hypercalciuria in 20 women [from 3.4 +/- 0.3 ( +/- SE) during the low-protein to 5.4 +/- 0.4 mmol/d during the high-protein diet]. The increased dietary protein was accompanied by a significant increase in intestinal calcium absorption from 18.4 +/- 1.3% to 26.3 +/- 1.5% (as determined by dual stable isotopic methodology). Dietary protein intakes at and below 0.8 g/kg were associated with a probable reduction in intestinal calcium absorption sufficient to cause secondary hyperparathyroidism. The long-term consequences of these low-protein diet-induced changes in mineral metabolism are not known, but the diet could be detrimental to skeletal health. Of concern are several recent epidemiologic studies that demonstrate reduced bone density and increased rates of bone loss in individuals habitually consuming low-protein diets. Studies are needed to determine whether low protein intakes directly affect rates of bone resorption, bone formation, or both.
Topics: Adult; Aged; Bone and Bones; Calcium; Dietary Proteins; Female; Homeostasis; Humans; Male; Middle Aged; Osteoporosis
PubMed: 12936953
DOI: 10.1093/ajcn/78.3.584S -
Comprehensive Reviews in Food Science... Jan 2023During food processing and storage, proteins are sensitive to oxidative modification, changing the structural characteristics and functional properties. Recently, the... (Review)
Review
During food processing and storage, proteins are sensitive to oxidative modification, changing the structural characteristics and functional properties. Recently, the impact of dietary protein oxidation on body health has drawn increasing attention. However, few reviews summarized and highlighted the impact of oxidative modification on the nutritional value of dietary proteins and related mechanisms. Therefore, this review seeks to give an updated discussion of the effects of oxidative modification on the structural characteristics and nutritional value of dietary proteins, and elucidate the interaction with gut microbiota, intestinal tissues, and organs. Additionally, the specific mechanisms related to pathological conditions are also characterized. Dietary protein oxidation during food processing and storage change protein structure, which further influences the in vitro digestion properties of proteins. In vivo research demonstrates that oxidized dietary proteins threaten body health via complicated pathways and affect the intestinal microenvironment via gut microbiota, metabolites, and intestinal morphology. This review highlights the influence of oxidative modification on the nutritional value of dietary proteins based on organs and the intestinal tract, and illustrates the necessity of appropriate experimental design for comprehensively exploring the health consequences of oxidized dietary proteins.
Topics: Dietary Proteins; Oxidation-Reduction; Nutritive Value; Diet; Oxidative Stress
PubMed: 36527316
DOI: 10.1111/1541-4337.13090