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Current Opinion in Clinical Nutrition... Jan 2024This review underscores recent advancements in the role of protein and amino acid nutrition on cognitive health. Given the escalating prevalence of neurodegenerative... (Review)
Review
PURPOSE OF REVIEW
This review underscores recent advancements in the role of protein and amino acid nutrition on cognitive health. Given the escalating prevalence of neurodegenerative disorders, particularly Alzheimer's disease, it is essential to understand nonpharmaceutical interventions that could potentially counteract their development and progression.
RECENT FINDINGS
Emerging research indicates that moderate protein intake may offer protective benefits against dementia. Studies also emphasize the importance of considering not just the quantity, but also the quality and source of dietary protein. The role of essential amino acids in nutrition is gaining attention in the field of cognitive health. Moreover, plasma-free amino acid concentrations, particularly branched-chain amino acids, are being explored as potential biomarkers for cognitive health and Alzheimer's disease. Mechanistic studies suggest that proteins and amino acids help maintain neuronal integrity, reduce inflammation, and support muscle retention, all essential factors for cognitive health.
SUMMARY
Recent findings emphasize the complex relationship between protein, amino acids, and cognitive health, highlighting the potential of dietary interventions in warding off neurodegenerative diseases. Given the observational nature of these findings, further interventional and longitudinal studies are needed to ascertain causality and elucidate the mechanisms involved.
Topics: Humans; Alzheimer Disease; Amino Acids; Cognition; Nutritional Status; Dietary Proteins
PubMed: 37874047
DOI: 10.1097/MCO.0000000000000987 -
Advances in Kidney Disease and Health Nov 2023Low-protein diets (LPDs), usually defined as a daily dietary protein intake of 0.6 to 0.8 g/kg body weight, have been recommended for decades as a safe and effective... (Review)
Review
Low-protein diets (LPDs), usually defined as a daily dietary protein intake of 0.6 to 0.8 g/kg body weight, have been recommended for decades as a safe and effective lifestyle modification to ameliorate inflammatory damage and proteinuria, reduce glomerular hyperfiltration, and improve metabolic acidosis control in patients with chronic kidney disease (CKD). The mechanism for this is largely attributed to altered tubuloglomerular feedback and afferent arteriole contraction leading to decreased glomerular pressure. Additionally, low protein intake reduces urea generation, which can help delay dialysis initiation in advanced CKD. LPDs have different types including plant-dominant LPDs that can exert additional kidney protective effects as a result of dietary protein quality in addition to quantity. In addition, strong clinical evidence shows that a new class of diabetes mellitus medications, the sodium-glucose cotransporter 2 inhibitors, reduces albuminuria and slows the estimated glomerular filtration rate decline in CKD, even in patients without diabetes mellitus, especially if significant proteinuria is present. Given prior studies investigating the effect of LPDs used in conjunction with angiotensin pathway modulators, we argue that LPDs have a synergistic role in disease management and are expected to display additive effects when combined with sodium-glucose cotransporter 2 inhibitor usage or other pharmacologic agents. Even with medical therapy, it is prudent to implement tailored LPDs for different types of CKD.
Topics: Humans; Sodium-Glucose Transporter 2 Inhibitors; Diet, Protein-Restricted; Dietary Proteins; Renal Dialysis; Diabetes Mellitus; Renal Insufficiency, Chronic; Proteinuria; Glucose; Sodium
PubMed: 38453269
DOI: 10.1053/j.akdh.2023.12.005 -
Food & Function Mar 2024: To determine the impact of dietary protein intake and protein sources on all-cause and cardiovascular mortality of selective glomerular hypofiltration syndrome (SGHS)...
: To determine the impact of dietary protein intake and protein sources on all-cause and cardiovascular mortality of selective glomerular hypofiltration syndrome (SGHS) patients. : This study recruited participants from the National Health and Nutrition Examination Survey (NHANES) conducted between 1999 and 2004. Cox proportional hazard models and competing risk models were employed to investigate the effects of dietary protein intake and protein sources on all-cause and cardiovascular mortality in SGHS patients. Additionally, Cox regression models utilizing restricted cubic splines (RCS) were used to explore potential non-linear associations. : Over a median follow-up period of 204 months, 20.71% (449/2168) participants died, with 5.40% (117/2168) experiencing cardiovascular mortality. In the fully adjusted model, participants with the highest dietary protein intake (Q4, ≥107.13 g d) exhibited a 40% reduced risk of all-cause mortality (HR: 0.60, 95% CI: 0.39 to 0.94) and an 88% reduced risk of cardiovascular mortality (HR: 0.12, 95% CI: 0.04 to 0.35) compared to those with the lowest dietary protein intake (Q1, < 57.93 g d). Notably, non-red meat protein sources were found to reduce the risk of all-cause and cardiovascular mortality, whereas no significant association was observed with red meat consumption. : Adequate dietary protein intake has been linked to a decreased risk of all-cause and cardiovascular mortality in individuals with selective glomerular hypofiltration syndromes. This protective effect seems to be primarily associated with protein obtained from non-red meat sources.
Topics: Humans; Dietary Proteins; Nutrition Surveys; Risk Factors; Diet; Cardiovascular Diseases; Kidney Diseases
PubMed: 38363105
DOI: 10.1039/d3fo03212d -
Nutrients Nov 2023Dietary practices of masters athletes (MAs) may promote healthy ageing; however, they are poorly understood. The aims of this systematic review were to synthesise the... (Review)
Review
Dietary practices of masters athletes (MAs) may promote healthy ageing; however, they are poorly understood. The aims of this systematic review were to synthesise the literature on the dietary intakes of MAs and undertake comparisons between younger (35-50 years) and older (>50 years) MAs and the general population. A search was conducted across seven databases to identify relevant publications for screening and data extraction. Averages for energy intake (EI), macronutrients, and micronutrients were compared with data from the 2011-2012 Australian Health Survey (general population). Twenty-six studies ( = 2819) were included. Energy intake was higher for older (8908 kJ/d versus 7792 kJ/d) but not younger MAs (9073 kJ/d versus 8872 kJ/d) versus the general population. Younger versus older male MAs had higher energy and macronutrient intakes. Energy intake for older was comparable to younger female MAs (7819 kJ/d versus 7485 kJ/d), but older had higher protein, lower carbohydrate, and higher micronutrient intakes. Micronutrient intake was higher in MAs than the general population. Similar EIs for older MAs and younger general population may indicate potential for a higher-quality diet. Younger female MAs may restrict or misreport EI, requiring further investigation. There is a need for more comprehensive assessments of dietary intake in MAs to ascertain diet quality in relation to health.
Topics: Humans; Male; Female; Australia; Diet; Energy Intake; Eating; Athletes; Dietary Proteins; Micronutrients; Dietary Carbohydrates
PubMed: 38068832
DOI: 10.3390/nu15234973 -
Clinical Nutrition (Edinburgh, Scotland) Oct 2023Muscle protein synthesis (MPS) and muscle protein breakdown (MPB) are influenced through dietary protein intake and physical (in)activity, which it follows, regulate... (Review)
Review
Muscle protein synthesis (MPS) and muscle protein breakdown (MPB) are influenced through dietary protein intake and physical (in)activity, which it follows, regulate skeletal muscle (SKM) mass across the lifespan. Following consumption of dietary protein, the bio-availability of essential amino acids (EAA), and primarily leucine (LEU), drive a transient increase in MPS with an ensuing refractory period before the next MPS stimulation is possible (due to the "muscle full" state). At the same time, MPB is periodically constrained via reflex insulin actions. Layering exercise on top of protein intake increases the sensitivity of SKM to EAA, therefore extending the muscle full set-point (∼48 h), to permit long-term remodelling (e.g., hypertrophy). In contrast, ageing and physical inactivity are associated with a premature muscle full set-point in response to dietary protein/EAA and contractile activity. Of all the EAA, LEU is the most potent stimulator of the mechanistic target of rapamycin complex 1 (mTORC1)-signalling pathway, with the phosphorylation of mTORC1 substrates increasing ∼3-fold more than with all other EAA. Furthermore, maximal MPS stimulation is also achieved following low doses of LEU-enriched protein/EAA, negating the need for larger protein doses. As a result, LEU supplementation has been of long term interest to maximise muscle anabolism and subsequent net protein accretion, especially when in tandem with resistance exercise. This review highlights current knowledge vis-à-vis the anabolic effects of LEU supplementation in isolation, and in enriched protein/EAA sources (i.e., EAA and/or protein sources with added LEU), in the context of ageing, exercise and unloading states.
Topics: Humans; Leucine; Dietary Proteins; Muscle, Skeletal; Amino Acids, Essential; Mechanistic Target of Rapamycin Complex 1; Aging; Muscle Proteins
PubMed: 37625315
DOI: 10.1016/j.clnu.2023.08.010 -
Scientific Reports Nov 2023Single amino acid (AA) supplementations in foods are increasing, however their potential nutritional and physiological impacts are not fully understood. This study...
Single amino acid (AA) supplementations in foods are increasing, however their potential nutritional and physiological impacts are not fully understood. This study examined the effects of L-lysine (Lys) supplementation on protein quality of diets, serum AA concentrations and associations between the ratio of supplemental Lys to dietary protein (X) with body weight gain (BWG) in Sprague-Dawley male rats. Rats were fed one of 10 diets containing either 7% or 20% casein and supplemented with 0% (Control), 1.5%, 3%, 6% Lys or 6% Lys + 3% L-arginine (Arg) (8 rats/diet group) for 1 week. Lys supplementation reduced the protein quality of the casein-based diets (p < 0.01). BWG was reduced by supplemental Lys when X > 0.18. Free Lys supplementation dose-dependently increased serum Lys levels (p < 0.01), while increased protein-bound Lys (1.4% vs 0.52%) had little effect on serum Lys (p > 0.05). In the 7% casein diets, ≥ 1.5% supplemental Lys reduced serum alanine, asparagine, glycine, isoleucine, leucine, serine, tyrosine, valine, carnitine, ornithine, and increased urea. Supplementation of ≥ 3% Lys additionally reduced tryptophan and increased histidine, methionine and α-aminoadipic acid (α-AAA) compared to the Control (p < 0.05). In the 20% casein diets, addition of ≥ 1.5% Lys reduced serum asparagine and threonine, and ≥ 3% Lys reduced leucine, proline, tryptophan, valine, and ornithine, and 6% Lys reduced carnitine, and increased histidine, methionine, and α-AAA. Overall, this study showed that free Lys supplementation in a Lys-sufficient diet reduced the protein quality of the diets and modified the serum concentrations of many amino acids. Excess free Lys intake adversely affected growth and utilization of nutrients due to AA imbalance or antagonism. Overall lower protein intake increases susceptibility to the adverse effects of Lys supplementation.
Topics: Male; Animals; Rats; Lysine; Tryptophan; Leucine; Caseins; Histidine; Asparagine; Rats, Sprague-Dawley; Dietary Supplements; Amino Acids; Diet; Methionine; Dietary Proteins; Weight Gain; Valine; Racemethionine; Carnitine; Ornithine
PubMed: 37968448
DOI: 10.1038/s41598-023-47321-3 -
The Journal of Nutrition, Health & Aging Apr 2024Inflammation and impaired muscle synthesis are important factors of sarcopenia. Plant protein may reduce inflammation but may not be as efficient as animal protein in...
OBJECTIVES
Inflammation and impaired muscle synthesis are important factors of sarcopenia. Plant protein may reduce inflammation but may not be as efficient as animal protein in providing essential amino acids. We therefore examined the associations between dietary protein intake and changes in muscle mass and physical performance, incident sarcopenia, and the interaction effect of inflammation.
DESIGN
Prospective cohort study.
SETTING
The Mr. OS and Ms. OS (Hong Kong) cohort.
PARTICIPANTS
A total of 2,811 sarcopenia-free participants and 569 sarcopenia participants aged ≥65 years were recruited from communities.
MEASUREMENTS
Dietary protein intake was assessed using a validated food frequency questionnaire. Serum high-sensitivity C-reactive protein (hs-CRP) was measured. Linear regression examined the associations between dietary protein intake and 4-year changes in muscle mass and physical performance. Cox regression examined the association between dietary protein intake and incident sarcopenia.
RESULTS
Higher plant protein intake, but not total and animal protein, was associated with less decline in muscle mass and gait speed among sarcopenia-free participants. Conversely, higher ratio of animal-to-plant protein was associated with reduced muscle mass loss among participants with sarcopenia. The highest tertile of plant protein intake was associated with lower incident sarcopenia risk (HR: 0.75, 95% CI: 0.57-0.98; P-trend = 0.034) compared to the lowest tertile. Notably, this association was observed among participants with higher serum hs-CRP levels (HR: 0.57, 95% CI: 0.34-0.95), but not in those with lower hs-CRP levels.
CONCLUSION
Dietary animal and plant protein intake have differential associations with muscle mass and physical performance in older adults with and without sarcopenia. The role of plant protein in preventing sarcopenia involves modulation of inflammation.
Topics: Humans; Sarcopenia; Aged; Male; Female; Independent Living; Inflammation; Prospective Studies; Dietary Proteins; Muscle, Skeletal; C-Reactive Protein; Physical Functional Performance; Hong Kong; Incidence; Plant Proteins, Dietary; Animal Proteins, Dietary; Asian People; East Asian People
PubMed: 38350300
DOI: 10.1016/j.jnha.2024.100163 -
The Journal of Nutrition Dec 2023The indicator amino acid oxidation (IAAO) method has been accepted as an approach to evaluate habitual protein requirements under free-living conditions.
BACKGROUND
The indicator amino acid oxidation (IAAO) method has been accepted as an approach to evaluate habitual protein requirements under free-living conditions.
OBJECTIVES
This scoping review reports on literature that evaluated protein requirements in humans using the IAAO methods.
METHODS
Three databases (PubMed/Medline, Web of Science, and ProQuest) were systematically searched to identify studies that evaluated protein requirements using the IAAO method published in English until 5 June, 2023. We evaluated the study quality using previously developed criteria. We extracted the characteristics of the study design and the results of protein requirements. Two reviewers conducted both reviews and quality assessments independently; any differences among them were resolved by consensus or agreement of all team members.
RESULTS
We extracted 16 articles targeting children, young adults (including pregnant women, resistance training athletes, endurance-training athletes, and team sports), and older adults. In quality assessment, 14 studies were evaluated "strong," but the remaining 2 were "moderate." These studies were conducted in only 3 countries and did not include all sexes or life stages. The range of the estimated average protein requirements of each life stage was 1.30 g/kg body weight/d for children, 0.87 to 2.10 (0.87-0.93 for general young adults, 1.22-1.52 for pregnant women, 1.49-2.00 for resistance-trained athletes, 1.65-2.10 for endurance athletes, and 1.20-1.41 for team sports athletes) g/kg body weight/d for young adults, and 0.85 to 0.96 g/kg body weight/d for older adults.
CONCLUSIONS
Protein requirements in 14 studies were higher than the current reference for each sex, life stage, and physical activity that are related to protein requirements. In the future, protein requirements of various populations including sex and life stage could be assessed using the IAAO methods worldwide.
Topics: Young Adult; Child; Humans; Female; Pregnancy; Aged; Amino Acids; Nutritional Requirements; Dietary Proteins; Oxidation-Reduction; Body Weight
PubMed: 37573015
DOI: 10.1016/j.tjnut.2023.07.015 -
Animal Biotechnology Dec 2023Effects of dietary metabolizable energy (ME) and crude protein (CP) level on performance, egg quality and biochemical parameters were studied in a dual-purpose...
Effects of dietary metabolizable energy (ME) and crude protein (CP) level on performance, egg quality and biochemical parameters were studied in a dual-purpose chicken-Beijing You Chicken (BYC) at peak laying period. A 3 × 3 factorial experiment was arranged, including 3 levels of dietary ME (11.31, 11.51, 11.71 MJ/kg) and 3 levels of dietary CP (14%, 15%, 16%). The results showed that dietary CP level alone and the interaction of ME by CP affected the total feed intake (TFI) during 27-30 wks, dietary ME level affected the mortality rate of 27-34 wks of age ( = 0.018), with the highest mortality rate found in 11.31 MJ/kg group (3.10%). The albumen height (AH), Haugh unit (HU) and egg grade (EG) of 16% group was higher than those in 14% and 15% groups ( < 0.05). Serum immunoglobulin G content in 11.31 MJ/kg group was lower than in 11.51 MJ/kg and 11.71 MJ/kg groups ( = 0.037). The present study suggested that dietary levels of 11.51 MJ/kg ME and 16.0% CP are enough to maintain the performance and egg quality of BYC at peak laying period. 11.31 MJ/kg ME increased the mortality of the chicken, which may be related to the decrease of the humoral immune function and antioxidative capability.
Topics: Animals; Chickens; Animal Feed; Diet; Eating; Dietary Proteins
PubMed: 36018361
DOI: 10.1080/10495398.2022.2114001 -
Frontiers in Public Health 2023In Ethiopia, there is limited evidence on the effect of dietary protein intake on women's body mass index. Therefore, this study investigated the association between...
INTRODUCTION
In Ethiopia, there is limited evidence on the effect of dietary protein intake on women's body mass index. Therefore, this study investigated the association between dietary protein intake, diet quality, and overweight and obesity.
METHODS
A cross-sectional study was conducted among 897 women of reproductive age. Food frequency questionnaires were used to assess 7-day dietary intake. It was converted into protein and other macro-nutrient intakes, Minimum Dietary Diversity for Women, and Global Dietary Quality Score. Body Mass Index (BMI) of overweight & obese women were defined as ≥25 kg/m. An adjusted odds ratio with a 95% confidence interval (in a multivariate logistic regression model) was used to determine the strength of the association between BMI and dietary protein intake, adjusting for potential confounders.
RESULTS
The median dietary protein intake was 41.3 (32.9, 52.6) grams/day or 0.8 (0.6, 1.0) grams/kilogram of body weight/day. The prevalence of overweight and obesity was 7.5% ( = 67). Only 220 (24.5%) women could meet the recommended minimum dietary diversity of five or more food groups out of 10 per day. Furthermore, only 255 (28.4%) women were found to have a low risk for nutrient adequacy. Interestingly, women who consumed moderate dietary protein had a significantly lower likelihood of being overweight or obese, with AOR of 0.21 (95% CI 0.10-0.48). Similarly, those who consumed a high amount of protein had even lower odds, with AOR of 0.03 (95% CI 0.01-0.14), compared to those who consumed a low amount of dietary protein. Age of 40-49 years (AOR = 3.33, 95% CI 1.24-8.95) compared to 18-29 years, non-farmers (AOR = 3.21, 95% CI 1.55-6.62), higher consumption of food from unhealthy groups (AOR = 1.30, 95% CI 1.05-1.61), and high fat intake (AOR = 1.06, 95% CI 1.04-1.09) were associated with overweight and obesity.
CONCLUSIONS AND RECOMMENDATIONS
The study indicated an inverse relationship between BMI and dietary protein intake. It also revealed that women who consumed foods from unhealthy or unhealthy when consumed in excessive amounts were more likely to be overweight or obese. Increasing dietary protein consumption can help reproductive-age women reduce the odds of obesity and overweight. Furthermore, community-based educational programs, policy changes, and healthcare services can support this effort.
Topics: Humans; Female; Adult; Middle Aged; Male; Overweight; Ethiopia; Cross-Sectional Studies; Dietary Proteins; Obesity; Diet
PubMed: 38035304
DOI: 10.3389/fpubh.2023.1258515