Opposing GPCR signaling programs protein intake setpoint in Drosophila.

Animals defend a target level for their fundamental needs, including food, water, and sleep. Deviation from the target range, or "setpoint," triggers motivated behaviors to eliminate that difference. Whether and how the setpoint itself is encoded remains enigmatic for all motivated behaviors. Employing a high-throughput feeding assay in Drosophila, we demonstrate that the protein intake setpoint is set to different values in male, virgin female, and mated female flies to meet their varying protein demands. Leveraging this setpoint variability, we found, remarkably, that the information on the intake setpoint is stored within the protein hunger neurons as the resting membrane potential. Two RFamide G protein-coupled receptor (GPCR) pathways, by tuning the resting membrane potential in opposite directions, coordinately program and adjust the protein intake setpoint. Together, our studies map the protein intake setpoint to a single trackable physiological parameter and elucidate the cellular and molecular mechanisms underlying setpoint determination and modulation.

Greater Protein Intake Emphasizing Lean Beef Does Not Affect Resistance Training-Induced Adaptations in Skeletal Muscle and Tendon of Older Women: A Randomized Controlled Feeding Trial.

BACKGROUND: Although experimental research supports that resistance training (RT), especially with greater dietary protein intake, improves muscle mass and strength in older adults, comparable research on tendons is needed. OBJECTIVES: We assessed the effects of a protein-rich diet emphasizing lean beef, compared with 2 control diets, on RT-induced changes in skeletal muscle and tendon size and strength in older women. METHODS: We randomly assigned women [age: 66 ± 1 y, body mass index (BMI): 28 ± 1] to groups that consumed 1) 0.8 g total protein/kg body weight/day from mixed food sources (normal protein control, n = 16); 2) 1.4 g/kg/d protein from mixed food sources (high protein control, n = 17); or 3) 1.4 g/kg/d protein emphasizing unprocessed lean beef (high protein experimental group, n = 16). Participants were provided with all foods and performed RT 3 times/wk, 70% of 1-repetition maximum for 12 wk. We measured quadriceps muscle volume via magnetic resonance imaging (MRI). We estimated patellar tendon biomechanical properties and cross-sectional area (CSA) using ultrasound and MRI. RESULTS: Dietary intake did not influence RT-induced increases in quadriceps strength (P < 0.0001) or muscle volume (P < 0.05). We noted a trend for an RT effect on mean tendon CSA (P = 0.07), with no differences among diets (P > 0.05). Proximal tendon CSA increased with RT (P < 0.05) with no difference between dietary groups (P > 0.05). Among all participants, midtendon CSA increased with RT (P ≤ 0.05). We found a decrease in distal CSA in the 0.8 g group (P < 0.05) but no change in the 1.4 g group (P > 0.05). Patellar tendon MRI signal or biomechanical properties were unchanged. CONCLUSIONS: Our findings indicated that greater daily protein intake, emphasizing beef, did not influence RT-induced changes in quadriceps muscle strength or muscle volume of older women. Although we noted trends in tendon CSA, we did not find a statistically significant impact of greater daily protein intake from beef on tendon outcomes. This trial was registered at clinicaltrials.gov as NCT04347447.

Daily Dietary Protein Distribution Does Not Influence Changes in Body Composition During Weight Loss in Women of Reproductive Years with Overweight or Obesity: A Randomized Controlled Trial.

BACKGROUND: Preservation of fat-free mass (FFM) during intentional weight loss is challenging yet important to maintain a resting metabolic rate. A balanced protein distribution of 25-30 g per meal improves 24-h muscle protein synthesis, which may promote FFM maintenance and greater reductions in fat mass (FM) during weight loss in women. OBJECTIVES: We aimed to determine whether the daily dietary protein distribution pattern during energy restriction influences changes in body composition in women of reproductive age. We hypothesized that evenly distributing protein across meals compared with the usual intake pattern of consuming most of the protein at the dinner meal would be superior in preserving FFM while reducing FM during weight loss. METHODS: Healthy women (n = 43) aged 20-44 y with a BMI of 28-45 kg/m2 completed a randomized parallel feeding study testing 2 patterns of daily protein intake (even distribution across all meals compared with a skewed distribution with most protein consumed at the evening meal). Participants completed an 8-wk controlled 20% energy restriction (all foods provided), followed by an 8-wk self-choice phase in which participants were asked to maintain a similar diet and dietary pattern when purchasing and consuming their own foods. Body composition was measured at baseline, week 8, and week 16. Data were analyzed using mixed models. Statistical significance was set at P < 0.05. Data are presented as differences in least squares means ± SE. RESULTS: No significant main effects of group or group-by-time interactions were observed. All measures exhibited the main effect of time (P < 0.001). Overall, body weight, FFM, FM, and body fat percentage decreased 5.6 ± 0.4, 1.0 ± 0.2, 4.6 ± 0.4 kg, and 2.3 ± 0.2%, respectively, during this 16-wk study. CONCLUSION: Daily dietary protein distribution at a fixed protein level does not appear to influence changes in body composition during weight loss in women of reproductive age. CLINICAL TRIAL REGISTRY NUMBER AND WEBSITE WHERE IT WAS OBTAINED: NCT03202069 https://classic. CLINICALTRIALS: gov/ct2/show/NCT03202069.

Protein Adequacy, Plant Protein Proportion, and Main Plant Protein Sources Consumed Across Vegan, Vegetarian, Pescovegetarian, and Semivegetarian Diets: A Systematic Review.

BACKGROUND: There are several types of plant-based diets, with unknown differences across diets on total/plant protein intake and variety of plant protein sources consumed. OBJECTIVES: This systematic review aimed to compare total protein intake, proportion of plant proteins, and main plant protein sources consumed across 4 primarily plant-based diets: vegan, vegetarian, pescovegetarian, and semivegetarian. METHODS: We included observational studies reporting on protein intake and/or protein sources in generally healthy adults that were published between 2002 and 2023. We determined the following: 1) % energy from total and plant protein; 2) the proportion of plant protein relative to total protein intake; and 3) main plant protein sources (median percentage contribution of each source to total plant protein intake; interquartile range) consumed across the 4 diets. The plant protein sources were broadly classified into the following United States Department of Agriculture food groups: grains; nuts and seeds; soy products; and beans, peas, and lentils. RESULTS: We included 13 studies reporting on protein intake/sources that were conducted in the United States, Europe, and South Korea. Of these, 7 reported on vegan, 11 on vegetarian, 7 on pescovegetarian, and 7 on semivegetarian diets with total protein intake ranging from 10% to 17.4%. Vegan diets had the highest plant protein proportion (range: 77%-98%) and semivegetarian diets the lowest (range: 37%-83%). Plant protein source contribution was the highest from grains (range: 60%-78%). Nuts and seeds were the most consumed in vegetarian diets (7.9%; 2.9%-10.3%) and least in semivegetarian diets (3.7%; 2%-14.8%). Soy products and beans, peas, and lentils were most consumed in vegan diets (17.3%; 16.3%-19.9, and 19.6%; 14.6%-21.3, respectively) and least in semivegetarian (3.7%; 1.3%-13.9%, and 8.5%; 5.2%-10.2%) diets. CONCLUSIONS: Vegan diets has the highest plant protein proportion and a variety of plant protein sources, while semivegetarian diets has the lowest plant protein proportion and mainly relied on grains as a plant protein source.

Dietary protein and amino acid intakes for mitigating sarcopenia in humans.

Adult humans generally experience a 0.5-1%/year loss in whole-body skeletal muscle mass and a reduction of muscle strength by 1.5-5%/year beginning at the age of 50 years. This results in sarcopenia (aging-related progressive losses of skeletal muscle mass and strength) that affects 10-16% of adults aged ≥ 60 years worldwide. Concentrations of some amino acids (AAs) such as branched-chain AAs, arginine, glutamine, glycine, and serine are reduced in the plasma of older than young adults likely due to insufficient protein intake, reduced protein digestibility, and increased AA catabolism by the portal-drained viscera. Acute, short-term, or long-term administration of some of these AAs or a mixture of proteinogenic AAs can enhance blood flow to skeletal muscle, activate the mechanistic target of rapamycin cell signaling pathway for the initiation of muscle protein synthesis, and modulate the metabolic activity of the muscle. In addition, some AA metabolites such as taurine, ß-alanine, carnosine, and creatine have similar physiological effects on improving muscle mass and function in older adults. Long-term adequate intakes of protein and the AA metabolites can aid in mitigating sarcopenia in elderly adults. Appropriate combinations of animal- and plant-sourced foods are most desirable to maintain proper dietary AA balance.

Cross-sectional relationship between dietary protein intake, energy intake and protein energy wasting in chronic kidney disease patients.

The potential threshold for dietary energy intake (DEI) that might prevent protein-energy wasting (PEW) in chronic kidney disease (CKD) is uncertain. The subjects were non-dialysis CKD patients aged ≥ 14 years who were hospitalised from September 2019 to July 2022. PEW was measured by subjective global assessment. DEI and dietary protein intake (DPI) were obtained by 3-d diet recalls. Patients were divided into adequate DEI group and inadequate DEI group according to DEI ≥ 30 or < 30 kcal/kg/d. Logistic regression analysis and restricted cubic spline were used in this study. We enrolled 409 patients, with 53·8 % had hypertension and 18·6 % had diabetes. The DEI and DPI were 27·63 (sd 5·79) kcal/kg/d and 1·00 (0·90, 1·20) g/kg/d, respectively. 69·2 % of participants are in the inadequate DEI group. Malnutrition occurred in 18·6 % of patients. Comparing with patients in the adequate DEI group, those in the inadequate DEI group had significantly lower total lymphocyte count, serum cholesterol and LDL-cholesterol and a higher prevalence of PEW. For every 1 kcal/kg/d increase in DEI, the incidence of PEW was reduced by 12·0 % (OR: 0·880, 95 % CI: 0·830, 0·933, P < 0·001). There was a nonlinear curve relationship between DEI and PEW (overall P < 0·001), and DEI ≥ 27·6 kcal/kg/d may have a preventive effect on PEW in CKD. Low DPI was also significantly associated with malnutrition, but not when DEI was adequate. Decreased energy intake may be a more important factor of PEW in CKD than protein intake.

Protein intake and body weight, fat mass and waist circumference: an umbrella review of systematic reviews for the evidence-based guideline on protein intake of the German Nutrition Society.

PURPOSE: This umbrella review aimed to assess whether dietary protein intake with regard to quantitative (higher vs. lower dietary protein intake) and qualitative considerations (total, plant-based or animal-based protein intake) affects body weight (BW), fat mass (FM) and waist circumference (WC). METHODS: A systematic literature search was conducted in PubMed, Embase and Cochrane Database of Systematic Reviews for systematic reviews (SRs) with and without meta-analyses of prospective studies published between 04 October 2007 and 04 January 2022. Methodological quality and outcome-specific certainty of evidence of the retrieved SRs were assessed by using AMSTAR 2 and NutriGrade, respectively, in order to rate the overall certainty of evidence using predefined criteria. RESULTS: Thirty-three SRs were included in this umbrella review; 29 were based on randomised controlled trials, a few included cohort studies. In studies without energy restriction, a high-protein diet did not modulate BW, FM and WC in adults in general (all "possible" evidence); for older adults, overall certainty of evidence was "insufficient" for all parameters. Under hypoenergetic diets, a high-protein diet mostly decreased BW and FM, but evidence was "insufficient" due to low methodological quality. Evidence regarding an influence of the protein type on BW, FM and WC was "insufficient". CONCLUSION: "Possible" evidence exists that the amount of protein does not affect BW, FM and WC in adults under isoenergetic conditions. Its impact on the reduction in BW and FM under hypoenergetic conditions remains unclear; evidence for an influence of protein type on BW, FM and WC is "insufficient".

Screening for protein energy wasting in children with chronic kidney disease using dual energy x-ray absorptiometry as an additional tool.

BACKGROUND: The current diagnosis of protein energy wasting (PEW) is based on scoring systems that lack precision in measuring muscle deficits. We undertook this cross-sectional study to determine the prevalence of PEW in children with chronic kidney disease (CKD) using a scoring system that included dual energy x-ray absorptiometry (DEXA) for measuring lean body mass (LBM) and to determine the prevalence of selected markers in PEW. METHODS: Thirty CKD and 20 healthy children (1-18 years) were evaluated for (1) reduced dietary protein intake (DPI); (2) BMI < fifth centile for height age (BMI/HA); (3) serum albumin < 3.8 g/dl, cholesterol < 100 mg/dl, or CRP > 3 mg/L; (4) LBM < fifth centile for height age [LBMr] on DEXA. PEW was scored as minimal-one parameter positive in 2/4 categories; standard-one parameter positive in 3/4 categories; or modified-standard plus height < 2 SD. RESULTS: Twenty children with CKD (66.7%) had PEW, (5/9) 55% in CKD 3, and (15/21) 71% in advanced CKD; minimal 12, standard 1, and modified 7. LBMr was seen in 20 (100%), reduced DPI in 16 (80%), and BMI/HA in 6 (30%) children with PEW. LBMr had 100% sensitivity and BMI/HA 100% specificity. LBMr was seen in 8 who had no other criteria for PEW. None of the parameters were positive in controls (p < 0.01). CONCLUSIONS: PEW prevalence in CKD was high. Both prevalence and severity were higher in advanced CKD. LBMr was a highly sensitive marker to detect PEW. LBMr seen in some children with CKD who were negative for other markers could represent subclinical PEW.

Protein intake and its relationship with frailty in chronic kidney disease.

INTRODUCTION: Patients with chronic kidney disease (CKD) are susceptible to frailty because of a range of nutrition-related factors. While protein restriction is commonly advised to preserve kidney function in patients with CKD, insufficient protein intake could potentially exacerbate frailty risk. This study aimed to elucidate the relationship between frailty and protein intake in patients with CKD. METHODS: This cross-sectional study enrolled patients with CKD stage 3-5. Frailty and prefrailty were assessed using the Japanese version of the Cardiovascular Health Study (J-CHS) criteria. To estimate dietary protein intake, Maroni's formula based on 24-h urine collection was used. The potential association between frailty/pre-frailty and protein intake was investigated using a logistic regression analysis. RESULTS: Ninety-seven individuals with CKD were included in the study, with a median age of 73.0 years (interquartile range: 67.0, 82.0). Among them, 34 were women (35.1%), and the estimated glomerular filtration rate (eGFR) was 36.3 mL/min/1.73 m2 (interquartile range: 26.9, 44.1). Frailty and pre-frailty were identified in 13.4% and 55.7% of participants, respectively. Comparing the groups, protein intake in the frailty/pre-frailty group (0.83 g/kgBW/day [0.72, 0.93]) was lower than that in the robust group (0.89 g/kgBW/day [0.84, 1.19], p = 0.002). Upon logistic regression analysis, protein intake exhibited an independent association with frailty/pre-frailty (odds ratio: 0.72, 95% confidence interval: 0.59-0.89, p = 0.003). CONCLUSION: Reduced protein intake in patients with CKD is associated with frailty and pre-frailty. It is advisable to ensure that patients with CKD who are at risk of frailty consume an adequate amount of protein.

Dietary Intake and Nutritional Status in Diabetic and Nondiabetic Patients With Chronic Kidney Disease Stage 4-5 (NutriDiab Study).

OBJECTIVES: The aim of the present study was to assess the dietary intake and nutritional status of patients with chronic kidney disease (CKD) stage 4-5 according to the presence of diabetes. METHODS: This observational and cross-sectional study included adult patients with CKD stage 4-5 referred to a nephrology unit, between October 2018 and March 2019. Daily dietary intake was evaluated by 24-hour dietary inquiry and urine excretion. Nutritional status was assessed by measuring body composition using bioimpedance analysis and muscle function using handgrip strength. Undernutrition was considered using the protein energy wasting score. RESULTS: A total of 75 CKD patients were included, 36 (48%) of whom had diabetes; median age (interquartile range) was 71 (60-80) years. The median weight-adjusted dietary energy intake (DEI) was 22.6 (19.1-28.2) kcal/kg/day and the mean weight-adjusted dietary protein intake (DPI) was 0.86 ± 0.19 g/kg/day. There was no significant difference in DEI and DPI between patients with diabetes and those without, except for weight-adjusted DPI which was significantly lower in diabetic patients (P = .022). In univariate analysis, diabetes was associated with weight-adjusted DPI (coefficient [95% confidence interval] -0.237 [-0.446; -0.004] kcal/kg/day; P = .040), but this association did not remain significant in multivariate analysis. Nutritional status did not differ significantly between diabetic and nondiabetic patients except for lean tissue mass, which was lower in diabetic patients (P = .046). The proportion of patients with protein energy wasting was not significantly different between diabetic and nondiabetic patients (13.9% vs. 10.2%, respectively). CONCLUSIONS: In the present cohort, DPI and DEI were not significantly different between diabetic and nondiabetic CKD patients. Diabetes was not found to be associated with dietary intakes in CKD stage 4-5 patients.

Assessment of Nutritional Intake in Patients With Kidney Failure Treated by Haemodialysis on Dialysis and Non-dialysis Days.

INTRODUCTION/AIMS/OBJECTIVE: Inadequate nutritional intake in haemodialysis (HD) patients increases the risk of muscle wasting, nutrient deficiencies, leading to an increased risk of additional morbidity and mortality. We aimed to assess nutritional intake on the dialysis day and nondialysis day (NDD) of patients established on HD. METHODS: We employed a 2-day dietary record, one on the day of dialysis and one on the NDD, and then determined nutritional intake using the Nutritics software. Muscle strength was assessed by hand grip strength, and the body composition was determined using multifrequency bioelectrical impedance recorded postdialysis. RESULTS: We recruited 51 established HD patients dialysing between May 2022 and July 2022, of mean age 60 ± 15 years, 52.9% male, and 51% diabetic. Only 25% achieved the calorie and protein intake recommended by Kidney Disease Outcomes Quality Initiative. Most patients had inadequate consumption of fiber (96%), calcium (86%), iron (80%), zinc (82%), selenium (92%), folate (82%), vitamin A (88%), and (100%) vitamin D. On the other hand, the great majority followed the restriction guidelines for potassium (96%), phosphorus (86%), and sodium (84%), respectively. However, consumption was greater for potassium (P = .007), phosphorus (P = .015), and zinc (P = .032) on NDDs versus dialysis days, but there was no difference in protein or calorie intake between days. CONCLUSION: Our results suggest that many of our HD patients do not achieve the recommended nutritional targets. Patient compliance with restricting sodium, potassium, and phosphate limits protein and calorie intake. HD patients are at increased risk of sarcopenia, so failure to achieve dietary protein intake will further increase this risk.

The impact of energy and protein intake on rehabilitation efficiency in convalescent patients.

BACKGROUND AND OBJECTIVES: It is well known that more than 40% of patients in the convalescent rehabilitation settings suffer from malnutrition, and that appropriate nutrition management can improve rehabilitation outcomes. METHODS AND STUDY DESIGN: In this study, we used a change in motor score of Functional Independent Measure (FIM-M) of convalescent rehabilitation to investigate whether daily energy intake could influence the rehabilitation outcomes. Of the 217 patients hospitalized in our convalescent rehabilitation ward (CRW) between September 2016 and February 2017, 162 met the eligibility criteria for this study. RESULTS: For a 25 kcal/ ideal body weight (IBW)/day cutoff point, 76 patients consumed more than 25 kcal/IBW/day of energy (H-E group), and 86 patients consumed up to 25 kcal/IBW/day of energy (L-E group). Patients in the L-E group had poorer nutritional status than those in the H-E group at CRW admission. Moreover, patients in the L-E group lost some body weight (BW) during hospitalization, whereas patients in the H-E group gained some BW. Furthermore, the FIM-M efficiency in the L-E group was significantly lower than that in the H-E group. CONCLUSIONS: We concluded that appropriate nutritional management given to rehabilitation patients for adequate energy intake to maintain or gain their BW could maximize the outcome of convalescent rehabilitation.

Effect of Protein Supplementation Combined With Resistance Training in Gait Speed in Older Adults: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

BACKGROUND: We aimed to evaluate the effectiveness of the combination of protein supplementation and resistance training (RT), compared with RT alone or combined with a placebo, in improving gait speed. METHODS: We searched PubMed, Web of Science, Cochrane Library, and SPORTDiscus databases, and 18 randomized controlled trials with 1,147 older participants were included for meta-analysis. Data were pooled as the effect sizes (Hedges' g) with 95% confidence interval (CI) of the gait speed (in meters per second). The random-effect meta-analysis, subgroup analyses, meta-regression, and sensitivity analysis were conducted. RESULTS: The combination of protein supplementation and RT significantly improved gait speed (Hedges' g: 0.52 m/s, 95% confidence interval [0.17, 0.86], p = .005; I2 = 86.5%) compared with the RT alone. The subgroup analyses revealed that the significant improvement in gait speed postprotein intervention plus RT was observed only in participants who consumed protein after RT (Hedges' g: 0.90 m/s, 95% confidence interval [0.46, 1.33], p = .001; I2 = 79.6%). The pooled result did not significantly change after excluding any single study at one time or excluding smaller studies with large effect sizes. CONCLUSIONS: Protein supplementation combined with RT could significantly improve the gait speed of older adults compared with RT alone. This positive effect is more pronounced in people who consume protein after RT.

Dietary protein intake and its association with physical fitness test among older adults with pre-sarcopenia and sarcopenia: A cross-sectional study.

BACKGROUND: Low protein intake and physical inactivity are factors that associated with muscle deterioration and poor physical performance among older adults. AIM: To assess the association between dietary protein intake and physical fitness tests among older adults with pre-sarcopenia and sarcopenia. METHODS: A total of 110 older adults were recruited through a convenience sampling method. Data including sociodemography, anthropometry, body composition, medical history, and dietary protein intake were obtained through the interview-administered method. RESULTS: Most of the subjects have low household income (

Evaluating Therapy and Growth in Children with Phenylketonuria: A Retrospective Longitudinal Study from Two Romanian Centers.

Background and Objectives: Phenylketonuria (PKU) is a rare genetic disorder characterized by the inability to convert the essential amino acid phenylalanine into tyrosine. Early dietary treatment can successfully prevent complications, but controversies still exist regarding the attainment of normal growth in these patients. Materials and Methods: Eighteen patients with PKU from two Romanian reference centers were compared to eighteen non-PKU controls, matched for age and gender. The comparisons used weight-for-height, weight-for-age, height/length-for-age, and body mass index-for-age z-scores from birth to three years of age. Results: The PKU study group consisted of nine boys and nine girls, with a median follow-up period of thirty-six months (interquartile range = 9.75). While median values of all four growth metrics remained within the normal range across the entire study period, weight-for-age z-scores were significantly lower in PKU patients throughout most of the study (p < 0.001). Conclusions: The persistent lower weight-for-age z-scores of the PKU patients compared to controls indicate that ongoing monitoring and potential adjustments in dietary therapy may be necessary to further optimize growth outcomes.

Association of Plant Protein Intake With Risk of Incident CKD: A UK Biobank Study.

RATIONALE & OBJECTIVE: Data suggest that various dietary interventions slow kidney disease progression and improve clinical outcomes for those with chronic kidney disease (CKD). However, the association between plant protein intake and incident CKD has been uncertain. STUDY DESIGN: Prospective cohort study. SETTING & PARTICIPANTS: 117,809 participants who completed at least 1 dietary questionnaire and had an estimated glomerular filtration rate (eGFR) ≥ 60mL/min/1.73m2, a urinary albumin-creatinine ratio (UACR)<30mg/g, and no history of CKD. EXPOSURE: Daily plant protein intake in g/kg/day. OUTCOME: Incident CKD based on the International Classification of Diseases, 10th Revision (ICD-10) or the Office of Population Censuses and Surveys Classification of Interventions and Procedures, version 4 (OPCS-4) codes. ANALYTICAL APPROACH: A cause-specific proportional hazards analysis incorporating competing risks that treated death occurring before incident CKD as a competing event. RESULTS: During a median follow-up period of 9.9 years, incident CKD occurred in 3,745 participants (3.2%; incidence rate, 3.2 per 1,000 person-years). In a multivariable model, the adjusted hazard ratio (AHR) for the second, third, and highest quartiles of plant protein intake was 0.90 (95% CI, 0.82-0.99), 0.83 (95% CI, 0.75-0.92), and 0.82 (95% CI, 0.73-0.93), respectively, compared with the lowest quartile. Modeled as a continuous variable, the AHR per 0.1g/kg/day plant protein intake increase was 0.96 (95% CI, 0.93-0.99). This beneficial association was also consistent in secondary analyses for which CKD was defined based on codes or 2 consecutive measures of eGFR<60mL/min/1.73m2 or UACR>30mg/g. Various sensitivity analyses demonstrated consistent findings. LIMITATIONS: Potential incomplete dietary assessments; limited generalizability due to the characteristics of participants in the UK Biobank Study. CONCLUSIONS: In this large, prospective cohort study, greater dietary plant protein intake was associated with a lower risk of incident CKD. Further interventional studies demonstrating the kidney-protective benefits of plant protein intake are warranted. PLAIN-LANGUAGE SUMMARY: Plant-based diets confer various health benefits, including lowering the risk of cardiovascular disease and certain cancers. However, the relationship between plant protein intake and the risk of chronic kidney disease (CKD) remains unclear. Our study investigated the association between plant protein intake and the development of CKD. Using the UK Biobank Study data, we found that participants with a higher plant protein intake had a lower risk of developing CKD. Our finding suggests that a higher dietary intake of plant-based protein may be beneficial for kidney health and provides insight into dietary interventions to prevent CKD in primary care settings.

Low selenium intake is associated with risk of all-cause mortality in kidney transplant recipients.

BACKGROUND: Deficiency of the essential trace element selenium is common in kidney transplant recipients (KTR), potentially hampering antioxidant and anti-inflammatory defence. Whether this impacts the long-term outcomes of KTR remains unknown. We investigated the association of urinary selenium excretion, a biomarker of selenium intake, with all-cause mortality; and its dietary determinants. METHODS: In this cohort study, outpatient KTR with a functioning graft for longer than 1 year were recruited (2008-11). Baseline 24-h urinary selenium excretion was measured by mass spectrometry. Diet was assessed by a 177-item food frequency questionnaire, and protein intake was calculated by the Maroni equation. Multivariable linear and Cox regression analyses were performed. RESULTS: In 693 KTR (43% men, 52 ± 12 years), baseline urinary selenium excretion was 18.8 (interquartile range 15.1-23.4) µg/24-h. During a median follow-up of 8 years, 229 (33%) KTR died. KTR in the first tertile of urinary selenium excretion, compared with those in the third, had over a 2-fold risk of all-cause mortality [hazard ratio 2.36 (95% confidence interval 1.70-3.28); P < .001], independent of multiple potential confounders including time since transplantation and plasma albumin concentration. The most important dietary determinant of urinary selenium excretion was protein intake (Standardized ß 0.49, P < .001). CONCLUSIONS: Relatively low selenium intake is associated with a higher risk of all-cause mortality in KTR. Dietary protein intake is its most important determinant. Further research is required to evaluate the potential benefit of accounting for selenium intake in the care of KTR, particularly among those with low protein intake.

Dietary protein requirements and recommendations for healthy older adults: a critical narrative review of the scientific evidence.

Adequate protein intake is essential for the maintenance of whole-body protein mass. Different methodological approaches are used to substantiate the evidence for the current protein recommendations, and it is continuously debated whether older adults require more protein to counteract the age-dependent loss of muscle mass, sarcopenia. Thus, the purpose of this critical narrative review is to outline and discuss differences in the approaches and methodologies assessing the protein requirements and, hence, resulting in controversies in current protein recommendations for healthy older adults. Through a literature search, this narrative review first summarises the historical development of the Food and Agriculture Organization/World Health Organization/United Nations University setting of protein requirements and recommendations for healthy older adults. Hereafter, we describe the various types of studies (epidemiological studies and protein turnover kinetic measurements) and applied methodological approaches founding the basis and the different recommendations with focus on healthy older adults. Finally, we discuss important factors to be considered in future studies to obtain evidence for international agreement on protein requirements and recommendations for healthy older adults. We conclude by proposing future directions to determine 'true' protein requirements and recommendations for healthy older adults.

Dietary protein intake and all-cause mortality: results from The Kawasaki Aging and Wellbeing Project.

BACKGROUND: Increased protein intake has been recommended to prevent sarcopenia/frailty, reports on the quantity and quality of protein intake needed and the associated prognosis, particularly in the aging population of Asia, are limited. In this study, we aimed to investigate the relationship between protein intake and mortality in Japanese individuals, aged 85 years and older. METHODS: The data were obtained from The Kawasaki Aging and Wellbeing Project, which is a prospective cohort study of older adults aged between 85 and 89 years with no physical disability at baseline. Of the 1,026 adults in the cohort, 833 were included in the analysis, after excluding those who had not completed a brief, self-administered diet history questionnaire or those who scored less than 24 on the Mini-Mental State Examination. The participants were grouped into quartiles based on protein intake: Q1 (protein < 14.7, %Energy), Q2 (14.7 ≤ protein < 16.7, %Energy), Q3 (16.7 ≤ protein < 19.1, %Energy), and Q4 (≥ 19.1, %Energy). Multivariate Cox proportional hazards models were utilized to evaluate the association between protein intake and all-cause mortality. Kaplan-Meier survival curves were employed to investigate the relationship between protein intake and all-cause mortality. RESULTS: The mean protein intake of our study population was 17.0% of total energy. Animal protein intake, particularly fish intake, increased significantly along with total protein intake. The study had an average observation period of 1,218 days and recorded 89 deaths. After adjusting for age, sex, skeletal muscle mass index, cardiovascular disease, cancer, education, and serum albumin levels, a lower risk of all-cause mortality was observed in the highest protein intake (Q4) group than in the lowest protein intake (Q1) group (hazard ratio: 0.44, 95% confidence interval: 0.22-0.90, p-value: 0.020). CONCLUSION: Protein intake is associated with a reduced risk of all-cause mortality in older adults (aged ≥ 85 years) who engage in independent activities of daily living. This association may impact all-cause mortality independent of muscle mass.

Relationship between protein intake and grip strength in qualitative and quantitative aspects among the elderly in Korea: results from the Korea National Health and Nutrition Examination Survey.

BACKGROUND: This study investigated the association between quantitative and qualitative protein intake and grip strength (GS) in the South Korean population to explore nutritional management for the prevention of sarcopenia. METHODS: This cross-sectional study was based on data from a nationally representative sample of the South Korean elderly population, consisting of 1,531 men and 1,983 women aged 65 years and older who participated in the Korean National Health and Nutrition Examination Survey from 2016 to 2019. Low GS was defined as GS < 28 kg in men and GS < 18 kg in women. Protein intake was assessed using 1-day 24-h recall, and we analyzed absolute protein intake, protein intake by food source, and protein intake compared to dietary reference intake with per body weight or absolute daily recommended value. RESULTS: The total and animal protein intake and protein intake from legumes, fish and shellfish were significantly lower in women with a low GS than in those with a normal GS. After adjusting for confounding factors, women who consumed more protein than the estimated average requirement (EAR, 40 g/day for women) were 0.528 times less likely to have low GS than women consuming less protein than the EAR (95% CI: 0.373-0.749), and consuming any amount of protein from legumes were 0.656 times less likely (95% CI: 0.500-0.860) to have low GS than women who did not consume any amount of legume protein. CONCLUSIONS: This study provides epidemiological evidence that adequate protein intake above EAR and protein intake from legumes should be guided for preventing low GS, especially in elderly women.