Low Dietary Protein Intake Research Articles

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.

Episode of renal dysfunction in a child with eating disorder: a case report

Among the various organ dysfunctions seriously affected by eating disorders (EDs) is kidney damage. The kidneys are vital organs responsible for several essential functions, including the balance of the body's acid-base and mineral metabolism, the removal and excretion of substances, and the regulation of blood volume and pressure. Eating disorders are a widespread and clinically relevant class of multiorgan disorders that occur mainly in adolescence. EDs often have serious clinical manifestations, which are determined by electrolyte imbalance, endocrine and mental disorders, renal failure, and other disorders. Common eating disorders discussed in the literature and frequently encountered in clinical practice are anorexia nervosa and bulimia nervosa. Anorexia nervosa is a type of abnormal eating behaviour that involves the consumption of very little food and may include intentional vomiting or the misuse of laxatives or diuretics. Kidneys perform a number of vital functions to maintain homeostasis in our body. One of the main functions of the kidneys is blood filtration and the removal of metabolic products. This allows you to maintain the optimal level of fluid and electrolytes and remove toxins. Restriction of fluid intake and abuse of diuretics can cause a decrease in blood flow to the kidneys and further renal failure. The result of the latter is the development of serious violations of vital functions. Low dietary protein intake in people following a restricted diet (restrictive anorexia) leads to a decrease in glomerular filtration rate (GFR) and renal plasma flow. Treatment of acute kidney injury on the background of volume deficit due to fluid loss involves its termination and hydration orally or with the help of intravenous infusions of physiological solution depending on the severity of volume deficit and kidney damage, which was observed and described in this clinical case. Aim. To analyze the peculiarities of kidney injury in a child with an eating disorder. Materials and Methods. A detailed analysis of the case history of a pediatric patient diagnosed with eating disorder complicated with an acute episode of renal dysfunction was done. Basic anamnestic, clinical, laboratory, and instrumental data were analyzed and given in the paper. A graphic presentation is done with PowerPoint. Results. We describe a 14-year-old female patient diagnosed with ED and acute kidney injury (AKI) leading to intensive care unit interventions. Conclusions. AKIs can result from a number of conditions that are common among anorexics and include dehydration, high blood pressure, toxins, inadequate nutrition and possibly altered electrolytes. Serum creatinine, blood urea nitrogen (BUN), glomerular filtration rate (GFR), and electrolytes are among the kidney function markers that need to be monitored in the early stages of AKI linked to anorexia. The right medical care, which includes normalizing blood pressure and adequate hydration, leads to the patient's recovery. Further follow-ups on kidney function in such patients are of high importance

Effects of Dietary Intervention on Nutritional Status in Elderly Individuals with Chronic Kidney Disease.

The prevalence of chronic kidney disease (CKD) is rising, especially in elderly individuals. The overlap between CKD and aging is associated with body composition modification, metabolic abnormalities, and malnutrition. Renal care guidelines suggest treating CKD patient with a low-protein diet according to the renal disease stage. On the other hand, geriatric care guidelines underline the need for a higher protein intake to prevent malnutrition. The challenge remains of how to reconcile a low dietary protein intake with insuring a favorable nutritional status in geriatric CKD populations. Therefore, this study aims to evaluate the effect of a low-protein adequate energy intake (LPAE) diet on nutritional risk and nutritional status among elderly CKD (stage 3-5) patients and then to assess its impact on CKD metabolic abnormalities. To this purpose, 42 subjects [age ≥ 65, CKD stage 3-5 in conservative therapy, and Geriatric Nutritional Risk Index (GNRI) ≥ 98] were recruited and the LPAE diet was prescribed. At baseline and after 6 months of the LPAE diet, the following data were collected: age, sex, biochemical parameters, anthropometric measurements, body composition, and the GNRI. According to their dietary compliance, the subjects were divided into groups: compliant and non-compliant. For the compliant group, the results obtained show no increased malnutrition risk incidence but, rather, an improvement in body composition and metabolic parameters, suggesting that the LPAE diet can provide a safe tool in geriatric CKD patients.

Curcumin-resveratrol nano-formulation counteracting hyperammonemia in rats

Malnutrition and low dietary protein intake could be risk factors for developing peripheral and central hyperammonemia, especially in pediatrics. Both curcumin and resveratrol proved to be effective against several hepatic and cerebral injuries. They were reported to be beneficial in lowering circulating ammonia levels, yet both are known for their low bioavailability. The use of pharmaceutical nano-formulations as delivery systems for these two nutraceuticals could solve the aforementioned problem. Hence, the present study aimed to investigate the valuable outcome of using a combination of curcumin and resveratrol in a nanoemulsion formulation, to counteract protein-deficient diet (PDD)-induced hyperammonemia and the consequent complications in male albino rats. Results revealed that using a nanoemulsion containing both curcumin and resveratrol at a dose of (5 + 5 mg/kg) effectively reduced hepatic and brain ammonia levels, serum ALT and AST levels, hepatic and brain nitric oxide levels, oxidative DNA damage as well as disrupted cellular energy performance. In addition, there was a substantial increase in brain levels of monoamines, and a decrease in glutamate content. Therefore, it can be concluded that the use of combined curcumin and resveratrol nanoemulsion is an effective means of ameliorating the hepatic and cerebral adverse effects resulting from PDD-induced hyperammonemia in rats.

Poor Muscle Status, Dietary Protein Intake, Exercise Levels, Quality of Life and Physical Function in Women with Metastatic Breast Cancer at Chemotherapy Commencement and during Follow-Up.

This study aimed to investigate nutritional status, body composition, dietary protein intake, handgrip strength, 6 min or 4 m walk tests, self-reported physical activity, physical function, and quality of life (QoL-EORTC-QLQc30) at commencement of chemotherapy; to detect changes over time (from commencement of chemotherapy, and after 3, 6, 12, 26 and 52 weeks) in women with metastatic breast cancer (MBC); and to investigate the relationship between nutritional variables. 'Sarcopenia' was defined as low muscle mass and strength, 'myosteatosis' as muscle fat-infiltration (CT scan). Continuous variables were analysed using paired t-tests between baseline and follow-ups. Fifteen women (54y, 95% CI [46.3;61.2]) were recruited. At baseline, malnutrition was present in 3 (20%) participants, sarcopenia in 3 (20%) and myosteatosis in 7 (54%). Thirteen (87%) participants had low protein intake; low handgrip strength was observed in 0, and low walk test distance and physical activity in four (27%) participants. Physical function and QoL were low in 10 (67%) and 9 (60%), respectively. QoL between baseline and 52 weeks decreased by 11.7 (95% CI [2.4;20.9], p = 0.025). Other variables did not significantly change over time. In this small study sample, myosteatosis, low dietary protein intake, low exercise levels and impaired quality of life and physical function are common.

Prevalence and associated factors of sarcopenia in community-dwelling older adults at risk of malnutrition

BackgroundThere is an increasingly strong association between sarcopenia and malnutrition in research findings. We aimed to determine the prevalence and factors associated with sarcopenia in community-dwelling older adults (≥ 65 years) at risk of malnutrition based on Malnutrition Universal Screening Tool (MUST).MethodsThis was a cross-sectional study of 811 participants. Participants were recruited from the general population, community centers, senior activity centers, polyclinics, and hospital. Community-dwelling older adults at risk of malnutrition participated in the study. Participants’ data and measurements were collected at the baseline visit. Data included socio-demographic information, anthropometric measurements, body composition, dietary intakes, and functional assessments. Sarcopenia was defined using the Asian Working Group for Sarcopenia 2019 consensus.ResultsOf the 694 participants with complete datasets, overall prevalence of sarcopenia was 76% (n = 530); 57% (n = 393) had severe sarcopenia. In the overall cohort, compared to participants without sarcopenia, those with sarcopenia were older, had lower physical activity scale for the elderly score, leg strength, handgrip endurance, mid-upper arm circumference, calf circumference, and bone mass, and had lower dietary protein intake and poorer nutritional status (all p ≤ 0.015). After adjusting for confounders, sarcopenia was significantly associated with older age, male gender, higher risk of malnutrition, lower calf circumference, and lower bone mass (all p ≤ 0.044).ConclusionsIn community-dwelling older adults at risk of malnutrition, there is a high prevalence of sarcopenia and severe sarcopenia. As such, screening positive for either malnutrition risk or sarcopenia in older adults should prompt screening for the other risk factor, to allow early institution of disease modifying interventions to forestall adverse outcomes for both malnutrition and sarcopenia.Trial registrationThe study was registered at clinicaltrials.gov as NCT03245047.

MO931: Serum Uric Acid—A Marker of Malnutrition and Mortality in Patients Undergoing Maintenance Haemodialysis

Abstract BACKGROUND AND AIMS Malnutrition in patients on maintenance haemodialysis (HD) develops along different pathways, and factors contributing to the development of malnutrition may be categorized as of iatrogenic and non-iatrogenic origins. Iatrogenic factors are an inadvertent consequence of dialysis for HD patients (e.g. removal of uremic solutes), whereas non-iatrogenic factors develop spontaneously from different factors accompanying the progression of kidney disease but are not related to the primary treatment (e.g. low dietary energy and protein intake). Malnutrition is prevalent in 28%–54% HD patients and is an important risk factor for mortality. The aim of our study was to investigate the impact of serum uric acid (SUA) and other non-invasive markers of malnutrition on the survival of maintenance HD patients. METHOD We performed a study on 77 HD patients without malignant disease who were observed from January 2016 until their death or January 2021. Their median age was 63.0 (IQR 19) years, and their dialysis vintage was 1449 (IQR 1848) days. We recorded past medical history, laboratory tests and basic demographic data and performed bioelectrical impedance analysis with BodyStat (BodyStat Ltd). Patients who were at risk for malnutrition, based on nutrition screening tools, received oral nutritional supplements (ONS). SUA was measured every 2 months and the mean value was used for analysis. Kaplan–Meier survival analysis and Cox's regression were performed. RESULTS Included patients (51.9% males) had diabetes mellitus (33.8%), arterial hypertension (87.0%), ischemic heart disease (24.7%), chronic obstructive lung disease (3.9%), liver disease (3.9%) and were smokers (14.3%). They received an ONS in 63.6%. During the observation period, 50.6% of them died. We created tertile groups (low, medium and high) based on mean SUA &amp;lt; 294 μmol/L, 294–337 μmol/L and &amp;gt; 337 μmol/L, respectively. The low group had significantly lower body mass index (BMI) (P = 0.044), total iron binding capacity (TIBC) (P = 0.001), phase angle (P = 0.003) and dry lean mass (DLM) (P = 0.048), however there were no significant differences in prescription of ONS (P = 0.092). Kaplan–Meier survival analysis showed significantly higher mortality for patients in the low tertile group (P = 0.004). In Cox's regression model, SUA remained significant when adjusted for age, sex, BMI and comorbidities (P = 0.026). However, when adjusting for other markers of malnutrition and receiving ONS, only phase angle, albumin, DLM, fat free mass index and TIBC remained statistically significant. CONCLUSION Low SUA levels in chronic HD patients are associated with lower survival and can help identify individuals who are at risk for malnutrition. Further studies should be done to guide possible interventions.

AMINO ACID SENSING PATHWAYS IN INFLAMMATORY BOWEL DISEASE

Abstract IBD is a chronic inflammatory disease of the gastrointestinal tract affecting millions of people worldwide. The last few decades have seen rapid increase of IBD cases in the US contributing to exorbitant health-care costs and morbidity rates. IBD comprises of two major subtypes: ulcerative colitis and Crohn’s disease. Although the etiology of IBD is not completely understood, a complex interaction of environmental, genetic, immune, and gut microbial factors contributes to its pathogenesis. These factors ultimately converge to disrupt intestinal epithelial cell homeostasis, compromising mucosal barrier function, leading to unresolved relapsing inflammatory injury. Poor dietary habits such as Western diet are thought to play a pivotal role in the development of colitis. A healthy and balanced diet is important in management of the disease. Epidemiological and experimental studies demonstrate that high-protein diet triggers inflammatory flares and colitis patients are often advised to reduce animal dietary protein. However, colitis patients are also at high risk of a protein malnutrition. Thus, the precise mechanisms by which low dietary protein increases incidence of colitis and/or aggravate already established disease remains unknown. Our preliminary findings suggest that low dietary protein intake aggravated dextran sulfate sodium (DSS)-induced colitis with reduced body weight, colon length and increased histological injury. Dietary habits impact intestinal epithelial cell homeostasis and regeneration process in the event of an injury. The mechanistic target of rapamycin complex 1 (mTORC1), a ‘master’ regulator of cell growth participates in intestinal tissue regeneration. Remarkably, studies inhibiting mTORC1 activity have shown to disrupt the regenerative capacity of intestinal epithelium and increased susceptibility to colitis while activating mTORC1 had a positive effect. As amino acids potently activate mTORC1, we assessed and found that low dietary protein significantly reduce colonic mTORC1 activation. The newly discovered GAP activity towards Rags (GATOR1 &amp; GATOR2) complexes act as amino acid sensing pathways by which mTORC1 activity is modulated. GATOR1 is a negative regulator, whereas GATOR2 is a positive regulator of mTORC1. CRISPR/CAS9 knockout of Wdr24 (GATOR2) led to inactivation of mTORC1 under amino acid culture conditions. Next, we investigated the role of amino acid sensing pathway in colitis models and found that disruption of intestinal epithelial specific GATOR2 complex (Wdr24ΔIE) attenuated mTORC1 activity and increased susceptibility to colitis. These findings suggest that low protein diet impacts colitis by modulating the intestinal epithelial amino acid sensing pathway.

Adaptation and validation of a protein intake screening tool for a UK adult population.

Adequate dietary protein intake is important in human subjects for maintaining muscle turnover, determining the protein content of tissues and thus the preservation of muscle mass and function as we age. A screening tool to assess if an older individual is likely to have a lower dietary protein intake (predicted probability of protein intake ≤1⋅0 g/kg per d), has been developed for a Netherlands dietary profile, but this has not been validated in a UK population. This study aimed to adapt and then validate the protein screening tool for use in a UK population. Amendment of the tool was undertaken using data from UK BioBank and the UK National Diet and Nutrition Survey to reflect protein sources in the UK diet. Validation of the amended version of the protein screener screening tool was conducted using protein intake derived from a food frequency questionnaire (FFQ) in a sample of UK adults (n = 184) (age range 18-91 years) as the reference standard. Using the FFQ, 40% of respondents (n = 74) reported a protein intake of ≤1⋅0 g per kg body mass. The discriminative accuracy of the amended screener was tested using receiver operating characteristic (ROC) curves. The area under the curve for the ROC was 0⋅731 (95% CI 0⋅657, 0⋅805), indicating that the amended screener may be a valid tool to screen for individuals consuming ≤1⋅0 g/kg adjusted BM/d in an adult UK population. This protein screener tool is a potential method to screen individuals with a likelihood of habitually consuming protein intakes of ≤1⋅0 g/kg per d. Further validation is needed using a more robust dietary intake methodology and for specific groups, such as older adults. The screener may be applicable across healthcare, clinical and research applications.

Clinical and Dietary Determinants of Muscle Mass in Patients with Type 2 Diabetes: Data from the Diabetes and Lifestyle Cohort Twente.

Low muscle mass in patients with type 2 diabetes is associated with a progressively higher risk of morbidity and mortality. The aim of this study was to identify modifiable targets for intervention of muscle mass in type 2 diabetes. Cross-sectional analyses were performed in 375 patients of the Diabetes and Lifestyle Cohort Twente-1 study. Muscle mass was estimated by 24 h urinary creatinine excretion rate (CER, mmol/24 h). Patients were divided in sex-stratified tertiles of CER. To study determinants of CER, multivariable linear regression analyses were performed. Protein intake was determined by Maroni formula and by a semi-quantitative Food Frequency Questionnaire. The mean CER was 16.1 ± 4.8 mmol/24 h and 10.9 ± 2.9 mmol/24 h in men and women, respectively. Lower CER was significantly associated with older age (p < 0.001) as a non-modifiable risk factor, whereas higher BMI (p = 0.015) and lower dietary protein intake (both methods p < 0.001) were identified as modifiable risk factors for lower CER. Overall body mass index (BMI) was high, even in the lowest CER tertile the mean BMI was 30.9 kg/m2, mainly driven by someone’s body weight (p = 0.004) instead of someone’s height (p = 0.58). In the total population, 28% did not achieve adequate protein intake of >0.8 g/kg/day, with the highest percentage in the lowest CER tertile (52%, p < 0.001). Among patients with type 2 diabetes treated in secondary care, higher BMI and low dietary protein intake are modifiable risk factors for lower muscle mass. Considering the risk associated with low muscle mass, intervention may be useful. To that purpose, dietary protein intake and BMI are potential targets for intervention.

Nutritional and dietary interventions to prolong renal allograft survival after kidney transplantation.

Diet plays an important role in slowing progression of chronic kidney disease in native and transplanted kidneys. There is limited evidence on the association on dietary intake with renal allograft function. Mechanisms of major nutrients and dietary patterns with focusing on a plant-based diet related to kidney transplant health and longevity are reviewed. High dietary protein intake may adversely affect renal allograft. Low protein plant-focused diets such as Dietary Approaches to Stop Hypertension, plant-dominant low-protein diet and Mediterranean diets appear associated with favorable outcomes in slowing renal allograft function decline. The mechanism may be related to a change in renal hemodynamic by decreasing glomerular hyperfiltration from low dietary protein intake and plant-based ingredients. Recent observational studies of association between dietary protein intake and kidney allograft outcomes are conflicting. Although strong evidence is still lacking, a low protein diet of 0.6-0.8 g/kg/day with at least 50% of the protein source from plant-based components in kidney transplant recipients with stable kidney allograft function should be considered as the dietary target. Dietary intervention with low-protein plant-focused meals may improve outcomes in kidney transplant recipients, but the evidence remains limited and further studies are warranted.

Low Glomerular Filtration Rate in Apparently Healthy Young Individuals is an Important Factor Preventing Kidney Transplantation from Living Kidney Donors – A Single-Center Observational Study from India

Background: India performed 7936 kidney transplantation operations in 2018 with living donor as the source in 85%. Identifying a living kidney donor (LKD) is difficult due to medical, social, and regulatory barriers. In addition, only a proportion of patients who volunteer may be able to donate eventually. Despite living donors being the predominant source, there are very few studies addressing the factors influencing living donor kidney donation in India. Methods: We analyzed data from our prospective LKD registry between July 1, 2011 and June 31, 2018. Demographic details, medical history, serum creatinine, and measured glomerular filtration rate (mGFR), blood pressure and the eventual outcome of LKD evaluation, including reason for noneligibility were collected. In a prospective cohort of 12 LKDs, renal functional reserve was studied using protein loading and dietary protein intake was measured from urine urea nitrogen excretion. Results: Over a period of 81 months, 316 LKDs were enrolled in our program. On 101 instances factors related to recipients prevented transplantation and on 92 occasions donor related factors precluded donation. Among 182 medically eligible LKDs with no evidence of CKD, only 33% had mGFR &gt;90 ml/min/1.73 m2. Based on our institutional criteria, 22% of LKDs with mGFR &lt;70 ml/min/1.73 m2 were ineligible solely based this criterion. Eventually, only 32% of enrolled LKDs were accepted for donation. Dietary protein intake was low in all 12 LKDs studied, only one had mGFR &gt;90 ml/min/1.73 m2. Eight LKDs with mGFR &lt;90 ml/min/1.73 m2 showed renal functional reserve of more than 20% with protein loading. Conclusion: Only one-third of voluntary kidney donors enrolled for evaluation were eventually able to donate their kidney. Low mGFR in otherwise apparently healthy LKDs was an important reason precluding kidney donation. Only 33% of individual found medically fit for donation had a mGFR ≥90 ml/min/m2 at our center. Low dietary protein intake may be a factor contributing to low mGFR in healthy LKDs.

Dietary protein intake, kidney function, and survival in a nationally representative cohort

High-protein diets (e.g., Paleo, Atkins, South Beach, ketogenic) have gained popularity as a means to promote weight loss and avoid excess carbohydrate consumption. Yet in chronic kidney disease (CKD) patients, evidence suggests low dietary protein intake (DPI) leads to attenuation of kidney function decline, although concerns remain for risk of protein-energy wasting. To examine associations of DPI with mortality in a nationally representative cohort of US adults, stratified by kidney function. We examined the association between daily DPI scaled to actual body weight (ABW), ascertained by 24-h dietary recall, with all-cause mortality among 27,604 continuous NHANES adult participants (1999-2010), stratified according to impaired versus normal kidney function (estimated glomerular filtration rates <60 compared with ≥60 ml/min/1.72 m2, respectively), using multivariable Cox models. We also examined the relation between high biological value (HBV) protein consumption with mortality. In participants with impaired kidney function, a high DPI of≥1.4 g/kg ABW/day was associated with higher mortality, while lower DPI levels were not associated with mortality (reference, 0.6 to <1.0 g/kg ABW/day): the adjusted HRs (aHRs) were 1.09 (95% CI: 0.90, 1.32), 1.03 (95% CI: 0.82, 1.29), and 1.37 (95% CI: 1.02, 1.85) for DPI<0.6, 1.0 to <1.4, and≥1.4 g/kg ABW/day, respectively. Yet in participants with normal kidney function, a low DPI of<0.6 g/kg ABW/day was associated with higher mortality, whereas higher DPI levels were not associated with death: the aHRs were 1.18 (95% CI: 1.04, 1.34), 0.92 (95% CI: 0.81, 1.04), and 0.99 (95% CI: 0.85, 1.16) for DPI<0.6, 1.0 to <1.4, and≥1.4 g/kg ABW/day, respectively. The highest 2 tertiles of HBV consumption were associated with higher mortality in participants with impaired kidney function. Among participants with impaired kidney function, a higher DPI and greater HBV consumption were associated with higher mortality, whereas a lower DPI was associated with higher mortality in those with normal kidney function. Further studies are needed to elucidate the specific pathways between higher DPI and mortality in CKD.

Protein-Energy Wasting and Mortality Risk Prediction Among Peritoneal Dialysis Patients

Protein-energy wasting (PEW) is defined as the loss of body protein and energy reserves associated with kidney disease. However, the extent to which PEW contributes to increased mortality among peritoneal dialysis (PD) patients remains unclear. This is a retrospective cohort study from 2012 to 2020. The PEW was diagnosed by applying at least 3 of the 4 following criteria: (1) altered serum biochemistry indicated by a serum albumin level of <3.5g/L; (2) decreased body mass status identified by a body mass index (BMI) of <23kg/m2 or <10% total body fat; (3) muscle wasting defined by the lean tissue index, calculated as a lean tissue mass normalized to the height-squared in the <10th percentile of the reference population; and (4) low dietary protein intake determined by the normalized protein equivalent of a total nitrogen appearance of <0.8g/kg/day. The Malnutrition Inflammation Score (MIS) was also examined as an alternative tool for assessment of PEW. The average age of the 555 participants was 57.5±12.6years. The prevalence of PEW was 27.3%, with 196 deaths observed during the mean follow-up of 25.5months. Patients with PEW who fulfilled at least 3 of the 4 listed criteria had a higher risk of death in the unadjusted model (hazard ratio 1.61, 95% confidence interval 1.19-2.18, P=.002). However, these associations were attenuated after adjusting for potential confounders. Regarding the individual PEW criterion, decreased serum albumin and low muscle mass were significantly associated with mortality in the multivariable models. In contrast, decreased body mass and low protein intake were not associated with a higher risk of death. High MIS (≥5 points) and each one-point increase in the MIS were also significantly associated with higher risk of death in both unadjusted and adjusted models. Among PD patients, the presence of PEW was not a better predictor of all-cause mortality than either the altered serum biochemistry (albumin) or low muscle mass criteria. The MIS performed well as an independent predictor of death and might be an option for assessment of PEW status in the PD population.

Protein intake and renal function in older patients.

Chronic kidney disease (CKD) is highly prevalent in elderly patients. There is growing recognition of the importance of attention to dietary protein intake (DPI) in this population given their predisposition to age-related changes in kidney function and coexisting comorbidities (i.e., hypertension). We reviewed the impact of DPI on kidney health and survival and the role of dietary protein management in older CKD patients. While kidney function parameters including glomerular filtration rate (GFR) and renal plasma flow are slightly lower in elderly patients irrespective of CKD status, the kidneys' ability to compensate for increased DPI by augmentation of GFR is preserved until 80 years of age or less. However, long-term consumption of high DPI in individuals of older age and/or with CKD may contribute to kidney function deterioration over time. Prescription of a plant-dominant low-protein diet of 0.6-0.8 g/kg/day with more than 50% from plant sources or very low protein diets less than 0.45 g/kg/day supplemented with essential amino acids or their keto-analogues may be effective in preserving kidney function in older patients and their younger counterparts, while also monitoring for development of protein-energy wasting (PEW). Using tailored precision nutrition approaches in prescribing plant-dominant low DPI that also maintains adequate energy and nitrogen balance may ameliorate kidney function decline while also preventing development of PEW in elderly patients with CKD.

Long-term prognostic value of dietary intakes in hospitalized elderly

Rationale: Low dietary protein (DPI) and energy (DEI) intakes during hospital stay contribute to worsening nutritional status and are associated with increased short-term mortality in hospitalized elderly. We assessed the prognostic value of DPI and DEI during hospitalization in acute geriatric units (AGU), on the long-term risk of death (one year and more).

Dietary protein interventions to improve nutritional status in end-stage renal disease patients undergoing hemodialysis.

Poor nutritional status is prevalent among end-stage renal disease patients undergoing hemodialysis. Chronic hemodialysis patients show an accelerated decline in skeletal muscle mass and strength, which is associated with higher mortality rates and a reduced quality of life. The current review aims to summarize recent advances regarding underlying causes of muscle loss and interventions that support muscle mass maintenance in patients with chronic hemodialysis. Muscle maintenance in chronic hemodialysis patients is compromised by low dietary protein intake levels, anabolic resistance of skeletal muscle tissue, sedentary behavior, and amino acid removal during hemodialysis. Studies assessing the effect of increased protein intake on nutritional status generally show beneficial results, especially in hypoalbuminemic chronic hemodialysis patients. The muscle protein synthetic response following protein ingestion in chronic hemodialysis patients may be enhanced through incorporation of structured physical activity and/or concurrent ketoacid ingestion. A coordinated program that combines nutritional and physical activity interventions is likely required to attenuate the decline in muscle mass and strength of chronic hemodialysis patients. Nephrologists, dieticians, and exercise specialists should collaborate closely to establish guidelines regarding the appropriate quantity and timing of protein ingestion. In addition, they should provide tailored nutritional and physical activity interventions for chronic hemodialysis patients (see video, Supplemental Digital Content 1, Video abstract, http://links.lww.com/COCN/A14).

Association between Very Low Dietary Protein Intake and Subsequent Falls in Community-Dwelling Older Adults in the United States

Poor nutrition is linked to frailty and both poor nutrition and frailty are recognized risk factors for falls. This study examined the association between dietary protein intake and subsequent reported falls in community-dwelling older Americans with a history of falls. Other nutritional, functional, and sociodemographic-related variables were also considered in our model. This was a retrospective analysis using data from the U.S. Health and Retirement Study (HRS) and Health Care and Nutrition Study (HCNS), both funded by the U.S. National Institute on Aging. The study population (n=3,859) was community-dwelling older adults, aged >65 years, who reported ever experiencing a fall on the 2012 HRS and had also completed the 2013 HCNS and 2014 HRS. Univariable logistic models were created for all variables of interest; variables approaching statistical significance (p < 0.1) were included in the initial multivariable logistic model. Backwards selection (cut-off of p

Course and predictors of upper leg muscle strength over 48 months in subjects with knee osteoarthritis: Data from the osteoarthritis initiative

Weakness of upper leg muscles has a negative impact on future disease and functional status in subjects with knee osteoarthritis (OA). The aims of the present study were to (i) describe the course of muscle strength over 48 months and (ii) identify baseline predictors for a decline in upper leg muscle strength over time in subjects with knee OA. Data were obtained from the Osteoarthritis Initiative (OAI) database, a multicenter, observational study of knee OA. Upper leg muscle strength (in N/kg) was measured at baseline, 24 and 48 months. Potential baseline predictors included demographics, OA-specific and health and lifestyle related factors. Linear mixed model analyses were performed. A total of 1390 subjects with knee osteoarthritis were included. A statistically significant decline of muscle strength was found between baseline and 24 months (B=-0.186, 95%CI [-0.358,-0.014], p=0.03), but not between other time points (24-48 months p=0.89, and baseline and 48 months p=0.058). Predictors of a decline in muscle strength over time included demographic predictors (older age, being female, higher body mass index (BMI)), one lifestyle predictor (lower dietary protein intake) and one OA-specific predictor (radiographic severity). Muscle strength declined over time in subjects with knee OA. The identified predictors may help clinicians to select and treat subjects with knee OA at risk of a decline in muscle strength.

Sex differences in association of protein intake with loss of appendicular lean mass in older adults

A lower dietary protein intake has been associated with muscle mass loss, a decline in physical performance and more mobility limitations over time in old age. Current guidelines for protein intake advise ≥ 0.8 g/kg body weight (BW)/d, while experts propose a higher intake for older adults (1.0–1.2 g/kg BW/d), irrespective of sex. It is unknown whether the association between protein intake and loss of muscle mass is different for men and women, and whether there is an optimal protein intake to prevent this loss. Therefore, we investigated the shape of the association between protein intake and change in appendicular lean mass (aLM) over 3 years in community-dwelling older adults, separately for men and women. Data of men (n = 935) and women (n = 1061) aged 70–81 years and participating in the Health, Aging and Body Composition study were used. Dietary protein intake, measured in 1998/1999 using a food frequency questionnaire, was expressed in daily grams of protein per kg adjusted BW (g/kg aBW/d) by using healthy instead of actual BW. aLM was assessed by dual-energy X-ray absorptiometry at baseline and after 3 years. Restricted cubic spline functions with 3 knots in linear regression models were used as well as linear regression analyses. The fit of both models was compared using the likelihood ratio test. All analyses were stratified by sex and adjusted for demographics, lifestyle factors, chronic conditions, height and baseline aLM. Mean (SD) protein intake was 70.8 (26.2) g in men and 61.0 (22.5) g in women, or 0.93 (0.36) and 0.95 (0.36) g/kg aBW/d, respectively. Over 3 years, mean loss of aLM was 0.61 (1.16) kg in men and 0.35 (0.95) kg in women. In both men and women, the likelihood ratio was not significant (P = 0.57 and 0.67, respectively), indicating that the spline regression model did not fit the data better than the linear regression model. In men, the linear model showed no association between protein intake and change in aLM (adjusted B per 0.1 g/kg aBW/d = 18.1, P = 0.34). In women, a higher protein intake was associated with a smaller loss of aLM (adjusted B per 0.1 g/kg aBW/d = 34.5, P = 0.017). This study suggests a linear association between protein intake and 3-year loss of aLM in older women; however, no association was found in older men. Future studies into sex differences in associations with other physical outcomes are needed. For both sexes, an optimal protein intake could not be detected.