Dietary Protein Intake Research Articles

Effects of dietary proteins on cognitive performance and brain vascular function in adults: a systematic review of randomised controlled trials.

The incidence of cognitive decline is rising, leading to increased attention on the preventive role of healthy foods on brain function. Previous reviews including primarily observational studies suggested that dietary proteins may improve cognitive performance, but evidence from individual randomised controlled trials (RCT) is less consistent. Therefore, this systematic review examined the long-term effects of dietary proteins from RCT, considering both their amount and type, on cognitive performance (psychomotor speed and attention, executive function, memory and global cognition). Alterations in cerebral blood flow (CBF) - a validated brain vascular function marker - were also considered. A total of 4747 studies were identified through a systematic search, resulting in twenty-three included papers reporting effects on cognitive performance (n = 23) and CBF (n = 3). Improvements were observed in three out of the nine studies that evaluated psychomotor speed which compared a dietary protein intervention with a non-protein or lower-protein control. Of the six beneficial observations on working memory (n = 12), declarative memory (n = 10) and visuospatial memory (n = 10), five were nut interventions from three different trials. Limited studies focusing on global cognition suggested that specific target populations, namely subacute stroke or dementia, may benefit more than healthy individuals from increased dietary protein intake. From the three studies involving CBF, improvements in regional blood flow were associated with most cognitive performance outcomes. The comparative effects of different protein types warrant further investigation. Overall, this review encourages additional research into protein-rich foods or supplements which could potentially prevent or mitigate cognitive decline.

Validity of dietary intake methods in cancer cachexia.

Accurate assessment of dietary intake, especially energy and protein intake, is crucial for optimizing nutritional care and outcomes in patients with cancer. Validation of dietary assessment methods is necessary to ensure accuracy, but the validity of these methods in patients with cancer, and especially in those with cancer cachexia, is uncertain. Validating nutritional intake is complex because of the variety of dietary methods, lack of a gold standard method, and diverse validation measures. Here, we review the literature on validations of dietary intake methods in patients with cancer, including those with cachexia, and highlight the gap between current validation efforts and the need for accurate dietary assessment methods in this population. We analyzed eight studies involving 1479 patients with cancer to evaluate the accuracy and reliability of 24-hour recalls, food records, and food frequency questionnaires in estimating energy and protein intake. We discuss validation methods, including comparison with biomarkers, indirect calorimetry, and relative validation of dietary intake methods. Few have validated dietary intake methods against objective markers in patients with cancer. While food records and 24-hour recalls show potential accuracy for energy and protein intake, this may be compromised in hypermetabolic patients. Additionally, under- and overreporting of intake may be less frequent, and the reliability of urinary nitrogen as a protein intake marker in patients with cachexia needs further investigation. Accurate dietary assessment is important for enhancing nutritional care outcomes in cachexia trials, requiring validation at multiple time points throughout the cancer trajectory.

Dietary Protein Consumption Pattern in Hyperphosphatemia Management Among Haemodialysis Patients: A Cross-Sectional Study at Kenyatta National Hospital, Kenya

Poor nutrition status in haemodialysis patients is associated with high mortality rates. A low phosphorus diet is likely to compromise dietary protein intake and nutrition status in this population. This study evaluated dietary protein consumption pattern and nutrition status among forty out-patient haemodialysis patients from Renal Unit at Kenyatta National Hospital using cross-sectional study. The Chi-square test and Kruskal‒Wallis H test were used to determine relationship between variables. More than half (58%) of the patients were male. Study participants had a mean age of 45.4±14.7 years with the majority (40%) between 40-59 years. More than three quarters (88%) had poor nutrition status with more than a third (38%) severely undernourished. More than half of the patients (53%) had dialysed for a period of more than one year. Most of study participants consumed only five types of legumes. Yellow bean, butterfly Kenyan kidney bean, butterfly haricot bean, red kidney bean and green lentil were commonly consumed legumes; 2-4 times per week by 45%, 23%, 23%, 8% and 15% of the patients respectively. Beef was the most consumed animal protein by more than half (53%) of the patients in 2-4 times a week. Second most consumed animal protein was egg white at least 2-3 times a week. Majority of the patients (58%) had poor knowledge scores (<50 % score) on food phosphorus reduction food preparation procedures in protein rich foods. This study found high prevalence of poor nutrition status and inadequate consumption of dietary protein among haemodialysis patients. This study recommends nutrition education and counseling on locally available dietary proteins and their preparation in order to meet dietary protein requirements without risk of hyperphosphatemia

Animal and plant protein intake association with mental health, tryptophan metabolites pathways, and gut microbiota in healthy women: a cross-sectional study

Mental health is affected by tryptophane (TRP) metabolism regulation. Diet-influenced gut microbiome regulates TRP metabolism. Thus, the present study aimed to explore the relationship between type of dietary protein intake, gut microbiota, TRP metabolites homeostasis, and mental well-being in healthy women. 91 healthy females aged 18–50 were recruited based on the study protocol. Validate and reliable questionnaires assessed dietary intake and mental health. Biochemical tests and gut microbiota composition were analyzed following the manufacturer’s instructions for each enzyme-linked immune sorbent assay (ELISA) kit and Real-time quantitative polymerase chain reaction (qPCR) methods respectively. Regression methods were used to estimate the considered associations. The results show that in the fully adjusted model, plant protein consumption was partially inversely associated with depression risk (OR = 0.27; 95% CI: 0.06, 1.09; P = 0.06). Higher dietary animal protein intake was marginally associated with psychological distress (OR = 2.59; 95% CI: 0.91, 7.34; P = 0.07). KYN to serotonin ratio was inversely associated with animal protein consumption (ß = 1.10; 95% CI: -0.13, 2.33; P = 0.07). Firmicutes/Bacteriodetes ratio (β = -1.27 × 103, SE = 5.99 × 102, P = 0.03) was lower in the top tertile of plant protein. A partially negative correlation was found between dietary animal protein and Prevotella abundance (β = -9.20 × 1018, SE = 5.04 × 1018, P = 0.06). Overall, significant inverse associations were found between a diet high in plant protein with mental disorders, KYN levels, and Firmicutes to Bacteroidetes ratio while adhering to higher animal protein could predispose women to psychological stress.

Improved qualities of cod-rice dual-protein gel as affected by rice protein: Insight into molecular flexibility, protein interaction and gel properties

Blending plant-based proteins with animal-based proteins to achieve adequate dietary protein intake is a strategy to address dietary deficiencies in the elderly. This research systematically investigated the effect of the ratio of cod protein/rice protein (21:0, 21:1.5, 21:3, 21:4.5, 21:6, 21:7.5, and 21:9) on the gelation properties of dual-protein gels and the underlying dual-protein interaction mechanisms. The results indicated that the myosin heavy chain (MHC) of cod and the glutelin in rice protein are primarily linked by hydrogen bonds, particularly involving Tyr residues, as evidenced by molecular docking and fluorescence quenching results. The addition of rice protein in cod protein promoted α-helix transforming into β-sheet, β-turn and random coil of the original protein solution, which was significantly correlated with molecule flexibility increasing. The decrease in the dual-protein particle size, and rice protein uniformly distributed in a cod protein-based gel network, which promoted the compactness and density of the gel structure. It was found that the hardness and springiness of 21:6 cod-rice protein gel increased by 73.96% and 17.28% compared to single cod gel, respectively. This study provides theoretical basis to the mechanism of dual-protein interaction affecting gel properties from the molecular level.

Dietary protein intake and the tubular handling of indoxyl sulfate.

Chronic kidney disease (CKD) patients are advised to limit their protein intake. A high protein diet is known to induce glomerular hyperfiltration, as well as hypertrophy of the remnant kidney, and glomerulosclerosis. Whether the diet causes changes in kidney tubule transport via gut microbiome metabolites is still unknown. We hypothesized that protein intake affects not only the intestinal generation and absorption, but also the kidney disposal of microbial amino acid metabolites. We combined data from animal models and human studies. 5/6th nephrectomy rats were administered a high (HP) or low-protein (LP) diet for 7 weeks. Plasma and urine concentration of the uremic toxins (UTs) indoxyl sulfate (IS), p-cresyl sulfate (PCS), and p-cresyl glucuronide (PCG) were measured. Their fractional excretion (FE) was calculated. The expression of kidney membrane transporters OAT1, OAT3, BCRP, OCT2 and MRP4 was analyzed. Differences in FE of UTs between individuals with higher and lower protein intake in two CKD cohorts were sought. CKD rats on an HP diet showed increased plasma levels of PCS and PCG but not IS compared to rats on a LP diet. Conversely, urinary excretion and FE of IS were higher in the HP CKD group. BCRP, MRP4 and OCT2 were not influenced by the diet. OAT1 and OAT3 were upregulated in the HP CKD group. In two independent cohorts of CKD patients, individuals with a high dietary protein intake showed a significantly higher FE of IS. A HP diet leads to a higher generation and/or absorption of aminoacid-derived UT precursors in CKD rodent models and humans, most likely via gut microbiome modulation. We demonstrate that dietary protein intake modulates transcription and expression of OAT1 and OAT3, corroborating the existence of the remote sensing and signaling hypothesis. Dietary protein intake influences kidney physiology beyond glomerular filtration.

Age-related differences in dietary protein intake in the protein-I study

Age-related differences in dietary protein intake in the protein-I study

The Independent and Additive Associations of Dietary Fiber and Protein Intake on Cardio-metabolic Health Indices and All-cause Mortality

The Independent and Additive Associations of Dietary Fiber and Protein Intake on Cardio-metabolic Health Indices and All-cause Mortality

Introducing menus of three weekly insect- or plant-based dinner meals slightly reduced meat consumption in Danish families: Results of a randomized intervention study

The environmental concerns associated with excess meat consumption have emphasized the need for sustainable alternatives. Edible insects offer a promising alternative due to their environmental efficiency and nutritious profile, but their widespread adoption in Western diets remains a challenge. The objective of the study was to investigate the impact of exposing families (parents and children) to insect-based or plant-based dinner menus on dietary pattern, meat intake, and protein intake over a six-week intervention period. The study was a two-arm randomized equivalence trial comparing an insect-based menu to a plant-based control. Families received either an insect or plant-based menu to replace meat in dinner meals three times a week for six weeks, aiming to replace 20% of their meat protein intake. Dietary changes were assessed through dietary registrations and daily questionnaires. Both adults and children maintained their estimated daily total protein intake, while reducing daily meat protein intake. Neither group met the 20% weekly meat replacement goal. In the insect-based menu group, adults and children reached an average 5.5% and 2.3% weekly meat replacement, respectively. In the plant-based menu group, adults and children replaced 9.0% and 4.3%, respectively. Meat attachment had an effect on meat protein intake. The menus slightly reduced meat protein intake. The weekly frequency of meat meals slightly declined, but portions remained the same. By enhancing insect and plant-based food quality and understanding consumer behavior, insect- and plant-based products have the potential to be a complementary alternative in a sustainable dietary transition without sacrificing nutrition. Clinical trial registryClinicalTrials.gov: NCT05156853; clinicaltrials. gov/study/NCT05156853.

High-Quality Dietary Protein: The Key to Healthy Granulation Tissue.

To review the role of nutrition and high-quality dietary protein intake in creating healthy granulation tissue and optimize wound healing in patients with chronic wounds. This continuing education activity is intended for physicians, physician assistants, nurse practitioners, and registered nurses with an interest in skin and wound care. After participating in this educational activity, the participant will:1. Summarize the structure and composition of proteins. 2. Specify the role of proteins in generating healthy granulation tissue and wound healing. 3. Explain the physiologic pathways involved in the wound healing process. 4. Describe evidence-based interventions to support nutrition in wound healing.

To evaluate dietary protein intake as per recommended dietary allowance (RDA 2020) and correlate it with the malnutrition universal screening tool score (must) in urban Indians aged 40-60 years.

To evaluate dietary protein intake as per recommended dietary allowance (RDA 2020) and correlate it with the malnutrition universal screening tool score (must) in urban Indians aged 40-60 years.

Plant-Based Dietary Protein Intake Is Associated With Lower Metabolic Syndrome Risk In Division III Female Athletes

Plant-Based Dietary Protein Intake Is Associated With Lower Metabolic Syndrome Risk In Division III Female Athletes

Nutrition and Osteoporosis Prevention.

Osteoporosis affects 50% of women and 20% of men after the age of 50. Fractures are associated with significant morbidity, increased mortality and altered quality of life. Lifestyle measures for fragility fracture prevention include good nutrition including adequate protein and calcium intakes, vitamin D sufficiency, and regular weight bearing physical exercise. Dietary protein is one of the most important nutritional considerations as it affects bone mineral density, trabecular and cortical microstructure, and bone strength. When calcium intake is sufficient, higher dietary protein intake is associated with lower risk of fracture. Dairy products are a valuable source of calcium and high quality protein. Dairy product consumption, particularly fermented dairy products, are associated with a lower risk of hip fracture and vegan diets are associated with increased fracture risk. Other dietary factors associated with reduced fracture risk include at least 5 servings per day of fruits and vegetables, regular tea drinking, adherence to a Mediterranean diet and other dietary patterns which provide fibers, polyphenols and fermented dairy products. Such dietary patterns may confer health benefits through their effect on gut microbiota composition and/or function. A balanced diet including minerals, protein, fruits and vegetables is an important element in the prevention of osteoporosis and of fragility fracture.

Apparent Saturation of Branched-Chain Amino Acid Catabolism After High Dietary Milk Protein Intake in Healthy Adults

Abstract Context Milk protein contains high concentrations of branched-chain amino acids (BCAA) that play a critical role in anabolism and are implicated in the onset of obesity and chronic disease. Characterizing BCAA catabolism in the postprandial phase could elucidate the impact of protein intake on obesity risk established in the “early protein hypothesis.” Objective To examine the acute effects of protein content of young child formulas as test meals on BCAA catabolism, observing postprandial plasma concentrations of BCAA in relation to their degradation products. Methods The TOMI Add-On Study is a randomized, double-blind crossover study in which 27 healthy adults consumed 2 isocaloric young child formulas with alternating higher (HP) and lower (LP) protein and fat content as test meals during separate interventions, while 9 blood samples were obtained over 5 hours. BCAA, branched-chain α-keto acids (BCKA), and acylcarnitines were analyzed using a fully targeted HPLC-ESI-MS/MS approach. Results Mean concentrations of BCAA, BCKA, and acylcarnitines were significantly higher after HP than LP over the 5 postprandial hours, except for the BCKA α-ketoisovalerate (KIVA). The latter metabolite showed higher postprandial concentrations after LP. With increasing mean concentrations of BCAA, concentrations of corresponding BCKA, acylcarnitines, and urea increased until a breakpoint was reached, after which concentrations of degradation products decreased (for all metabolites except valine and KIVA and Carn C4:0-iso). Conclusion BCAA catabolism is markedly influenced by protein content of the test meal. We present novel evidence for the apparent saturation of the BCAA degradation pathway in the acute postprandial phase up to 5 hours after consumption.

A Systematic Review of the Effect of Gene-Lifestyle Interactions on Metabolic-Disease-Related Traits in South Asian Populations.

Recent data from the South Asian subregion have raised concern about the dramatic increase in the prevalence of metabolic diseases, which are influenced by genetic and lifestyle factors. The aim of this systematic review was to summarize the contemporary evidence for the effect of gene-lifestyle interactions on metabolic outcomes in this population. PubMed, Web of Science, and SCOPUS databases were searched up until March 2023 for observational and intervention studies investigating the interaction between genetic variants and lifestyle factors such as diet and physical activity on obesity and type 2 diabetes traits. Of the 14 783 publications extracted, 15 were deemed eligible for inclusion in this study. Data extraction was carried out independently by 3 investigators. The quality of the included studies was assessed using the Appraisal Tool for Cross-Sectional Studies (AXIS), the Risk Of Bias In Non-randomized Studies-of Interventions (ROBINS-I), and the methodological quality score for nutrigenetics studies. Using a narrative synthesis approach, the findings were presented in textual and tabular format. Together, studies from India (n = 8), Pakistan (n = 3), Sri Lanka (n = 1), and the South Asian diaspora in Singapore and Canada (n = 3) reported 543 gene-lifestyle interactions, of which 132 (∼24%) were statistically significant. These results were related to the effects of the interaction of genetic factors with physical inactivity, poor sleep habits, smoking, and dietary intake of carbohydrates, protein, and fat on the risk of metabolic disease in this population. The findings of this systematic review provide evidence of gene-lifestyle interactions impacting metabolic traits within the South Asian population. However, the lack of replication and correction for multiple testing and the small sample size of the included studies may limit the conclusiveness of the evidence. Note, this paper is part of the Nutrition Reviews Special Collection on Precision Nutrition. PROSPERO registration No. CRD42023402408.

Maternal dietary protein and amino acid intake is not associated with the amino acid composition of human milk in an affluent environment.

Amino acids (AA) are essential nutrients in human milk (HM) and critical for infant growth and development. Several maternal lifestyle factors have been suggested to influence HM AA composition, with possible consequences for the breastfed infant. Whether maternal dietary protein and AA intake is associated with AA concentrations in HM is still largely unknown. Therefore, the aim of this study was to investigate the association between maternal dietary AA intake and AA concentrations in HM over the first month postpartum. Data from the observational longitudinal Amsterdam Mother's Milk study were used, consisting of 123 lactating women in their first postpartum month. HM samples were collected three times, on day 10, 17 and 24 postpartum. Maternal dietary protein and AA intake on these collection days was assessed using three 24-h recalls. HM protein-bound and free AA (BAA and FAA, respectively) were analysed by liquid chromatography. Associations between maternal AA intake and AA concentrations in HM were assessed using linear mixed models. Maternal intake was negatively associated with milk concentrations of free arginine (-0·0003; P = 0·01) and free lysine (-0·0004; P = 0·03) and was positively associated with free glutamine (0·002; P = 0·03) and free threonine (0·0008; P = 0·03). However, these associations were attenuated after correction for multiple testing. Both the quality and quantity of dietary protein intake in lactating women do not seem to influence the amino composition of their breast milk when living in an affluent environment.

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

Low protein intake and physical inactivity are factors that associated with muscle deterioration and poor physical performance among older adults. To assess the association between dietary protein intake and physical fitness tests among older adults with pre-sarcopenia and sarcopenia. 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. Most of the subjects have low household income (<RM 3030) (90%), Malay ethnicity (66.4%), and are married (64.5%). 74.55% of the subjects were pre-sarcopenic, whereas 25.45% were sarcopenic. Those with sarcopenia were mostly underweight (± 21.78 kg/m2), whereas those with pre-sarcopenia had a slightly higher Body Mass Index (BMI) (± 27.30 kg/m2). Both men and women did not meet the dietary protein requirement (± 43.86 g/ day) based on the Recommended Nutrient Intake (RNI) of 2017. Moreover, both pre-sarcopenic and sarcopenic subjects have reduced functional ability. Although no significant differences were found in the Short Physical Performance Battery (SPPB) score, those with sarcopenia had poorer physical performance than those with pre-sarcopenia (82.1% versus 69.5%). Apart from that, there was a significant association between the 2-min step test (2MST) and dietary protein intake among those with pre-sarcopenia (r-value = 0.252). In conclusion, lifestyle interventions among older adults are important, including ensuring adequate protein intake and encouraging appropriate physical activity to enhance muscle mass, strength, and performance to improve their daily life efficiency and quality of life.

Dietary protein defends lean mass and maintains the metabolic benefits of glucagon receptor agonism in mice

ObjectiveGlucagon has long been proposed as a component of multi-agonist obesity therapeutics due to its ability to induce energy expenditure and cause weight loss. However, chronic glucagon-receptor agonism has been associated with a reduction in circulating amino acids and loss of lean mass. Importantly, it is currently not known whether the metabolic benefits of glucagon can be maintained under contexts that allow the defence of lean mass. MethodsWe investigate the metabolic effects of the long-acting glucagon receptor agonist, G108, when administered to obese mice at low-doses, and with dietary protein supplementation. ResultsDietary protein supplementation can only fully defend lean mass at a low dose of G108 that is sub-anorectic and does not reduce fat mass. However, in this context, G108 is still highly effective at improving glucose tolerance and reducing liver fat in obese mice. Mechanistically, liver RNA-Seq analysis reveals that dietary protein supplementation defends anabolic processes in low-dose G108-treated mice, and its effects on treatment-relevant glucose and lipid pathways are preserved. ConclusionGlucagon-mediated energy expenditure and weight loss may be mechanistically coupled to hypoaminocidemia and lean mass loss. However, our data suggest that glucagon can treat MAFLD at doses which allow full defence of lean mass given sufficient dietary protein intake. Therefore, proportionate glucagon therapy may be safe and effective in targeting hepatocytes and improving in glycaemia and liver fat.

Context-dependent impact of the dietary non-essential amino acid tyrosine on Drosophila physiology and longevity.

Dietary protein intake modulates growth, reproduction, and longevity by stimulating amino acid (AA)-sensing pathways. Essential AAs are often considered as limiting nutrients during protein scarcity, and the role of dietary non-essential AAs (NEAAs) is less explored. Although tyrosine has been reported to be crucial for sensing protein restriction in Drosophila larvae, its effect on adult physiology and longevity remains unclear. Here, using a synthetic diet, we perform a systematic investigation of the effect of single NEAA deprivation on nutrient-sensing pathways, reproductive ability, starvation resistance, feeding behavior, and life span in adult female flies. Specifically, dietary tyrosine deprivation decreases internal tyrosine levels and fecundity, influences AA-sensing machineries, and extends life span. These nutritional responses are not observed under higher total AA intake or in infertile female flies, suggesting a context-dependent influence of dietary tyrosine. Our findings highlight the unique role of tyrosine as a potentially limiting nutrient, underscoring its value for dietary interventions aimed at enhancing health span.

Estimating Dietary Protein and Sodium Intake with Sodium Removal in Peritoneal Dialysis Patients.

An increase in dietary protein intake (DPI) carries a risk with respect to increased sodium intake, which further leads to the development of cardiovascular morbidity in peritoneal dialysis (PD) patients. Dialytic (DSR) and urinary sodium removal (USR) are potential indicators of sodium intake. In this single-center cross-sectional study with 60 prevalent PD patients, we analyze the correlation of DPI with sodium intake and the association between residual renal function (RRF) and comorbidity grade, expressed as the Davies score with sodium removal and protein metabolism indices such as normalized protein catabolic rate (nPCR) and lean body mass (LBM). The value of RRF < 2 mL/min/1.73 m2 is significantly associated with lower USR (p = 0.000) and lower %LBM (p < 0.001). The greatest USR is detected in patients with low Davies comorbidity grade (p = 0.018). Compared to patients with DPI < 0.8 g/kg/day, patients with DPI > 0.8 g/kg/day have a greater sodium intake (3.69 ± 0.71 vs. 2.94 ± 0.86; p < 0.018) and a greater nPCR (p < 0.001). Protein intake is significantly correlated with sodium intake (p = 0.041), but not with total sodium removal (TSR). A strong correlation is observed between sodium intake and TSR (p = 0.000), although single TSR values are not the same as the corresponding sodium intake values. An increasing protein intake implies the necessity to determine both sodium intake and sodium removal. Preservation of RRF has a beneficial role not just in sodium removal, but also in the increase of LBM.