Impact of increased protein intake in older adults: a 12-week double-blind randomised controlled trial.

BACKGROUND: Emerging evidence suggests health-promoting properties of increased protein intake. There is increased interest in plant protein but a dearth of information in relation to its impact on muscle function. The objective of the present work was to examine the impact of intake of different types of proteins on muscle functional parameters including handgrip strength, biomarkers of metabolic health, sleep quality and quality of life in a group of older adults. METHODS: Healthy men and women aged 50 years and older entered a double-blinded, randomised, controlled nutritional intervention study with three parallel arms: high plant protein, high dairy protein and low protein. Participants consumed once daily a ready-to-mix shake (containing 20 g of protein in high protein groups) for 12 weeks. Changes in handgrip and leg strength, body composition, metabolic health, quality of life and sleep quality were analysed by linear mixed models in an intention-to-treat approach. RESULTS: Eligible participants (n = 171) were randomly assigned to the groups (plant: n = 60, dairy: n = 56, low protein: n = 55) and 141 completed the study. Handgrip strength increased after the intervention (Ptime = 0.038), with no significant difference between the groups. There was no significant difference between groups for any other health outcomes. CONCLUSIONS: In a population of older adults, increasing protein intake by 20 g daily for 12 weeks (whether plant-based or dairy-based) did not result in significant differences in muscle function, body composition, metabolic health, sleep quality or quality of life, compared with the low protein group.

The Association between Dietary Protein Intake and Sources and the Rate of Longitudinal Changes in Brain Structure.

Few studies have examined dietary protein intake and sources, in combination with longitudinal changes in brain structure markers. Our study aimed to examine the association between dietary protein intake and different sources of dietary protein, with the longitudinal rate of change in brain structural markers. A total of 2723 and 2679 participants from the UK Biobank were separately included in the analysis. The relative and absolute amounts of dietary protein intake were calculated using a 24 h dietary recall questionnaire. The longitudinal change rates of brain structural biomarkers were computed using two waves of brain imaging data. The average interval between the assessments was three years. We utilized multiple linear regression to examine the association between dietary protein and different sources and the longitudinal changes in brain structural biomarkers. Restrictive cubic splines were used to explore nonlinear relationships, and stratified and sensitivity analyses were conducted. Increasing the proportion of animal protein in dietary protein intake was associated with a slower reduction in the total hippocampus volume (THV, ß: 0.02524, p < 0.05), left hippocampus volume (LHV, ß: 0.02435, p < 0.01) and right hippocampus volume (RHV, ß: 0.02544, p < 0.05). A higher intake of animal protein relative to plant protein was linked to a lower atrophy rate in the THV (ß: 0.01249, p < 0.05) and LHV (ß: 0.01173, p < 0.05) and RHV (ß: 0.01193, p < 0.05). Individuals with a higher intake of seafood exhibited a higher longitudinal rate of change in the HV compared to those that did not consume seafood (THV, ß: 0.004514; p < 0.05; RHV, ß: 0.005527, p < 0.05). In the subgroup and sensitivity analyses, there were no significant alterations. A moderate increase in an individual's intake and the proportion of animal protein in their diet, especially from seafood, is associated with a lower atrophy rate in the hippocampus volume.

Production of Toxins by the Gut Microbiota: The Role of Dietary Protein.

PURPOSE OF REVIEW: This narrative review will discuss how the intake of specific protein sources (animal and vegetable) providing specific amino acids can modulate the gut microbiota composition and generate toxins. A better understanding of these interactions could lead to more appropriate dietary recommendations to improve gut health and mitigate the risk of complications promoted by the toxic metabolites formed by the gut microbiota. RECENT FINDINGS: Gut microbiota is vital in maintaining human health by influencing immune function and key metabolic pathways. Under unfavorable conditions, the gut microbiota can produce excess toxins, which contribute to inflammation and the breakdown of the integrity of the intestinal barrier. Genetic and environmental factors influence gut microbiota diversity, with diet playing a crucial role. Emerging evidence indicates that the gut microbiota significantly metabolizes amino acids from dietary proteins, producing various metabolites with beneficial and harmful effects. Amino acids such as choline, betaine, l-carnitine, tyrosine, phenylalanine, and tryptophan can increase the production of uremic toxins when metabolized by intestinal bacteria. The type of food source that provides these amino acids affects the production of toxins. Plant-based diets and dietary fiber are associated with lower toxin formation than animal-based diets due to the high amino acid precursors in animal proteins.

Dietary intake of plant- and animal-derived protein and incident cardiovascular diseases: the pan-European EPIC-CVD case-cohort study.

BACKGROUND: Epidemiological evidence suggests that a potential association between dietary protein intake and cardiovascular disease (CVD) may depend on the protein source, that is, plant- or animal-derived, but past research was limited and inconclusive. OBJECTIVES: To evaluate the association of dietary plant- or animal-derived protein consumption with risk of CVD, and its components ischemic heart disease (IHD) and stroke. METHODS: This analysis in the European Prospective Investigation into Cancer and Nutrition (EPIC)-CVD case-cohort study included 16,244 incident CVD cases (10,784 IHD and 6423 stroke cases) and 15,141 subcohort members from 7 European countries. We investigated the association of estimated dietary protein intake with CVD, IHD, and stroke (total, fatal, and nonfatal) using multivariable-adjusted Prentice-weighted Cox regression. We estimated isocaloric substitutions of replacing fats and carbohydrates with plant- or animal-derived protein and replacing food-specific animal protein with plant protein. Multiplicative interactions between dietary protein and prespecified variables were tested. RESULTS: Neither plant- nor animal-derived protein intake was associated with incident CVD, IHD, or stroke in adjusted analyses without or with macronutrient-specified substitution analyses. Higher plant-derived protein intake was associated with 22% lower total stroke incidence among never smokers [HR 0.78, 95% confidence intervals (CI): 0.62, 0.99], but not among current smokers (HR 1.08, 95% CI: 0.83, 1.40, P-interaction = 0.004). Moreover, higher plant-derived protein (per 3% total energy) when replacing red meat protein (HR 0.52, 95% CI: 0.31, 0.88), processed meat protein (HR 0.39, 95% CI: 0.17, 0.90), and dairy protein (HR 0.54, 95% CI: 0.30, 0.98) was associated with lower incidence of fatal stroke. CONCLUSION: Plant- or animal-derived protein intake was not associated with overall CVD. However, the association of plant-derived protein consumption with lower total stroke incidence among nonsmokers, and with lower incidence of fatal stroke highlights the importance of investigating CVD subtypes and potential interactions. These observations warrant further investigation in diverse populations with varying macronutrient intakes and dietary patterns.

Plant proteins: are they a good alternative to animal proteins in older people?

PURPOSE OF REVIEW: This review provides the latest insight into the impact of consuming plant-based protein for older people. RECENT FINDINGS: According to the latest data, a healthy diet rich in plant-based-protein-rich-food could promote healthy aging. This health effect is partly because of the amino acid composition of proteins, as well as to the important constituents such as fiber and bioactive compounds found in the matrix. Furthermore, even though animal protein is more effective at stimulating muscle protein synthesis, a high consumption of plant protein (beyond 31 g/day) appears to enhance physical performance and reduce the risk of frailty in older individuals. SUMMARY: Recent literature highlights numerous health benefits for older people associated with a substantial intake of plant-based vs. animal-based protein, both in preventing and mitigating chronic age-related diseases and reducing the risk of all-cause mortality. However, a high intake of plant-based protein-rich products could pose risks of malnutrition and fiber-related intestinal intolerances. Further research is needed to assess the risk-benefit ratio of a high consumption of plant proteins in older individuals before we can make robust recommendations on how far animal proteins can be healthfully replaced with plant proteins.

Effect of a plant protein-rich diet on postprandial phosphate metabolism in healthy adult men: a randomised controlled trial.

BACKGROUND: This study examined the effects of animal protein- and plant protein-rich diets on postprandial phosphorus metabolism in healthy male subjects. METHODS: The study was conducted by randomised parallel-group comparison of healthy men aged 21-24 years. In Study 1, participants were divided into two groups and consumed either a 70% animal protein diet (AD, n = 6) or a 70% plant protein diet (PD, n = 6). In Study 2, participants were divided into three groups and consumed either AD (n = 10), PD (n = 10) or AD + DF, a 70% animal protein diet loaded with the same amount of fibre as PD (n = 9). The phosphorus contents of the diets used in this study were nearly equivalent (AD, 710.1 mg; PD, 709.7 mg; AD + DF, 708.9 mg). Blood and urine samples were collected before, and 2 and 4 h after the meal to measure phosphorus and calcium levels. RESULTS: In Study 1, PD consumption resulted in lower blood and urinary phosphorus concentrations 2 h postprandially compared with AD (p < 0.05). In Study 2, blood phosphorus levels in AD + DF after the diet remained lower, but not significantly so compared with AD, and urinary phosphorus levels were significantly lower 2 h postprandially (p < 0.05). CONCLUSIONS: A plant protein-rich diet reduced rapid postprandial increases in blood and urinary phosphorus concentrations compared with the animal protein-rich diets, suggesting that dietary fibre may play a partial role in the postprandial decreases in blood and urinary phosphorus concentrations.

Association of dietary protein intake, inflammation with muscle mass, physical performance and incident sarcopenia in Chinese community-dwelling older adults.

OBJECTIVES: Inflammation and impaired muscle synthesis are important factors of sarcopenia. Plant protein may reduce inflammation but may not be as efficient as animal protein in providing essential amino acids. We therefore examined the associations between dietary protein intake and changes in muscle mass and physical performance, incident sarcopenia, and the interaction effect of inflammation. DESIGN: Prospective cohort study. SETTING: The Mr. OS and Ms. OS (Hong Kong) cohort. PARTICIPANTS: A total of 2,811 sarcopenia-free participants and 569 sarcopenia participants aged ≥65 years were recruited from communities. MEASUREMENTS: Dietary protein intake was assessed using a validated food frequency questionnaire. Serum high-sensitivity C-reactive protein (hs-CRP) was measured. Linear regression examined the associations between dietary protein intake and 4-year changes in muscle mass and physical performance. Cox regression examined the association between dietary protein intake and incident sarcopenia. RESULTS: Higher plant protein intake, but not total and animal protein, was associated with less decline in muscle mass and gait speed among sarcopenia-free participants. Conversely, higher ratio of animal-to-plant protein was associated with reduced muscle mass loss among participants with sarcopenia. The highest tertile of plant protein intake was associated with lower incident sarcopenia risk (HR: 0.75, 95% CI: 0.57-0.98; P-trend = 0.034) compared to the lowest tertile. Notably, this association was observed among participants with higher serum hs-CRP levels (HR: 0.57, 95% CI: 0.34-0.95), but not in those with lower hs-CRP levels. CONCLUSION: Dietary animal and plant protein intake have differential associations with muscle mass and physical performance in older adults with and without sarcopenia. The role of plant protein in preventing sarcopenia involves modulation of inflammation.

Association between protein intake and risk of gestational diabetes mellitus: A systematic review and dose-response meta-analysis of cohort studies.

BACKGROUND: Gestational diabetes mellitus (GDM) is a common condition in pregnancy, the prevalence of which has increased. Identifying modifiable risk factors for GDM, such as dietary factors, could prevent or delay the onset of the condition. Our goal was to perform a comprehensive meta-analysis of cohort studies, to summarize the current evidence on the relationship between total, animal, and plant protein intake during pregnancy, as well as pre-pregnancy protein intake, and the risk of GDM. METHODS: A literature search was completed using Scopus, PubMed, Web of Science, and Google Scholar up to January 2023 and references of retrieved relevant articles. Observational studies examining the association between the consumption of dietary protein from different sources in pre-pregnancy or/and during pregnancy and the risk of GDM were included. To combine effect sizes for the comparison between the highest and lowest categories of protein intake, a random effects model was utilized. Dose-response relationships were investigated using a 1-stage random-effects model. RESULTS: 8 observational studies were included in the systematic review and 5 prospective cohort studies in the meta-analysis, involving a total of 24,160 participants and 2450 cases of GDM. The analysis revealed a significant association between total protein intake during pregnancy and an elevated risk of GDM (relative risk (RR): 2.24, 95 % confidence interval (CI): 1.67-3.00, P = 0.000). Conversely, no significant association was found between total protein intake before pregnancy and the risk of GDM. Both animal protein intake before pregnancy (RR: 1.47, 95 % CI: 1.06-2.03, P = 0.021) and during pregnancy (RR; 2.31, 95 % CI: 1.43-3.73, P = 0.001) showed a significant association with GDM. Interestingly, there was no significant association between the consumption of plant protein both before and during pregnancy and the risk of GDM. Further analysis revealed that an additional 5 % energy from total protein and animal protein per day was associated with a 24 % and 32 % before and 114 % and 67 % increased risk of GDM during pregnancy respectively. CONCLUSION: In conclusion, consumption of animal protein and total protein before pregnancy is associated with an increased risk of GDM, although the association is not significant for total protein. Conversely, plant protein intake is linked to a decreased risk of GDM, however, the results are not significant. The intake of any protein type (plant/animal/total) during pregnancy is associated with an elevated risk of GDM, with this association being statistically insignificant for plant protein. Further cohort studies are required to validate the findings presented in this study. REGISTRATION: PROSPERO (CRD42023396215).

Animal and vegetable protein intake and malnutrition in older adults: a multicohort study.

OBJECTIVES: Malnutrition is a global concern in older adults, as it negatively affects morbidity and mortality. While higher animal protein intake may help prevent and treat malnutrition, it might also increase the risk of chronic diseases and death. Conversely, vegetable protein intake might have a lower anabolic effect and not be as effective to improve nutritional status. We studied whether animal and vegetable protein intake are associated with changes in nutritional status in older adults. DESIGN: We used pooled data from two Spanish cohorts: the Seniors-ENRICA 1 and Seniors-ENRICA 2. SETTINGS AND PARTICIPANTS: 2,965 community-dwelling adults aged 62-92 years. MEASUREMENTS: Protein intake was estimated at baseline via an electronic, validated diet history. Nutritional status was assessed at baseline and after 2.6 years with the GLIM (Global Leadership Initiative on Malnutrition) phenotypic criteria: weight loss, low body mass index, and reduced muscle mass. The odds of improvements in nutritional status were assessed with logistic regression models, extensively adjusted for potential confounders. RESULTS: Higher animal and vegetable protein intake were associated with improvements in nutritional status [odds ratios (95% confidence intervals) per 0.25 g/kg/day were 1.15 (1.00, 1.32) and 1.77 (1.35, 2.32), respectively]. Cereal protein intake drove most of the latter association [2.07 (1.44, 2.98)]. Replacing 0.25 g/kg/day of total animal protein, meat, or fish protein (but not dairy or egg protein) with vegetable protein was associated with improvements in nutritional status [1.54 (1.13, 2.09), 1.70 (1.20, 2.41), and 1.77 (1.18, 2.64), respectively]. CONCLUSIONS: Higher animal and, especially, vegetable protein intake were associated with improvements in nutritional status in older adults. Replacing total animal protein, meat, or fish protein with vegetable protein may help improve malnutrition.

Delivery of a telehealth supported home exercise program with dietary advice to increase plant-based protein intake in people with non-alcoholic fatty liver disease: a 12-week randomised controlled feasibility trial.

This study evaluated the feasibility and safety of a telehealth delivered exercise plus plant-based protein diet in adults with non-alcoholic fatty liver disease (NAFLD). This was a 12-week, randomised controlled feasibility trial including twenty-eight adults aged > 45 years with NAFLD randomised to a home muscle strengthening program (3 d/week) with increased protein intake (target ∼1·2-1·5 g/kg/d) from predominately plant-based sources and behavioural change support (3-4 text messages/week) (Pro-Ex n 14) or usual care (UC, n 14). Feasibility was assessed via retention (≤ 10 % attrition), adherence (exercise ≥ 66 %; recommended daily protein serves ≥ 80 %) and safety (adverse events). Secondary outcomes included macronutrient intake (3 × 24-h records), weight, moderate-to-vigorous physical activity (MVPA) and 30 s sit-to-stand (STS) performance. Study retention was 89 %. Mean exercise adherence (Pro-Ex) was 52 % with one adverse event from 241 sessions. In Pro-Ex, mean daily plant protein serves increased (0·9 to 1·4/d) and animal protein decreased (1·5 to 1·2/d) after 12-weeks, but overall adherence (serves/day) was 32[RD1] % (plant) and 42 % (animal). Relative to UC, Pro-Ex experienced a mean 2·7 (95 % CI: 0·9, 4·4) increase in 30 s STS number, 46-minute (95 % CI: -153, 245) increase in MVPA, 1·7 kg (95 % CI: -3·5, 0·2) decrease in weight, 35·2 g (95 % CI: 11·0, 59·3) increase in protein. In adults with NAFLD a telehealth home exercise and dietary intervention was safe and improved habitual plant and animal protein intake, but overall adherence was modest suggesting more intensive healthcare support may be required.

Ingestion of a variety of non-animal-derived dietary protein sources results in diverse postprandial plasma amino acid responses which differ between young and older adults.

Whole-body tissue protein turnover is regulated, in part, by the postprandial rise in plasma amino acid concentrations, although minimal data exist on the amino acid response following non-animal-derived protein consumption. We hypothesised that the ingestion of novel plant- and algae-derived dietary protein sources would elicit divergent plasma amino acid responses when compared with vegan- and animal-derived control proteins. Twelve healthy young (male (m)/female (f): 6/6; age: 22 ± 1 years) and 10 healthy older (m/f: 5/5; age: 69 ± 2 years) adults participated in a randomised, double-blind, cross-over trial. During each visit, volunteers consumed 30 g of protein from milk, mycoprotein, pea, lupin, spirulina or chlorella. Repeated arterialised venous blood samples were collected at baseline and over a 5-h postprandial period to assess circulating amino acid, glucose and insulin concentrations. Protein ingestion increased plasma total and essential amino acid concentrations (P < 0·001), to differing degrees between sources (P < 0·001), and the increase was further modulated by age (P < 0·001). Postprandial maximal plasma total and essential amino acid concentrations were highest for pea (2828 ± 106 and 1480 ± 51 µmol·l-1) and spirulina (2809 ± 99 and 1455 ± 49 µmol·l-1) and lowest for chlorella (2053 ± 83 and 983 ± 35 µmol·l-1) (P < 0·001), but were not affected by age (P > 0·05). Postprandial total and essential amino acid availabilities were highest for pea, spirulina and mycoprotein and lowest for chlorella (all P < 0·05), but no effect of age was observed (P > 0·05). The ingestion of a variety of novel non-animal-derived dietary protein sources elicits divergent plasma amino acid responses, which are further modulated by age.

Enhancing Kokumi Sensation and Reducing Bitterness in Acid-Hydrolyzed Vegetable Proteins through Lactate and Thermal Processing.

Previous studies have demonstrated that thermal processing in the presence of lactate and amino acids can produce taste-active N-lactoyl amino acids. This study aimed to investigate the impact of lactate and thermal processing on the sensory characteristics of acid-hydrolyzed vegetable proteins (aHVP). The results showed that the processed aHVP exhibited enhanced kokumi, a milder umami taste, and reduced bitterness on treatment with 1% lactate at 110 °C for 3 h or 3% lactate at 120 °C for 2 h compared to the unprocessed samples. Partial or orthogonal least-squares discriminant analysis and variable importance in projection (VIP) analyses revealed the significant contributions of N-,l-Lac-l-hydrophobic AAs [-Met, -Ile, -Leu, -Val, and -Phe (VIP > 1.2)] to the observed differences between the processed and unprocessed samples. Electronic tongue analysis confirmed the sensory findings and indicated a decrease in the aftertaste of bitterness in the processed samples. Furthermore, the study identified the sensory characteristics of N-l-Lac-l-Met, -Ile, and -Leu, highlighting their potential to enhance salty, umami, and kokumi perception in simulated broth. Furthermore, the study incorporated the addition of bitter amino acids (Val, Ile, Leu, Tyr, Phe, Lys, His, and Arg) and the aforementioned N-l-Lac-l-AAs to aHVP, providing further evidence for their contributions to bitterness and aftertaste-B as well as the kokumi differences, respectively. This study provides valuable insights into the sensory effects of lactate and thermal processing on aHVP, facilitating the development of improved taste-enhancing strategies.

Effects of Animal and Vegetable Proteins on Gut Microbiota in Subjects with Overweight or Obesity.

The gut microbiota plays a pivotal role in the balance between host health and obesity. The composition of the gut microbiota can be influenced by external factors, among which diet plays a key role. As the source of dietary protein is important to achieve weight loss and gut microbiota modulation, in the literature there is increasing evidence to suggest consuming more plant proteins than animal proteins. In this review, a literature search of clinical trials published until February 2023 was conducted to examine the effect of different macronutrients and dietary patterns on the gut microbiota in subjects with overweight and obesity. Several studies have shown that a higher intake of animal protein, as well as the Western diet, can lead to a decrease in beneficial gut bacteria and an increase in harmful ones typical of obesity. On the other hand, diets rich in plant proteins, such as the Mediterranean diet, lead to a significant increase in anti-inflammatory butyrate-producing bacteria, bacterial diversity and a reduction in pro-inflammatory bacteria. Therefore, since diets rich in fiber, plant protein, and an adequate amount of unsaturated fat may help to beneficially modulate the gut microbiota involved in weight loss, further studies are needed.

Animal Protein Intake Is Associated with Obesity Remission After Roux-en-Y Gastric Bypass: an Isocaloric Replacement Analysis.

PURPOSE: Some patients do not have the expected weight loss, and the post-surgical diet may partially explain these differences. OBJECTIVES: To estimate the impact of macronutrient substitution on obesity remission after RYGB, considering the protein source. MATERIALS AND METHODS: This study included 58 patients undergoing RYGB. Data collection was performed preoperatively, 3 and 12 months after surgery. Eight participants dropped out of the study at 3 months, and the others remained for 12 months. The foods consumed were registered using a 24-h, 3-day food recall. For the isocaloric substitution analysis, foods were classified according to the protein source. The groups were compared using hypothesis tests, and Cox proportional hazard ratio regression was used to analyze isocaloric substitution. RESULTS: At three months after surgery, every 5% energy from plant protein replaced by animal protein increased by 3.50 [CI 1.204 - 10.205; p = 0.021] the probability of obesity remission. Stratified analysis by protein groups indicated that replacing vegetable protein with white meat was positively associated with remission of obesity. Every 5% vegetable protein replaced with white meat increased by 3.20 [CI 1.026 - 9.981; p = 0.045] the probability of obesity remission. Both results were independent of age, body mass index (BMI), and the presence of comorbidities. CONCLUSION: The results suggest that the consumption of animal proteins after RYGB, mainly white meat, favors weight loss.

Higher Intake of Vegetable Protein and Lower Intake of Animal Fats Reduce the Incidence of Diabetes in Non-Drinking Males: A Prospective Epidemiological Analysis of the Shika Study.

Although nutrient intake and alcohol consumption are both closely associated with the incidence of diabetes, their interrelationships remain unclear. Therefore, we herein have investigated the interrelationships among nutrient intake, alcohol consumption, and the incidence of diabetes using longitudinal data. This study included 969 residents ≥40 years living in Japan. In 2011 and 2012, a baseline study was conducted using questionnaires on basic demographics, diabetes, nutrient intake, and lifestyle habits. In 2018 and 2019, a follow-up study was performed using questionnaires and medical records on diabetes. Two-way analysis of covariance (two-way ANCOVA) was used to test the interactions of drinking habits and diabetes incidence on nutrients intake. The prospective relationship between nutrient intake at baseline and the incidence of diabetes in the follow-up stratified by drinkers and non-drinkers was evaluated using multiple logistic regression analysis. Interactions were observed for vegetable protein intake (p = 0.023) and animal fat intake (p = 0.016) in males. Vegetable protein intake negatively correlated with the incidence of diabetes in non-drinkers (odds ratio (OR): 0.208; 95% confidence interval (95% CI): 0.046-0.935; p = 0.041). Furthermore, animal fat intake positively correlated with the incidence of diabetes in non-drinkers (OR: 1.625; 95% CI: 1.020-2.589; p = 0.041). Therefore, vegetable protein and animal fat intakes in combination with drinking habits need to be considered for the prevention of diabetes.

Effects of dietary plant protein sources intake on growth, digestive enzyme activity, edible tissue nutritional status and intestinal health of the omnivorous Redclaw crayfish, Cherax quadricarinatus.

For the omnivorous Cherax quadricarinatus crayfish, plant raw materials can be good alternatives to dietary fish meal (FM). A 56-d feeding trial was conducted in C. quadricarinatus (11·70 (se 0·13) g). Diet with 100 % FM as the protein source was the control. Seven experimental diets were formulated by replacing 75 or 100 % of FM with soyabean meal (SM75, SM100) or cottonseed meal (CM75 and CM100), and a mixture of SM and CM (protein content is 1:1) replacing 50, 75 or 100 % of FM (SC50, SC75 and SC100). Crayfish fed the CM100 and SC100 showed significantly lower weight gain (WG), specific growth rate, trypsin and pepsin activities compared with the control diet. Crayfish in CM100 group showed significantly higher GPx, alanine aminotransferase, aspartate aminotransferase activities and malondialdehyde content than the control. SM100 and CM100 diets can cause slight separation of the peritrophic membrane from the intestinal folds. The pepsin activity of crayfish in SC50 was significantly higher than those in other experimental diets. The highest WG and muscle arginine content were also found in crayfish fed SC50. The relative abundance of Proteobacteria, Unclassified Enterobacteriaceae and Candidatus Bacilloplasma was significantly higher, but Actinobacteriota was significantly lower in SM100, CM100 and SC100 than in control. Microbiota functional prediction indicated that the relative abundance of 'cell motility' pathway in crayfish fed CM100 was significantly decreased compared with the control. In conclusion, only half of the FM can be effectively substituted with a mixture of SM and CM (protein content is 1:1) for C. quadricarinatus.

The value of dietary plant protein in older people.

PURPOSE OF REVIEW: The current review provides an update on recent research regarding plant-based protein and their nutritional quality for older people. RECENT FINDINGS: There is growing evidence that plant-based proteins may be a valuable strategy for older people to prevent the health risks associated with consuming animal products and to promote better protein intake, as plant-based protein sources are rich in fibres and micronutrients. Although plant-based proteins are less anabolic than animal-derived proteins due to lower digestibility and deficiencies in some essential amino acids, several innovations in food processing and nutritional strategies have been developed to improve the quality of plant-based proteins. For example, the use of protein blends or green-processes as fermentation or germination could improve the nutritional qualities of plant-based foods that could be beneficial for older people, especially to prevent sarcopenia or metabolic disorders such as diabetes, obesity and cardiovascular diseases. SUMMARY: The use of plant-based protein sources could help older people diversify their protein sources and more easily meet recommended nutritional intake. Recent literature highlights several health benefits associated with increased consumption of vegetable foods. However, their efficiency on postprandial muscle protein synthesis remains to be evaluated and long-term studies are needed.

Interfacial behavior of vegetable protein isolates at sunflower oil/water interface.

Proteins are widely used in the formation and stabilization of multiphase systems, thanks to their ability to adsorb at the interface reducing the interfacial tension and promoting the formation of viscoelastic layers. Owing to the growing consumer demand, the food industry is moving toward the growing use of plant-based proteins, suitable for consumers who do not eat products of animal origin, for either ethical or health reasons. Nevertheless, the scientific literature lacks information on the surface activity and emulsifying ability of these proteins. In this work, the interfacial properties of soy, hemp and brown rice isolate proteins were investigated at the interface with commercial sunflower oil (O/W) to evaluate their characteristics in view of potential uses in food applications such as emulsions, sauces, dressing, topping and soft foods. Dilatational and shear kinematic, with pendant drop and magnetic rod techniques, respectively, were used. The dilatational analysis was performed in static and dynamic conditions, to obtain the equilibrium adsorption isotherms and the rheological parameters of the interfacial layers under both oscillation and stress relaxation. The interfaces were studied in shear conditions with small amplitude oscillations and creep tests. The obtained results evidenced that all tested proteins are able to build a strong viscoelastic layer with properties comparable to those of animal proteins. Brown rice protein seems particularly effective in reducing the interfacial tension even if shear tests evidence that the interface is weaker than that obtained using hemp or soy protein. Hemp protein seems very promising for potential practical uses yielding intermediate interfacial tensions and strong viscoelastic layers.

Beliefs underlying older adults' intention to consume plant-based protein foods: A qualitative study.

The revised Canada's food guide released in 2019 promotes the consumption of plant-based protein foods (PBP). Yet, older adults consume little of them. This qualitative study aimed to identify older adults' beliefs about consuming PBP and to assess differences in beliefs by gender and baseline PBP consumption. Recruitment was done to obtain an equal number of men and women, 20 PBP-consumers and 40 non-consumers. Each participant completed an online questionnaire collecting sociodemographic data and took part in an individual semi-structured interview based on the Theory of Planned Behavior. A thematic analysis was performed using the Nvivo software. Health benefits, good taste and protecting the environment were perceived as advantages of consuming PBP, whereas difficulty digesting and not liking the taste were reported as disadvantages. Family members were frequently named as people who would approve and/or disapprove the consumption of PBP. Having more knowledge about PBP would facilitate consumption, while lack of motivation to change eating habits and lack of knowledge on how to prepare PBP meals were perceived barriers. Several differences in beliefs by gender and baseline PBP consumption were observed. Future interventions should focus on the beliefs that were identified as important to older adults (i.e., health benefits and food preparation skills), and should be tailored to their gender and PBP consumption.

Composition, Structure, and Techno-Functional Characteristics of the Flour, Protein Concentrate, and Protein Isolate from Purslane (Portulaca oleracea L.) Seeds.

One potential avenue to increase the production of valuable protein ingredients for the food industry is developing vegetable proteins from non-traditional plant sources. In the present study, the composition, structure and techno-functional characteristics of defatted purslane flour (DF), protein concentrate (PC), and protein isolate (AP) were investigated. The results revealed that DF, PC, and PI contained low levels of moisture, ash, and fat. However, there were significant differences (P < 0.05) in protein content between DF, PC, and PI (32.9, 60.8 and 90.9%, respectively). The techno-functional characteristics of purslane proteins were enhanced by processing purslane flour into PC and PI products. Furthermore, the ratios of total essential amino acids to total amino acids in purslane protein samples were well above that stated for ideal food proteins. SDS-PAGE analysis indicated three subunits of protein in DF, PC, and PI. Scanning electron microscopy revealed that DF exhibited a compact-like structure; PC had a small, flaky, but porous type of particle, and PI had an intact flake-like structure. The FTIR analysis revealed that some alterations in the secondary structure of protein were occurred. In summary, purslane proteins can be considered new functional food ingredients with different nutritional and technological characteristics.