Research Progress on New Functions of Animal and Plant Proteins

Protein is composed of peptides, essential nutrients for human survival and health, and the easy absorption of peptides further promotes human health. According to the source of the protein, it can be divided into plants, animals, and micro-organisms, which have important physiological effects on the health of the body, especially in enhancing immunity. The most widely used raw materials are animal protein and plant protein, and the protein composition formed by the two in a certain proportion is called "double protein". In recent years, China's State Administration for Market Regulation has issued an announcement on the "Implementation Rules for the Technical Evaluation of New Functions and Products of Health Foods (Trial)", which provides application conditions and listing protection for the research and development of new functions of health foods. At present, some researchers and enterprises have begun to pay attention to the potential of animal and plant proteins to be used in new functions. In this article, the research progress of animal and plant proteins in the new functions of Chinese health food is reviewed in detail, and suggestions for future research on animal and plant proteins are put forward.

Association between plant and animal proteins intake with lipid profile and anthropometric indices: A cross-sectional study

BACKGROUND

Results of studies on the effects of plant and animal proteins on lipid profile are controversial. So we aimed to assess the relationship between plant and animal protein intake with lipid profile and novel anthropometric indices in healthy individuals.

METHOD

In this cross-sectional study, 236 participants have selected from Shiraz medical centers (Iran) through random cluster sampling. Food intakes were assessed using a 168-items food frequency questionnaire (FFQ). Total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and triglyceride (TG) were measured. Anthropometric indices including a body shape index (ABSI), abdominal volume index (AVI), buddy roundness index (BRI), and conicity index (CI) were calculated.

RESULTS

In the crude and fully adjusted models, more consumption of plant proteins was associated with TG levels (OR = 2.31; 95% CI: 1.08, 4.95; P = 0.03 and OR = 2.39; 95% CI: 1.03, 5.15; P = 0.04). Also, there was a significant direct association between plant proteins and BRI in the curd model (OR = 3.55; 95% CI: 1.32, 9.54; P = 0.01), and after adjusting for age and energy intake (OR = 3.32; 95% CI: 1.21, 9.14; P = 0.01). More consumption of plant proteins was related to higher CI in the crude model (OR = 3.06; 95% CI: 1.12, 8.31; P = 0.03), but not in the fully adjusted model.

CONCLUSION

We found that a higher intake of plant proteins was associated with a higher TG level, BRI, and CI index. However, more research is needed to confirm these relations and provide the evidence needed to exert these findings into clinical practice.

Dual cryoprotective and antioxidant effects of young apple polyphenols on myofibrillar protein degradation and gelation properties of bighead carp mince during frozen storage

Commercial cryoprotectants can delay quality loss in frozen fish mince, but they are associated with a sweet taste and high calorie content. Young apple polyphenols (YAP), extracted from unripe apples, show potential as an alternative cryoprotectant. This study evaluated the cryoprotective effect of YAP at varying levels (0.3%, 0.7%, and 1%) in unwashed bighead carp mince. The changes in sulfhydryl content, carbonyl content, thiobarbituric acid reactive substances, intrinsic fluorescence intensity, and Fourier transform infrared spectrum indicated that YAP retarded oxidation and structural changes in myofibrillar proteins during the first 8 weeks of frozen storage, as well as lipid oxidation, which protected the structure of myofibrillar protein. At higher concentrations (0.7% and 1%), YAP maintained gel properties, gel springiness, and water-holding capacity of the gel prepared from frozen fish mince, potentially through the promotion of cross-linking of myofibrillar proteins. Overall, YAP can be used as a cryoprotectant and antioxidant in fish mince. PRACTICAL APPLICATION: Our research found that young apple polyphenols have the potential to be an alternative to commercial cryoprotectants. Young apple polyphenols may be used as a sugar-free and healthy cryoprotectant for frozen fish mince production in the future.

Animal and plant-based proteins have different postprandial effects on energy expenditure, glycemia, insulinemia, and lipemia: A review of controlled clinical trials

Dietary proteins have been shown to stimulate thermogenesis, increase satiety, and improve insulin sensitivity in the short and long term. Animal-based proteins (AP) and plant-based proteins (PP) have different amino acid profiles, bioavailability, and digestibility, so it seems to have various short- and long-term effects on metabolic responses. This review aimed to compare the findings of controlled clinical trials on postprandial effects of dietary Aps versus PPs on energy expenditure (EE), lipemia, glycemia, and insulinemia. Data are inconclusive regarding the postprandial effects of APs and PPs. However, there is some evidence indicating that APs increase postprandial EE, DIT, and SO more than PPs. With lipemia and glycemia, most studies showed that APs reduce or delay postprandial glycemia and lipemia and increase insulinemia more than PPs. The difference in amino acid composition, digestion and absorption rate, and gastric emptying rate between APs and PPs explains this difference.

Recent Advances on the Development of Protein-Based Adhesives for Wood Composite Materials-A Review

The industrial market depends intensely on wood-based composites for buildings, furniture, and construction, involving significant developments in wood glues since 80% of wood-based products use adhesives. Although biobased glues have been used for many years, notably proteins, they were replaced by synthetic ones at the beginning of the 20th century, mainly due to their better moisture resistance. Currently, most wood adhesives are based on petroleum-derived products, especially formaldehyde resins commonly used in the particleboard industry due to their high adhesive performance. However, formaldehyde has been subjected to strong regulation, and projections aim for further restrictions within wood-based panels from the European market, due to its harmful emissions. From this perspective, concerns about environmental footprint and the toxicity of these formulations have prompted researchers to re-investigate the utilization of biobased materials to formulate safer alternatives. In this regard, proteins have sparked a new and growing interest in the potential development of industrial adhesives for wood due to their advantages, such as lower toxicity, renewable sourcing, and reduced environmental footprint. This work presents the recent developments in the use of proteins to formulate new wood adhesives. Herein, it includes the historical development of wood adhesives, adhesion mechanism, and the current hotspots and recent progress of potential proteinaceous feedstock resources for adhesive preparation.

High Protein Substitutes for Gluten in Gluten-Free Bread

Gluten-free products have come into the market in order to alleviate health problems such as celiac disease. In this review, recent advances in gluten-free bread are described along with plant-based gluten-free proteins. A comparison with animal-based gluten-free proteins is made reporting on different high protein sources of animal origin. Sea microorganisms- and insect-based proteins are also mentioned, and the optimization of the structure of gluten-free bread with added high protein sources is highlighted along with protein digestibility issues. The latter is an issue for consideration that can be manipulated by a careful design of the mixture in terms of phenolic compounds, soluble carbohydrates and fibres, but also the baking process itself. Additionally, the presence of enzymes and different hydrocolloids are key factors controlling quality features of the final product.

Influence of Plant and Animal Proteins on Inflammation Markers among Adults with Chronic Kidney Disease: A Systematic Review and Meta-Analysis

Proteins, especially plant proteins, may reduce inflammation among adults with chronic kidney disease (CKD). This systematic review and meta-analysis were conducted to evaluate the effect protein types (animal or plant) have on inflammation markers (CRP, IL-6, TNF-α) among adults with varying stages of CKD. The Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) was conducted to identify articles from inception until January 2021, utilizing six databases. Controlled trials that compared the effects of different protein types were analyzed using random-effects meta-analysis. Quality assessment and risk of bias of the included articles were assessed by using Cochrane risk of bias instrument and ROBINS-I. Out of the 10 studies that met the criteria, there was a decreasing trend in CRP levels when consuming plant proteins compared to animal proteins among non-dialysis participants. There was a statistically significant decrease when comparing animal proteins to unspecified proteins in CRP levels among dialysis participants [Hedges’ g = 2.11; 95% CI 1.12, 3.11; p ≤ 0.001], favoring unspecified proteins. Furthermore, animal proteins (eggs, red meat) showed increasing trends in CRP levels compared to whey protein isolate. Caution must be considered regarding these results as controlled, non-randomized, trials were included in the analysis, which may have contributed to high risk of bias. Future research should focus on protein types and the impact they have on kidney disease progression and inflammation markers.

Very-Low-Calorie Ketogenic Diets With Whey, Vegetable, or Animal Protein in Patients With Obesity: A Randomized Pilot Study

CONTEXT

We compared the efficacy, safety, and effect of 45-day isocaloric very-low-calorie ketogenic diets (VLCKDs) incorporating whey, vegetable, or animal protein on the microbiota in patients with obesity and insulin resistance to test the hypothesis that protein source may modulate the response to VLCKD interventions.

SUBJECTS AND METHODS

Forty-eight patients with obesity (19 males and 29 females, homeostatic model assessment (HOMA) index ≥ 2.5, aged 56.2 ± 6.1 years, body mass index [BMI] 35.9 ± 4.1 kg/m2) were randomly assigned to three 45-day isocaloric VLCKD regimens (≤800 kcal/day) containing whey, plant, or animal protein. Anthropometric indexes; blood and urine chemistry, including parameters of kidney, liver, glucose, and lipid metabolism; body composition; muscle strength; and taxonomic composition of the gut microbiome were assessed. Adverse events were also recorded.

RESULTS

Body weight, BMI, blood pressure, waist circumference, HOMA index, insulin, and total and low-density lipoprotein cholesterol decreased in all patients. Patients who consumed whey protein had a more pronounced improvement in muscle strength. The markers of renal function worsened slightly in the animal protein group. A decrease in the relative abundance of Firmicutes and an increase in Bacteroidetes were observed after the consumption of VLCKDs. This pattern was less pronounced in patients consuming animal protein.

CONCLUSIONS

VLCKDs led to significant weight loss and a striking improvement in metabolic parameters over a 45-day period. VLCKDs based on whey or vegetable protein have a safer profile and result in a healthier microbiota composition than those containing animal proteins. VLCKDs incorporating whey protein are more effective in maintaining muscle performance.

Dietary Meat Categories and Descriptions in Chronic Disease Research Are Substantively Different within and between Experimental and Observational Studies: A Systematic Review and Landscape Analysis

This systematic review and landscape analysis describes patterns in dietary meat (skeletal muscle and associated tissues from mammalian, avian, and aquatic species; i.e., muscle foods) categories (CAT) and descriptions (DESCR) used throughout nutrition-related chronic disease literature, as there is anecdotally noted variation. A total of 1020 CAT and 776 DESCR were identified from 369 articles that assessed muscle food consumption and primary prevention of cardiovascular disease, obesity, type 2 diabetes, or cancer in adults ≥19 y from PubMed, Cochrane, and CINAHL up to March 2018. Specificity of CAT was analyzed on an empirical 1-7 ordinal scale as: 1) broad/undescriptive, "fish"; 2) muscle food type, "red meat"; 3) species, "poultry"; 4) broad + 1 descriptor, "processed meat"; 5) type/species + 1 descriptor, "fresh red meat"; 6) broad/type + 2 descriptors, "poached lean fish"; and 7) specific product, "luncheon meat." Median CAT specificity for randomized controlled trials (RCTs) and observational studies (OBSs) was 3 and 2 points out of 7, respectively, with no differences between chronic disease types. Specificity of OBS CAT was higher in recent articles but RCT CAT became less specific starting in the 2000s. RCT CAT were 400% more likely to include species, 500% more likely to include leanness, but 400% less likely to include processing degree compared with OBS CAT. A DESCR was included for 76% and 82% of OBS and RCT CAT, respectively. Researchers described processed meat, red meat, and total meat CAT more commonly than poultry or fish CAT. Among processed meat DESCR, 31% included a common term used in public regulatory definitions. In conclusion, muscle food categories and descriptions are substantively different within and between experimental and observational studies and do not match regulatory definitions. A practical muscle food classification system is warranted to improve interpretation of evidence regarding muscle food consumption and chronic disease.

Amino acid availability of protein meals of different quality for adult and growing mink (Neovison vison)

Protein and amino acid (AA) availability of three protein meals of expected different quality were evaluated in young growing and adult mink. Lamb meal (LM), poultry meal (PM) or fishmeal (FM) were used as main protein sources in three extruded diets investigated by determining apparent total tract digestibility (ATTD) and nitrogen balance in 12 growing mink males aged 8-11 weeks in a Latin square design. In adult mink, ATTD of the diets was determined. The diets had lower protein content than recommended for growing mink, protein contributing 23% of total metabolisable energy (ME), to ensure differences in growth response. The LM diet with expected low protein quality revealed lower content of essential AA than the PM and FM diets. The ATTD of major nutrients and essential AA was significantly affected by diet, with the poorest values for LM, intermediate for PM and the highest values for FM. Mink kits revealed lower ATTD values than adults for protein, AA and especially fat, resulting in lower dietary ME content for kits than for adults. The mean difference was greatest for the LM diet with lowest ATTD and smallest for the FM diet with the highest ATTD. Nitrogen retention and growth rate differed significantly among diets and was lowest for diet LM and highest for diet FM, respectively. Different dietary essential AA contents and ATTD, especially of methionine, were the main factors to explain the difference in growth response. Generally, plasma essential AA concentrations did not clearly reflect the different dietary supply and the different growth response. The study shows that a recommended level of 0.31 g apparent total tract digestible methionine per MJ ME covers the minimum requirement with a safety margin. To obtain optimal growth, the lower digestive capacity in young mink kits should be considered when choosing feed ingredients.

Association between Dietary Patterns of Meat and Fish Consumption with Bone Mineral Density or Fracture Risk: A Systematic Literature

This systematic review aimed to investigate the association of fish and sea fish dietary patterns (FishDiet) and meat or processed meat dietary patterns (MeatDiet) with bone mineral density (BMD) and/or risk of fractures (RF). This review includes 37 studies with a total of 432,924 subjects. The results suggest that MeatDiet and FishDiet did not affect BMD or RF in 48.2% of the subjects with MeatDiet and in 86.5% of the subjects with FishDiet. Positive effects on bone were found in 3% of subjects with MeatDiet and in 12% with FishDiet. Negative effects on bone were observed in 2.7% of FishDiet and in 47.9% of MeatDiet. Major negative effects of MeatDiet were found in subjects located in the Netherlands, Greece, Germany, Italy, Norway, UK and Spain who do not sustain a Mediterranean diet (92.7%); in Korea (27.1%); in Brazil and Mexico (96.4%); and in Australia (62.5%). This study suggests that protein intake from fish or meat is not harmful to bone. Negative effects on bone linked to FishDiet are almost null. Negative effects on bone were associated to MeatDiet in the setting of a Western Diet but not in Mediterranean or Asian Diets.

Dietary protein content for an optimal diet: a clinical view

The dietary protein role in different clinical nutritional conditions and some physio-pathological perspectives is a current and hot topic to discuss. Recent Proceedings of the Protein Summit 2, joining more than 60 nutrition scientists, health experts, and nutrition educators, suggest to increase plant but, in particular, animal protein intake because richer in leucine and consequently more effective to influence anabolic protein metabolism. The Panel conclusions are in apparent contradiction with the nutritional ecology statements, which strongly sustain the reduction of animal origin foods in the human diet and are currently concerned about the excessive, mainly animal protein intake in western and westernized Countries. In conclusion, it is time to carefully evaluate protein and aminoacid intake accurately considering quality, digestibility, daily distribution and individual characteristics.

Protein Supplementation Has Minimal Effects on Muscle Adaptations during Resistance Exercise Training in Young Men: A Double-Blind Randomized Clinical Trial

BACKGROUND

To our knowledge the efficacy of soy-dairy protein blend (PB) supplementation with resistance exercise training (RET) has not been evaluated in a longitudinal study.

OBJECTIVE

Our aim was to determine the effect of PB supplementation during RET on muscle adaptation.

METHODS

In this double-blind randomized clinical trial, healthy young men [18-30 y; BMI (in kg/m(2)): 25 ± 0.5] participated in supervised whole-body RET at 60-80% 1-repetition maximum (1-RM) for 3 d/wk for 12 wk with random assignment to daily receive 22 g PB (n = 23), whey protein (WP) isolate (n = 22), or an isocaloric maltodextrin (carbohydrate) placebo [(MDP) n = 23]. Serum testosterone, muscle strength, thigh muscle thickness (MT), myofiber cross-sectional area (mCSA), and lean body mass (LBM) were assessed before and after 6 and 12 wk of RET.

RESULTS

All treatments increased LBM (P < 0.001). ANCOVA did not identify an overall treatment effect at 12 wk (P = 0.11). There tended to be a greater change in LBM from baseline to 12 wk in the PB group than in the MDP group (0.92 kg; 95% CI: -0.12, 1.95 kg; P = 0.09); however, changes in the WP and MDP groups did not differ. Pooling data from combined PB and WP treatments showed a trend for greater change in LBM from baseline to 12 wk compared with MDP treatment (0.69 kg; 95% CI: -0.08, 1.46 kg; P = 0.08). Muscle strength, mCSA, and MT increased (P < 0.05) similarly for all treatments and were not different (P > 0.10) between treatments. Testosterone was not altered.

CONCLUSIONS

PB supplementation during 3 mo of RET tended to slightly enhance gains in whole-body and arm LBM, but not leg muscle mass, compared with RET without protein supplementation. Although protein supplementation minimally enhanced gains in LBM of healthy young men, there was no enhancement of gains in strength. This trial was registered at clinicaltrials.gov as NCT01749189.

Association of Dietary Protein Consumption With Incident Silent Cerebral Infarcts and Stroke: The Atherosclerosis Risk in Communities (ARIC) Study

BACKGROUND AND PURPOSE

The effect of dietary protein on the risk of stroke has shown inconsistent results. We aimed to evaluate the relationship of dietary protein sources with the risk of stroke and silent cerebral infarcts in a large community-based cohort.

METHODS

We studied 11601 adults (age, 45-64 years at baseline in 1987-1989) enrolled in the Atherosclerosis Risk in Communities (ARIC) Study, free of diabetes mellitus and cardiovascular disease. Dietary protein intake was assessed with validated food frequency questionnaires at baseline and after 6 years of follow-up. Incident stroke events were identified through hospital discharge codes and stroke deaths and physician-adjudicated through December 31, 2011. A subset of participants (n=653) underwent brain magnetic resonance imaging in 1993 to 1995 and in 2004 to 2006. Cox proportional hazard models and logistic regression were used for statistical analyses.

RESULTS

During a median follow-up of 22.7 years, there were 699 stroke events. In multivariable analyses, total, animal, and vegetable protein consumption was not associated with risk of stroke. Red meat consumption was associated with increased stroke risk, particularly ischemic events. The hazard ratios (95% confidence interval) for risk of ischemic stroke across ascending quintiles of red meat consumption were 1 (ref), 1.13 (0.85-1.49), 1.44 (1.09-1.90), 1.33 (0.99-1.79), and 1.47 (1.06-2.05); Ptrend=0.01. No association of major dietary protein sources with silent cerebral infarcts was detected.

CONCLUSIONS

This study supports the notion that consumption of red meat may increase the risk of ischemic stroke. No association between dietary protein intake and silent cerebral infarcts was found.