High Density Lipoprotein from Egg Yolk (EYHDL) Improves Dyslipidemia by Mediating Fatty Acids Metabolism in High Fat Diet-induced Obese Mice

Constructing myosin/high-density lipoprotein composite emulsions: Roles of pH on emulsification stability, rheological and structural properties

The emulsification activity of myosin plays a significant role in affecting quality of emulsified meat products. High-density lipoprotein (HDL) possesses strong emulsification activity and stability due to its structural characteristics, suggesting potential for its utilization in developing functional emulsified meat products. In order to explore the effect of HDL addition on emulsification stability, rheological properties and structural features of myosin (MS) emulsions, HDL-MS emulsion was prepared by mixing soybean oil with isolated HDL and MS, with pH adjustments ranging from 3.0 to 11.0. The results found that emulsification activity and stability in two emulsion groups consistently improved as pH increased. Under identical pH, HDL-MS emulsion exhibited superior emulsification behavior as compared to MS emulsion. The HDL-MS emulsion under pH of 7.0-11.0 formed a viscoelastic protein layer at the interface, adsorbing more proteins and retarding oil droplet diffusion, leading to enhanced oxidative stability, compared to the MS emulsion. Raman spectroscopy analysis showed more flexible conformational changes in the HDL-MS emulsion. Microstructural observations corroborated these findings, showing a more uniform distribution of droplet sizes in the HDL-MS emulsion with smaller particle sizes. Overall, these determinations suggested that the addition of HDL enhanced the emulsification behavior of MS emulsions, and the composite emulsions demonstrated heightened responsiveness under alkaline conditions. This establishes a theoretical basis for the practical utilization of HDL in emulsified meat products.

Optimizing the formation of myosin/high-density lipoprotein composite gels: PH-dependent effects on heat-induced aggregation

This study investigated impact of high-density lipoprotein (HDL) on thermal aggregation and gelling behavior of myosin in relation to varied pHs. Results revealed that HDL modified myosin structure before and after heating, with distinct effects observed at varied pH. Under pH 5.0, both myosin and HDL-MS exhibited larger aggregates and altered microstructure; at pH 7.0 and 9.0, HDL inhibited myosin aggregation, resulting in enhanced solubility, reduced turbidity and particle size. Comparative analysis of surface hydrophobicity, free sulfhydryl groups and secondary structure highlighted distinct thermal aggregation behavior between MS and HDL-MS, with the latter showing inhibitory effects under neutral or alkaline conditions. Gelation behavior was enhanced at pH 7.0 with maximum strength, hardness, water-holding capacity and rheological properties. Under acidic pH, excessive protein aggregation resulted in increased whiteness and rough microstructure with granular aggregates. Under alkaline pH, gel network structure was weaker, possibly due to higher thermal stability of protein molecules. Scanning electron microscopy revealed expanded HDL protein particles at pH 7.0, accounting for decreased gel strength and altered rheological properties compared with myosin gel. Overall, the results indicated a positive role of HDL at varied pH in regulating thermal aggregation of myosin and further impacting heat-induced gel characteristics.

Ameliorative effect of ethanolic extract of Carica papaya leaves on hyper-cholesterolemic rats: The egg yolk induced model

Cardiovascular disease is one of the leading killers in the world today, and hyperlipidemia is one of the main risk factors. The prevalence of hyperlipidemia is rising dramatically worldwide and is mostly felt in poorer nations. The majority of communities and individuals in Africa are known to turn to ethnomedicine for their medical requirements. The tropical plant Carica papaya, which is grown for its edible, ripe fruit in Africa, was used in folk medicine for treatment of cardiovascular issues as well as a number of serious illnesses. This study assessed the anticholesterolemic property of the ethanolic extracts of Carica papaya leaves, adapting the egg yolk-induced hyperlipidaemia model in Wistar albino rats. This study prepared egg yolk to induce hyperlipidaemia in the Wistar rats, then treated some groups with the extract of Carica papaya leaves, and other groups with the standard drug Fenofibrate. The Wistar rats in the control group were given 2% acacia instead of egg yolk. The total cholesterol, triglycerides, as well as biological and haematological parameters, were determined. The Carica papaya leaves extracts significantly (p<0.05) decreased the total cholesterol and LDL cholesterol levels at all doses administered, but the extract and the standard drug had no significant effect on HDL cholesterol. An inverse relationship between the Carica papaya leaves extract doses and the cholesterol levels was observed placing the efficacy in the order of 100 mg/kg > 250 mg/kg > Fenofibrate (2.29 mg/kg) > 500 mg/kg. With the potential efficacy of Carica papaya leaves extract in the treatment of hypercholesterolemia and, as a result, cardiovascular diseases, more research on bioactive molecule isolation/characterisation for pharmaceutical use or incorporation into functional food products for CVD management is required.

Effect of Modified-Hen-Egg-Yolk-Lipid-Composition Diet on Plasma Lipids in Rats

This study aimed to investigate the effects of dietary supplementation with modified-hen-egg-yolk on plasma lipids and lipoprotein profiles in rats. During the four-week-experiment, 64 Wistar rats were divided into four groups of 16 (eight of both sexes), and fed commercial rat food (group C); food containing 70% commercial rat mixture and 30% freshly cooked egg yolk originating from laying hen eggs fed with 3% fish oil (group F); 3% palm olein (group P), or 3% lard (group L). The cooked egg yolk in the rat diet affected the concentrations of plasma total and LDL-cholesterol in males of the P and L groups. Cholesterol and total fat in the diet did not have a hypercholesterolemic effect on their own, but when in combination with fatty acid composition, they could contribute to an increase in plasma total and LDL cholesterol concentrations in rats. HDL-cholesterol was the most resilient plasma lipoprotein of rats to dietary treatments in our experiment. Compared to the control group, the addition of hen egg yolk to the rat diet regardless of its quality, adversely affected the values of HDL-C/TC and HDL-C/LDL-C in both males and females.

Novel extraction technologies and potential applications of egg yolk proteins

The high nutritional value and diverse functional properties of egg yolk proteins have led to its widespread use in the fields of food, medicine, and cosmetics. Various extraction methods have been reported to obtain the proteins from egg yolk, however, their utilization is limited due to the relatively low extraction efficiency and/or toxic solvents involved. Several simpler and greener technologies, especially physical fields (ultrasound), have been successfully developed to improve the extraction efficiency. The egg yolk proteins may exert multiple biological activities, enabling them to be a promising tool in improve human health and wellbeing, such as anti-obesity, anti-atherosclerosis, anti-osteoporosis, diagnosis and therapy for SARS-CoV-2 infections. This article summarizes the novel extraction technologies and latest applications of the egg yolk proteins in the recent 5 years, which should stimulate their utilization as health-promoting functional ingredients in foods and other commercial products.

Dietary Phytogenic Extracts Favorably Influence Productivity, Egg Quality, Blood Constituents, Antioxidant and Immunological Parameters of Laying Hens: A Meta-Analysis

The present study aimed to assess the impact of dietary phytogenic extracts on laying hen productivity, egg quality, blood constituents, antioxidant, and immunological parameters through a meta-analytical approach. A total of 28 articles (119 data points) reporting the influence of dietary phytogenic extracts on the productive performance, egg quality, blood constituents, immunological, and antioxidant parameters of laying hens were embedded into a database. Statistical analysis was performed using a mixed model, with different studies treated as random effects and phytogenic extract levels treated as fixed effects. This meta-analysis revealed that dietary phytogenic extracts quadratically (p < 0.05) improved egg production and egg mass as well as decreased (p < 0.05) the feed conversion ratio (FCR) with no adverse effect on egg weight and egg quality. Feed intake and egg yolk percentage tended to increase linearly (p < 0.1). Total serum cholesterol and low-density lipoprotein (LDL) declined quadratically (p < 0.001 and p < 0.05, respectively), high-density lipoprotein (HDL) increased linearly (p < 0.001), and malondialdehyde (MDA) decreased linearly (p < 0.01), with increasing levels of dietary phytogenic extract. In addition, immunoglobulin G (IgG), immunoglobulin A (IgA), glutathione peroxidase (GSH-Px), and total superoxide dismutase (TSOD) increased linearly (p < 0.05) in line with the increase in dietary phytogenic extract level. It was concluded that the inclusion of phytogenic extracts in the diet of laying hens had a positive effect on productive performance, feed efficiency, egg mass, immunity, and antioxidant activity without interfering with egg quality. The optimum level of feed photogenic extract for egg production and feed efficiency was determined to be around 300 mg/kg feed.

Relationship between Egg Consumption and Metabolic Syndrome. A Meta-Analysis of Observational Studies

OBJECTIVES

Aims: To explore the association between egg consumption and metabolic syndrome (MetS) in the adult population.

METHODS

The PubMed, Web of Science and Embase electronic databases were searched up to December 2021 for observational studies on the association between egg consumption and MetS in the adult population. The pooled relative risk (RR) of MetS for the highest versus lowest category of egg consumption, and the standard mean difference (SMD) of egg consumption for MetS versus control subjects were calculated. Egg consumption was assessed by a food-frequency questionnaire (FFQ) and the 24-hour recall method. The criteria for MetS were National Cholesterol Education Program-Adult Treatment Panel III (NCEP ATP III), International Diabetes Federation (IDF), Joint Interim Statement (JIS) and American Heart Association (AHA).

RESULTS

A total of 19 articles with 20 observational studies (331667 participants) were included in this meta-analysis. The overall multivariable adjusted RR (18 studies included) demonstrated that higher egg consumption was associated with a lower probability of having MetS (RR=0.92, 95%CI: 0.88 to 0.96; P<0.001). Subgroup analysis confirmed these findings in cross-sectional studies (RR=0.91, 95% CI: 0.88 to 0.95; P<0.001), studies that used the NCEP ATP III criteria (RR=0.94, 95% CI: 0.89 to 0.99; P=0.02), Asia (RR=0.92, 95% CI: 0.86 to 0.99; P=0.02), studies with samples sizes >5000 (RR=0.92, 95% CI: 0.86 to 0.96; P<0.001), studies that adjusted body mass index (BMI) (RR=0.90, 95% CI: 0.86 to 0.95; P<0.001) and energy intake (RR=0.89, 95% CI: 0.83 to 0.94; P<0.001) and high-quality studies (RR=0.91, 95% CI: 0.88 to 0.95; P<0.001). Moreover, the overall combined SMD (5 studies included) showed that the level of egg consumption in subjects with MetS was also lower than that in control subjects. (SMD=-0.22, 95% CI: -0.25 to -0.20; P<0.001). Sensitivity analysis demonstrated that this finding only existed in studies with samples sizes >5000 (SMD=-0.21, 95% CI: -0.29 to -0.12; P<0.001) and high-quality studies (SMD=-0.23, 95% CI: -0.26 to -0.20; P<0.001).

CONCLUSION

Our results suggest that higher egg consumption is associated with a lower probability of having MetS in the adult population. However, due to the limited evidence, more global well-designed prospective cohort studies are still needed.

Lactobacillus fermentum SMFM2017-NK4 Isolated from Kimchi Can Prevent Obesity by Inhibiting Fat Accumulation

This study evaluated the anti-obesity effects of lactic acid bacteria. Thirty-one lactic acid bacteria were examined in vitro for their ability to inhibit α-glucosidase activity, lipase activity, and 3T3-L1 cell differentiation. Four selected lactic acid bacteria were administered to obese C57BL/6J mice models for 8 weeks. The degree of improvement in obesity was determined by weight gain and serum biochemical analysis. The expression levels of genes (Fas and Cpt-2) related to obesity in the liver were analyzed by quantitative reverse transcription (qRT)-PCR. In addition, antioxidant protein levels (SOD-2, CAT, and GPx-1) in the liver were evaluated. The lactic acid bacteria-treated groups (PPGK1, LFNK3, LPNK2, and LFNK4) showed lower weight increase rate than the control group. The total cholesterol (T-chol), triglyceride (TG), alanine aminotransferase (ALT), and aspartate aminotransferase (AST) levels in the blood serum of the LFNK4 group were the lowest among other groups, compared to the control group. The expression levels of lipid metabolism-related genes (Fas and Cpt-2) in the liver of the LFNK4 group were lower in Fas and higher in Cpt-2 than in the control group. The antioxidant protein expression levels (SOD-2, CAT, and GPx-1) in the liver tissue were also higher in the LFNK4 group. These results indicate that L. fermentum SMFM2017-NK4 has anti-obesity effects.

Dietary lipids and cardiometabolic health: a new vision of structure-activity relationship

PURPOSE OF REVIEW

The impact of dietary lipids on cardiometabolic health was mainly studied considering their fatty acid composition. This review aims to present the recent change in paradigm whereby the food matrix, the molecular and supramolecular structures of dietary lipids modulate their digestive fate and cardiometabolic impact.

RECENT FINDINGS

Epidemiological studies have reported that the metabolic impact of full-fat dairy products is better than predictable upon saturated fatty acid richness. Milk polar lipid supplementation reduced adiposity and inflammation in rodents by modulating gut microbiota and barrier, and decreased lipid markers of cardiovascular disease risk in humans by lowering cholesterol absorption. The metabolic importance of the structure of lipid molecules carrying omega-3 (molecular carrier) has also been documented. Plant lipids exhibit specific assemblies, membrane and molecular structures with potential health benefits. Lipid emulsifiers used to stabilize fats in processed foods are not mere bystanders of lipid effects and can induce both beneficial and adverse health effects.

SUMMARY

These findings open new clinical research questions aiming to further characterize the cardiometabolic fate of lipids, from digestion to bioactive metabolites, according to the food source or molecular carrier. This should be useful to elaborate food formulations for target populations and personalized dietary recommendations.

Whole Egg Consumption Decreases Cumulative Weight Gain in Diet-Induced Obese Rats

BACKGROUND

Whole egg (WE) consumption has been demonstrated to attenuate body weight (BW) gain and adiposity in genetic animal models of type 2 diabetes (T2D). This finding was accompanied by increased food consumption.

OBJECTIVES

This study aimed to examine the effects of long-term WE intake on BW gain, fat distribution, and food intake in a rat model of diet-induced obesity (DIO).

METHODS

Male Sprague Dawley rats (n = 24) were obtained at 5 wk of age and were randomly weight-matched across 1 of 4 dietary intervention groups (6 rats per group): a casein-based diet (CAS), a high-fat high-sucrose CAS diet (HFHS CAS), a whole egg-based diet (EGG), or a high-fat high-sucrose EGG diet (HFHS EGG). All diets provided 20% (w/w) protein and were provided for 33 wk. HFHS diets provided ∼61% of kilocalories from fat and 10% from sucrose. Daily weight gain and food intake were recorded, biochemical parameters were measured via ELISA, and epididymal fat pad weights were recorded at the end of the study.

RESULTS

At 33 wk, cumulative BW gain in DIO rats fed HFHS EGG resulted in 23% lower weight gain compared with DIO rats fed HFHS CAS (P < 0.0001), but no significant differences in BW gain were observed between the HFHS EGG group and the control EGG and CAS groups (P = 0.71 and P = 0.61, respectively). Relative food intake (grams per kilogram BW) was 23% lower (P < 0.0001) in rats fed HFHS CAS compared with CAS, whereas there was no difference in food intake within the EGG dietary groups. DIO rats fed HFHS EGG exhibited a 22% decrease in epididymal fat weight compared with their counterparts fed the HFHS CAS.

CONCLUSIONS

Our data demonstrate that consumption of a WE-based diet reduced BW gain and visceral fat in the DIO rat, similar to our previous findings in a genetic rat model with T2D.

Akkermansia muciniphila Prevents Fatty Liver Disease, Decreases Serum Triglycerides, and Maintains Gut Homeostasis

The objective of this study was to elucidate the effect of intestinal Akkermansia muciniphila bacteria on fatty liver disease. Five-week-old C57BL/6N mice were administered either phosphate-buffered saline (PBS; control) or A. muciniphila at 10⁸ to 10⁹ CFU/ml, and were fed either a 45% fat diet (high-fat diet [HFD]) or a 10% fat diet (normal diet [ND]) for 10 weeks. After 10 weeks, the mice were euthanized, and blood and tissue samples, including adipose tissue, cecum, liver, and brain, were immediately collected. Biochemical and histological analyses were conducted, and the expression levels of related factors were compared to determine the antiobesity effects of Akkermansia muciniphila The gut microbiome was analyzed in fecal samples. Oral administration of A. muciniphila significantly (P < 0.05) lowered serum triglyceride (TG) and alanine aminotransferase (ALT) levels in obese mice. Compared to the non-A. muciniphila-treated group, the expression of SREBP (regulator of TG synthesis in liver tissue) was decreased in the A. muciniphila-treated group. The expression of IL-6 in the liver of obese mice was decreased following the administration of A. muciniphila Furthermore, alterations in the ratio of Firmicutes to Bacteroidetes and the decrease in bacterial diversity caused by the HFD were restored upon the administration of A. muciniphila These results indicate that A. muciniphila prevents fatty liver disease in obese mice by regulating TG synthesis in the liver and maintaining gut homeostasis.IMPORTANCE This study investigated the effect of Akkermansia muciniphila on fatty liver disease. Although some research about the effects of A. muciniphila on host health has been published, study of the relationship between A. muciniphila administration and fatty liver, as well as changes in the gut microbiota, has not been conducted. In this study, we demonstrated that A. muciniphila prevented fatty liver disease by regulation of the expression of genes that regulate fat synthesis and inflammation in the liver.

Biological Activities of Egg Yolk Lipids: A Review

As one of six dietary nutrients, lipid derived from different food matrices has been extensively studied and has an appropriate application in food, medicine, and cosmetic industry. Egg is a richly nutritive food, of which proteins and lipids possess excellent functional characteristics and biological activities. In recent years, egg yolk lipid has been successively separated and investigated, such as egg yolk oil, phospholipids, and fatty acids, which have anti-inflammatory activity, antioxidant activity, cardiovascular protection, and memory improvement, involving the regulation of cell function and physiological homeostatic balance. In this paper, the biological activities and underlying benefit of egg yolk lipids and fat-soluble components have been highlighted and summarized. Meanwhile, the quantitative data of egg yolk lipids needed to achieve any of the described biological effects and recommended concentrations relevant for dietary intake are reviewed. Finally, current challenges and crucial issues of high-efficiency utilization of egg yolk lipids are also discussed.