The Health Benefits of Egg Protein

Once the general public accepts that dietary cholesterol is not a concern for cardiovascular disease risk, foods that have been labeled as high-cholesterol sources, including eggs, may be appreciated for their various other dietary components. One of the nutrients in eggs that deserves further discussion is egg protein. Egg protein has been recognized to be highly digestible and an excellent source of essential amino acids, with the highest attainable protein digestibility-corrected amino acid score. Egg protein has been shown to decrease malnutrition in underdeveloped countries, possibly increase height in children, and protect against kwashiorkor. Egg protein has been demonstrated to be important to skeletal muscle health and protective against sarcopenia. Egg protein also can decrease appetite, resulting in a reduction in the caloric intake from the next meal and weight reduction. Other protective effects of egg protein addressed in this review include protection against infection as well as hypotensive and anti-cancer effects.

Increasing Access to Healthy Foods through Improving Food Environment: A Review of Mixed Methods Intervention Studies with Residents of Low-Income Communities

Food insecurity is a broad and serious public health issue in the United States, where many people are reporting lack of access to healthy foods. The reduced availability of healthy, affordable foods has led to increased consumption of energy-dense and nutrient-poor foods, resulting in increasing the risk for many chronic diseases such as obesity, cardiovascular diseases, and type 2 diabetes mellitus. Thus, identifying promising approaches to increase access to healthy foods through improving the food environment is of importance. The purpose of this review article is to highlight how the food environment affects directly a person’s food choices, and how to increase access to healthy foods through improving environmental approaches. The literature search was focused on finding different approaches to improve food security, primarily those with an impact on food environment. Overall, potential solutions were gathered through multilevel environmental approaches, including nutrition education and peer education, community-based participatory research, and policy changes in supplemental nutrition programs. A recommendation to reduce food insecurity is learning to create meals with a variety of seasonal fruits and vegetables purchased from affordable farmers’ markets.

Fruit juice and childhood obesity: a review of epidemiologic studies

Childhood obesity is a national epidemic, and many efforts have been made to understand its risk factors. The purpose of this review was to provide an updated account of the observational studies evaluating the relationship between 100% fruit juice intake and obesity in children and adolescents, and to highlight the major risk factors that may impact this relationship. PubMed and Scopus were searched for terms related to fruit juice and childhood obesity, and studies assessing 100% fruit juice intake in participants ≤ 19 years old, with obesity-related outcomes (BMI or adiposity), and published before March 9, 2021 were included. There were 17 prospective cohort and 14 cross-sectional studies included in the analysis. Overall, the evidence does not support a relationship between 100% fruit juice intake and measures of obesity in most children. There is some evidence to suggest a minor positive association in some overweight or very young children, but due to fundamental differences and limitations in methodology, further investigation is required. Significant gaps in literature on this topic exist particularly in regards to randomized clinical trials in children, and in studies in racially diverse populations.

Toll-like receptor 4 deficiency promotes the alternative activation of adipose tissue macrophages

Obesity is characterized by adipose tissue (AT) macrophage (ATM) accumulation, which promotes AT inflammation and dysfunction. Toll-like receptor 4 (TLR4) deficiency attenuates AT inflammation in obesity but does not impede the accumulation of ATMs. The purpose of the current study was to determine whether TLR4 deficiency alters ATM polarization. TLR4(-/-) and wild-type mice were fed a low-fat, high-monounsaturated fat (HF(MUFA)), or a high-saturated fat (HF(SFA)) diet for 16 weeks. Further, we used a bone marrow transplant model to determine the influence of hematopoietic cell TLR4 signaling. The metabolic and inflammatory responses to high-fat feeding and ATM phenotype were assessed. Global and hematopoietic cell TLR4 deficiency, irrespective of recipient genotype, produced a shift in ATM phenotype toward an alternatively activated state, which was accompanied by reduced AT inflammation. Despite the observed shift in ATM phenotype, neither global nor hematopoietic cell TLR4 deficiency influenced systemic insulin sensitivity after high-fat feeding. Results of the current study suggest that TLR4 directly influences ATM polarization but question the relevance of TLR4 signaling to systemic glucose homeostasis in obesity.

The role of adipose tissue in mediating the beneficial effects of dietary fish oil

Fish oil improves several features of metabolic syndrome (MetS), such as dyslipidemia, insulin resistance and hepatic steatosis. Fish oil may mediate some of its beneficial effects by modulating the storage and/or secretory functions of adipose tissue (AT). The storage of triglycerides in AT is regulated by the availability of free fatty acids and the degree of lipolysis in AT. Fish oil has been shown to reduce lipolysis in several studies, indicating improved triglyceride storage. Importantly, AT secretes a variety of adipokines and fish oil feeding is associated with remarkable changes in the plasma levels of two key adipokines, adiponectin and leptin. Much attention has been focused on the contribution of adiponectin in fish oil-mediated improvements in MetS. However, emerging evidence also indicates a role of leptin in modulating the components of the MetS upon fish oil feeding. In addition to improving the storage and secretory functions of AT, fish oil, and the n-3 fatty acids found in fish oil, has been shown to reduce inflammation in AT. These effects may be in part a result of activation of peroxisome proliferator-activated receptor γ or inhibition of Toll-like receptor 4. Thus, there is compelling evidence that fish oil mediates its beneficial effects on MetS by improving AT storage and secretory functions and by reducing inflammation.

Limited effect of dietary saturated fat on plasma saturated fat in the context of a low carbohydrate diet

We recently showed that a hypocaloric carbohydrate restricted diet (CRD) had two striking effects: (1) a reduction in plasma saturated fatty acids (SFA) despite higher intake than a low fat diet, and (2) a decrease in inflammation despite a significant increase in arachidonic acid (ARA). Here we extend these findings in 8 weight stable men who were fed two 6-week CRD (12%en carbohydrate) varying in quality of fat. One CRD emphasized SFA (CRD-SFA, 86 g/d SFA) and the other, unsaturated fat (CRD-UFA, 47 g SFA/d). All foods were provided to subjects. Both CRD decreased serum triacylglycerol (TAG) and insulin, and increased LDL-C particle size. The CRD-UFA significantly decreased plasma TAG SFA (27.48 ± 2.89 mol%) compared to baseline (31.06 ± 4.26 mol%). Plasma TAG SFA, however, remained unchanged in the CRD-SFA (33.14 ± 3.49 mol%) despite a doubling in SFA intake. Both CRD significantly reduced plasma palmitoleic acid (16:1n-7) indicating decreased de novo lipogenesis. CRD-SFA significantly increased plasma phospholipid ARA content, while CRD-UFA significantly increased EPA and DHA. Urine 8-iso PGF_2α, a free radical-catalyzed product of ARA, was significantly lower than baseline following CRD-UFA (−32%). There was a significant inverse correlation between changes in urine 8-iso PGF_2α and PL ARA on both CRD (r = −0.82 CRD-SFA; r = −0.62 CRD-UFA). These findings are consistent with the concept that dietary saturated fat is efficiently metabolized in the presence of low carbohydrate, and that a CRD results in better preservation of plasma ARA.

Consuming eggs for breakfast influences plasma glucose and ghrelin, while reducing energy intake during the next 24 hours in adult men

We hypothesized that consuming eggs for breakfast would significantly lower postprandial satiety and energy intake throughout the day. Using a crossover design, 21 men, 20 to 70 years old, consumed 2 isoenergetic test breakfasts, in a random order separated by 1 week. The macronutrient composition of the test breakfasts were as follows: (EGG, % CHO/fat/protein = 22:55:23) and (BAGEL, % CHO/fat/protein = 72:12:16). Fasting blood samples were drawn at baseline before the test breakfast and at 30, 60, 120, and 180 minutes after breakfast. After 180 minutes, subjects were given a buffet lunch and asked to eat until satisfied. Subjects filled out Visual Analog Scales (VAS) during each blood draw and recorded food intake the days before and after the test breakfasts. Plasma glucose, insulin, and appetite hormones were analyzed at each time point. Subjects consumed fewer kilocalories after the EGG breakfast compared with the BAGEL breakfast (P< .01). In addition, subjects consumed more kilocalories in the 24-hour period after the BAGEL compared with the EGG breakfast (P < .05). Based on VAS, subjects were hungrier and less satisfied 3 hours after the BAGEL breakfast compared with the EGG breakfast (P < .01). Participants had higher plasma glucose area under the curve (P < .05) as well as an increased ghrelin and insulin area under the curve with BAGEL (P < .05). These findings suggest that consumption of eggs for breakfast results in less variation of plasma glucose and insulin, a suppressed ghrelin response, and reduced energy intake.

Carbohydrate restriction (with or without additional dietary cholesterol provided by eggs) reduces insulin resistance and plasma leptin without modifying appetite hormones in adult men

Carbohydrate-restricted diets (CRDs) have been shown to reduce body weight, whereas whole egg intake has been associated with increased satiety. The purpose of this study was to evaluate the effects of additional dietary cholesterol and protein provided by whole eggs while following a CRD on insulin resistance and appetite hormones. Using a randomized blind parallel design, subjects were allocated to an egg (640 mg/d additional dietary cholesterol) or placebo (0 mg/d additional dietary cholesterol) group for 12 weeks while following a CRD. There were significant reductions in fasting insulin (P < .025) and fasting leptin concentrations (P < .01) for both groups, which were correlated with the reductions in body weight and body fat (P < .05 and P < .01, respectively). Both groups reduced insulin resistance as measured by the homeostatic model assessment of insulin resistance (P < .025). There was a significant decrease in serum glucose levels observed after the intervention. We did not observe the expected increases in plasma ghrelin levels associated with weight loss, suggesting a mechanism by which subjects do not increase appetite with CRD. To confirm these results, the subjective measures of satiety using visual analog scale showed that both groups felt more "full" (P < .05), "satisfied" (P < .001), and "wanted to eat less" (P < .001) after the intervention. These results indicate that inclusion of eggs in the diet (additional dietary cholesterol) did not modify the multiple beneficial effects of CRD on insulin resistance and appetite hormones.

Impact of increased adipose tissue mass on inflammation, insulin resistance, and dyslipidemia

Obesity is associated with increased prevalence of metabolic disorders, such as inflammation, insulin resistance, and dyslipidemia, which can predispose an individual to develop diabetes and cardiovascular disease. Adipose tissue (AT) is now recognized as a metabolically active organ that controls plasma free fatty acid levels and contributes to systemic metabolic homeostasis by secreting adipokines. In obesity, the recruitment of immune cells, such as T cells and macrophages, to AT causes inflammation, which is thought to contribute to local insulin resistance. This loss of insulin sensitivity within AT can lead to uncontrolled release of fatty acids, secretion of inflammatory cytokines, and alterations in the balance of adipokines, which ultimately impact lipoprotein metabolism and insulin sensitivity systemically. Thus, AT itself plays an important role in the increased risk of diabetes and cardiovascular disease that is associated with obesity.

Impact of macrophage toll-like receptor 4 deficiency on macrophage infiltration into adipose tissue and the artery wall in mice

AIMS/HYPOTHESIS

Toll-like receptor 4 (TLR4) is a receptor for saturated fatty acids (SFAs), global deficiency of which has been shown to protect against inflammation, insulin resistance and atherosclerotic lesion formation. Because macrophages express Tlr4 and are important in insulin resistance and atherosclerotic lesion formation due to their infiltration of white adipose tissue (WAT) and the artery wall, respectively, we hypothesised that deficiency of macrophage TLR4 could protect against these disorders.

METHODS

Bone marrow transplantation of agouti, LDL-receptor deficient (A(y)/a; Ldlr (-/-)) mice with marrow from either C57BL/6 or Tlr4 (-/-) mice was performed. Recipient mice with Tlr4 (+/+) marrow (MthetaTLR4(+/+)) or with Tlr4 (-/-) marrow (MthetaTLR4(-/-)) were then placed on one of four diets: (1) low fat; (2) high fat; (3) high fat rich in SFAs (HF(SFA)); and (4) HF(SFA) supplemented with fish oil.

RESULTS

There were no differences in body composition or plasma lipids between MthetaTLR4(+/+) and MthetaTLR4(-/-) mice on any of the diets. However, we observed a decrease in some macrophage and inflammatory markers in WAT of female low fat-fed MthetaTLR4(-/-) mice compared with MthetaTLR4(+/+) mice. MthetaTLR4(-/-) mice fed low-fat diet also displayed decreased atherosclerotic lesion area. There were no differences in macrophage accrual in WAT or atherosclerosis between MthetaTLR4(+/+) and MthetaTLR4(-/-) mice fed any of the high-fat diets. Finally, no difference was seen in insulin sensitivity between MthetaTLR4(+/+) and MthetaTLR4(-/-) mice fed the HF(SFA) diet.

CONCLUSIONS/INTERPRETATION

These data suggest that under certain dietary conditions, macrophage expression of Tlr4 can be an important mediator of macrophage accumulation in WAT and the artery wall.

Raisins and walking alter appetite hormones and plasma lipids by modifications in lipoprotein metabolism and up-regulation of the low-density lipoprotein receptor

The purpose of this study was to determine the effects of consuming raisins, increasing steps walked, or a combination of these interventions on lipoprotein metabolism and appetite hormones by assessing plasma apolipoprotein concentrations, cholesterol ester transfer protein activity, low-density lipoprotein (LDL) receptor messenger RNA (mRNA) abundance, and plasma ghrelin and leptin concentrations. Thirty-four subjects (17 men and 17 postmenopausal women) were matched for weight and sex and randomly assigned to consume 1 cup raisins per day (RAISIN), increase the amount of steps walked per day (WALK), or a combination of both interventions (RAISIN + WALK). The subjects completed a 2-week run-in period, followed by a 6-week intervention. Ribonucleic acid was extracted from mononuclear cells, and LDL receptor mRNA abundance was quantified by use of reverse transcriptase polymerase chain reaction. Plasma apolipoproteins were measured by Luminex (Austin, TX) technology. Apoproteins A-1, B, C-II, and E and cholesterol ester transfer protein activity were not altered for any of the groups. In contrast, apolipoprotein C-III was significantly decreased by 12.3% only in the WALK group (P < .05). Low-density lipoprotein receptor mRNA abundance was increased for all groups after the intervention (P < .001). There was a significant group effect for plasma leptin (P = .026). Plasma concentrations increased for RAISIN and RAISIN + WALK. Similarly, plasma ghrelin concentrations were elevated postintervention for both groups consuming raisins (P < .05). These data suggest that walking and raisin consumption decrease plasma LDL cholesterol by up-regulating the LDL receptor and that raisin consumption may reduce hunger and affect dietary intake by altering hormones influencing satiety.

Carbohydrate restriction has a more favorable impact on the metabolic syndrome than a low fat diet

We recently proposed that the biological markers improved by carbohydrate restriction were precisely those that define the metabolic syndrome (MetS), and that the common thread was regulation of insulin as a control element. We specifically tested the idea with a 12-week study comparing two hypocaloric diets (approximately 1,500 kcal): a carbohydrate-restricted diet (CRD) (%carbohydrate:fat:protein = 12:59:28) and a low-fat diet (LFD) (56:24:20) in 40 subjects with atherogenic dyslipidemia. Both interventions led to improvements in several metabolic markers, but subjects following the CRD had consistently reduced glucose (-12%) and insulin (-50%) concentrations, insulin sensitivity (-55%), weight loss (-10%), decreased adiposity (-14%), and more favorable triacylglycerol (TAG) (-51%), HDL-C (13%) and total cholesterol/HDL-C ratio (-14%) responses. In addition to these markers for MetS, the CRD subjects showed more favorable responses to alternative indicators of cardiovascular risk: postprandial lipemia (-47%), the Apo B/Apo A-1 ratio (-16%), and LDL particle distribution. Despite a threefold higher intake of dietary saturated fat during the CRD, saturated fatty acids in TAG and cholesteryl ester were significantly decreased, as was palmitoleic acid (16:1n-7), an endogenous marker of lipogenesis, compared to subjects consuming the LFD. Serum retinol binding protein 4 has been linked to insulin-resistant states, and only the CRD decreased this marker (-20%). The findings provide support for unifying the disparate markers of MetS and for the proposed intimate connection with dietary carbohydrate. The results support the use of dietary carbohydrate restriction as an effective approach to improve features of MetS and cardiovascular risk.

Modulation of C-reactive protein, tumor necrosis factor-alpha, and adiponectin by diet, exercise, and weight loss

Chronic disease has been strongly correlated with inflammation resulting from the body's release of inflammatory cytokines as a result of injury or infection. Specific interventions promoting weight loss, exercise, or intake of antioxidants have been used by several investigators in an effort to decrease inflammatory cytokines. C-reactive protein (CRP) is produced by the liver and its role in the development of inflammation has been well established. However, the strong association between CRP and risk for heart disease is a more recent discovery. During the inflammation process, the transcriptional activity of nuclear factor kappaB leads to the increased production of inflammatory cytokines associated with atherosclerosis, including tumor necrosis factor-alpha (TNFalpha). Increased concentrations of TNFalpha have been reported in obese patients; thus, weight loss is considered a key intervention to reduce the concentrations of this cytokine. In contrast to CRP and TNFalpha, adiponectin increases during weight loss and insulin sensitivity. Additionally, lower concentrations of this cytokine have been reported in cardiovascular disease and type-2 diabetes. Recent epidemiological studies and clinical interventions have reported contradictory findings related to dietary or exercise interventions and the resulting alterations in plasma cytokines. Part of the discrepancies may be due to the population studied, the time of the treatment, and the lack of weight loss in some studies. Although it is clear from the literature that these cytokines play a major role in the development of chronic disease, the best strategy to favorably alter the inflammatory response is still debatable.

Raisins and additional walking have distinct effects on plasma lipids and inflammatory cytokines

Background

Raisins are a significant source of dietary fiber and polyphenols, which may reduce cardiovascular disease (CVD) risk by affecting lipoprotein metabolism and inflammation. Walking represents a low intensity exercise intervention that may also reduce CVD risk. The purpose of this study was to determine the effects of consuming raisins, increasing steps walked, or a combination of these interventions on blood pressure, plasma lipids, glucose, insulin and inflammatory cytokines.

Results

Thirty-four men and postmenopausal women were matched for weight and gender and randomly assigned to consume 1 cup raisins/d (RAISIN), increase the amount of steps walked/d (WALK) or a combination of both interventions (RAISINS + WALK). The subjects completed a 2 wk run-in period, followed by a 6 wk intervention. Systolic blood pressure was reduced for all subjects (P = 0.008). Plasma total cholesterol was decreased by 9.4% for all subjects (P < 0.005), which was explained by a 13.7% reduction in plasma LDL cholesterol (LDL-C) (P < 0.001). Plasma triglycerides (TG) concentrations were decreased by 19.5% for WALK (P < 0.05 for group effect). Plasma TNF-α was decreased from 3.5 ng/L to 2.1 ng/L for RAISIN (P < 0.025 for time and group × time effect). All subjects had a reduction in plasma sICAM-1 (P < 0.01).

Conclusion

This research shows that simple lifestyle modifications such as adding raisins to the diet or increasing steps walked have distinct beneficial effects on CVD risk.

Eggs modulate the inflammatory response to carbohydrate restricted diets in overweight men

Background

Carbohydrate restricted diets (CRD) consistently lower glucose and insulin levels and improve atherogenic dyslipidemia [decreasing triglycerides and increasing HDL cholesterol (HDL-C)]. We have previously shown that male subjects following a CRD experienced significant increases in HDL-C only if they were consuming a higher intake of cholesterol provided by eggs compared to those individuals who were taking lower concentrations of dietary cholesterol. Here, as a follow up of our previous study, we examined the effects of eggs (a source of both dietary cholesterol and lutein) on adiponectin, a marker of insulin sensitivity, and on inflammatory markers in the context of a CRD.

Methods

Twenty eight overweight men [body mass index (BMI) 26–37 kg/m²] aged 40–70 y consumed an ad libitum CRD (% energy from CHO:fat:protein = 17:57:26) for 12 wk. Subjects were matched by age and BMI and randomly assigned to consume eggs (EGG, n = 15) (640 mg additional cholesterol/day provided by eggs) or placebo (SUB, n = 13) (no additional dietary cholesterol). Fasting blood samples were drawn before and after the intervention to assess plasma lipids, insulin, adiponectin and markers of inflammation including C-reactive protein (CRP), tumor necrosis factor-alpha (TNF-α), interleukin-8 (IL-8), monocyte chemoattractant protein-1 (MCP-1), intercellular adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule-1(VCAM-1).

Results

Body weight, percent total body fat and trunk fat were reduced for all subjects after 12 wk (P < 0.0001). Increases in adiponectin were also observed (P < 0.01). Subjects in the EGG group had a 21% increase in this adipokine compared to a 7% increase in the SUB group (P < 0.05). Plasma CRP was significantly decreased only in the EGG group (P < 0.05). MCP-1 levels were decreased for the SUB group (P < 0.001), but unchanged in the EGG group. VCAM-1, ICAM-1, TNF-α, and IL-8 were not modified by CRD or eggs.

Conclusion

A CRD with daily intake of eggs decreased plasma CRP and increased plasma adiponectin compared to a CRD without eggs. These findings indicate that eggs make a significant contribution to the anti-inflammatory effects of CRD, possibly due to the presence of cholesterol, which increases HDL-C and to the antioxidant lutein which modulates certain inflammatory responses.

Effect of Post-Exercise Supplement Consumption on Adaptations to Resistance Training

OBJECTIVE

Athletes are interested in nutritional manipulations that may enhance lean tissue gains stimulated by resistance training. Some research demonstrates that acute consumption of food containing protein causes superior muscle protein synthesis compared to isoenergetic foods without protein. This benefit has not been verified in longer-term training studies. We compared body composition and muscle function responses to resistance training in males who consumed a carbohydrate or a multi-macronutrient beverage following each training session.

METHODS

Nineteen, untrained men (18-25 years) consumed either a milk (MILK) or a carbohydrate-electrolyte (CHO) drink immediately following each workout during a 10 week resistance training program. Muscle strength (1RM for seven exercises), body composition (DXA scan), fasted, resting concentrations of serum total and free testosterone, cortisol, IGF-1, and resting energy expenditure (REE) were measured prior to and at the end of training.

RESULTS

Resistance training caused an increase (44 +/- 4%, p < 0.001) in muscular strength for all subjects. The training program reduced percent body fat (8%, p < 0.05, -0.9 +/- 0.5 kg) and increased fat-free soft tissue (FFST) mass (2%, 1.2 +/- 0.3 kg, p < 0.01). MILK tended to increase body weight and FFST mass (p = 0.10 and p = 0.13, respectively) compared to CHO. Resting total and free testosterone concentrations decreased from baseline values in all subjects (16.7%, 11%, respectively, p < 0.05). Significant changes in fasting IGF-1, cortisol, and REE across training were not observed for either group.

CONCLUSION

Post-resistance exercise consumption of MILK and CHO caused similar adaptations to resistance training. It is possible that a more prolonged training with supplementation period would expand the trend for greater FFST gains in MILK.