Catherine J. Andersen

Whole egg consumption improves lipoprotein profiles and insulin sensitivity to a greater extent than yolk-free egg substitute in individuals with metabolic syndrome

OBJECTIVE We investigated if daily egg feeding, along with carbohydrate restriction, would alter lipoprotein metabolism and influence atherogenic lipoprotein profiles and insulin resistance in men and women with metabolic syndrome (MetS). METHODS In a randomized, single-blind, parallel design, participants consumed either 3 whole eggs/day (EGG, n=20) or the equivalent amount of yolk-free egg substitute (SUB, n=17), as part of a moderately carbohydrate-restricted diet (25%-30% energy) for 12 weeks. Plasma lipids, apolipoproteins (apos), oxidized LDL (oxLDL), cholesteryl ester transfer protein (CETP) and lecithin-cholesterol acyltransferase (LCAT) activities were assessed at baseline and week 12. Lipoprotein particle concentrations and sizes were measured by nuclear magnetic resonance spectroscopy. RESULTS Atherogenic dyslipidemia improved for all individuals as evidenced by reductions in plasma triglycerides, apoC-III, apoE, oxLDL, VLDL particle diameter, large VDL, total IDL, small LDL, and medium LDL particles (P<0.05). Furthermore, there were increases in HDL-cholesterol, large LDL and large HDL particles (P<0.05) for all individuals. However, there were greater increases in HDL-cholesterol and large HDL particles, and reductions in total VLDL and medium VLDL particles for those consuming EGG compared to SUB (P<0.05). Plasma insulin and insulin resistance (HOMA-IR) were reduced, while LCAT activity, and both HDL and LDL diameters increased over time in the EGG group only (P<0.05). CONCLUSIONS Incorporating daily whole egg intake into a moderately carbohydrate-restricted diet provides further improvements in the atherogenic lipoprotein profile and in insulin resistance in individuals with MetS.

A Mediterranean-style, low-glycemic-load diet decreases atherogenic lipoproteins and reduces lipoprotein (a) and oxidized low-density lipoprotein in women with metabolic syndrome

The objective was to assess the impact of a Mediterranean-style, low-glycemic-load diet (control group, n = 41) and the same diet plus a medical food (MF) containing phytosterols, soy protein, and extracts from hops and Acacia (MF group, n = 42) on lipoprotein atherogenicity in women with metabolic syndrome. Plasma lipids, apolipoproteins (apos), lipoprotein subfractions and particle size, low-density lipoprotein (LDL) oxidation, and lipoprotein (a) were measured at baseline, week 8, and week 12 of the intervention. Three-day dietary records were collected at the same time points to assess compliance. Compared with baseline, women decreased energy intake from carbohydrate (P < .001) and fat (P < .001), whereas they increased energy intake from protein (P < .001). A significant increase in energy from monounsaturated fatty acids was also observed as well as increases in eicosapentaenoic acid and docosahexaenoic acid, whereas trans-fatty acid intake was reduced (P < .00001). The atherogenic lipoproteins, large very low-density lipoprotein (P < .0001) and small LDL (P < .0001), were reduced, whereas the ratio of large high-density lipoprotein to smaller high-density lipoprotein particles was increased (P < .0001). Apolipoprotein B was reduced for all women (P < .0001), with a greater reduction in the MF group (P < .025). Oxidized LDL (P < .05) and lipoprotein (a) (P < .001) were reduced in both groups at the end of the intervention. Consumption of a Mediterranean-style diet reduces the risk for cardiovascular disease by decreasing atherogenic lipoproteins, oxidized LDL, and apo B. Inclusion of an MF may have an additional effect in reducing apo B.

Effects of carbohydrate restriction and dietary cholesterol provided by eggs on clinical risk factors in metabolic syndrome

BACKGROUND There are a limited number of clinical interventions evaluating the effects of dietary cholesterol in individuals at elevated risk for type 2 diabetes and cardiovascular disease. OBJECTIVE To investigate the effects of whole egg intake in adults with metabolic syndrome (MetS). METHODS Men (n = 12) and women (n = 25) with MetS were instructed to follow a moderate carbohydrate-restricted diet (<30% energy) and randomly assigned to consume either three whole eggs (EGG, n = 20) or egg substitute (SUB, n = 17)/d for 12 weeks. Dietary intake, MetS parameters, and body composition were assessed at baseline and post-intervention. RESULTS Total carbohydrate (P < .001) intake decreased in all participants over time. The EGG group consumed more dietary cholesterol (P < .001) and choline (P < .001) than the SUB group. MetS was reduced in both groups, with improvements noted in dyslipidemia and decreases in waist circumference (P < .01), weight (P < .001), and percent body fat (P < .001). Reductions in plasma tumor necrosis factor-α (P < .001) and serum amyloid A (P < .05) were seen in the EGG group only. Notably, increases in dietary cholesterol were associated with reductions in plasma tumor necrosis factor-α (r = -0.340, P = .04). Plasma C-reactive protein, adiponectin, interleukin-6 interleukin-10, and cell adhesion molecules were unaffected by the intervention. CONCLUSIONS These results demonstrate that on a moderate carbohydrate background diet, accompanied by weight loss, the inclusion of whole eggs improves inflammation to a greater extent than yolk-free egg substitute in those with MetS.

A Mediterranean-style low-glycemic-load diet increases plasma carotenoids and decreases LDL oxidation in women with metabolic syndrome ☆

Thirty-five women with metabolic syndrome and high plasma low-density lipoprotein (LDL) cholesterol (≥100 mg/dl) participated in a dietary intervention consisting of a Mediterranean-style low-glycemic-load diet for 12 weeks. Participants were randomly allocated to consume diet only (n=15) or diet plus a medical food containing soy protein and plant sterols (n=20). Plasma concentrations of carotenoids, lipoprotein subfractions and oxidized LDL (OxLDL) were measured. Independent of treatment, women had a significant increase in plasma lutein (P<.0001) and β-carotene (P<.0001), while plasma lycopene was reduced (P<.05) after 12 weeks. Low-density lipoprotein cholesterol was reduced from 138±35 to 114±33 mg/dl (P<.0001). In addition, decreases were observed in the atherogenic subfractions: large very low-density lipoprotein (P<.05), small LDL (P<.00001) and medium high-density lipoprotein (P<.05). Oxidized LDL was significantly reduced by 12% in both groups (P<.01). Changes in OxLDL were inversely correlated with plasma lutein (r=-.478, P<.0001). The data indicate that women complied with the dietary regimen by increasing fruits and vegetable intake. Decreased consumption of high-glycemic foods frequently co-consumed with lycopene-rich tomato sauce such as pasta and pizza may be responsible for the lowering of this carotenoid in plasma after 12 weeks. These results also suggest that plasma lutein concentrations may protect against oxidative stress by reducing the concentrations of OxLDL.

One Egg per Day Improves Inflammation when Compared to an Oatmeal-Based Breakfast without Increasing Other Cardiometabolic Risk Factors in Diabetic Patients

There is concern that egg intake may increase blood glucose in patients with type 2 diabetes mellitus (T2DM). However, we have previously shown that eggs reduce inflammation in patients at risk for T2DM, including obese subjects and those with metabolic syndrome. Thus, we hypothesized that egg intake would not alter plasma glucose in T2DM patients when compared to oatmeal intake. Our primary endpoints for this clinical intervention were plasma glucose and the inflammatory markers tumor necrosis factor (TNF)-α and interleukin 6 (IL-6). As secondary endpoints, we evaluated additional parameters of glucose metabolism, dyslipidemias, oxidative stress and inflammation. Twenty-nine subjects, 35–65 years with glycosylated hemoglobin (HbA1c) values <9% were recruited and randomly allocated to consume isocaloric breakfasts containing either one egg/day or 40 g of oatmeal with 472 mL of lactose-free milk/day for five weeks. Following a three-week washout period, subjects were assigned to the alternate breakfast. At the end of each period, we measured all primary and secondary endpoints. Subjects completed four-day dietary recalls and one exercise questionnaire for each breakfast period. There were no significant differences in plasma glucose, our primary endpoint, plasma lipids, lipoprotein size or subfraction concentrations, insulin, HbA1c, apolipoprotein B, oxidized LDL or C-reactive protein. However, after adjusting for gender, age and body mass index, aspartate amino-transferase (AST) (p < 0.05) and tumor necrosis factor (TNF)-α (p < 0.01), one of our primary endpoints were significantly reduced during the egg period. These results suggest that compared to an oatmeal-based breakfast, eggs do not have any detrimental effects on lipoprotein or glucose metabolism in T2DM. In contrast, eggs reduce AST and TNF-α in this population characterized by chronic low-grade inflammation.

Grape Consumption Increases Anti-Inflammatory Markers and Upregulates Peripheral Nitric Oxide Synthase in the Absence of Dyslipidemias in Men with Metabolic Syndrome

We evaluated the effects of grape consumption on inflammation and oxidation in the presence or absence of dyslipidemias in metabolic syndrome (MetS). Men with MetS (n = 24), 11 with high triglycerides and low HDL and 13 with no dyslipidemia were recruited and randomly allocated to consume daily either 46 g of lyophilized grape powder (GRAPE), equivalent to 252 g fresh grapes, or placebo with an identical macronutrient composition and caloric value as GRAPE for four weeks. After a three-week washout, participants followed the alternate treatment. We measured changes between placebo and GRAPE periods in inflammatory and oxidative stress markers both in circulation and in gene expression. Changes in plasma adiponectin (p < 0.05), interleukin (IL)-10 (p < 0.005) and in mRNA expression of the inducible isoform of nitric oxide synthase (iNOS) (p < 0.25) were increased in the GRAPE compared to the placebo period only in those individuals without dyslipidemia. Additionally, plasma IL-10 was negatively correlated with NOX2 expression, a marker of oxidative stress (r = −0.55, p < 0.01), while iNOS expression was positively correlated with the expression of superoxide dismutase 2 (r = 0.642, p < 0.01), a key anti-oxidative enzyme. Grape consumption displayed anti-oxidative and increased anti-inflammatory markers in the absence of the inflammatory milieu associated with dyslipidemias.

A Larger Body Mass Index is Associated with Increased Atherogenic Dyslipidemia, Insulin Resistance, and Low-Grade Inflammation in Individuals with Metabolic Syndrome

BACKGROUND The consequences of increased body mass index (BMI) on the metabolic disorders associated with metabolic syndrome (MetS) have not been thoroughly examined. METHODS We analyzed data from 262 individuals, 97 men and 165 women (aged 18-70 years), classified with MetS to investigate whether variations in BMI could be associated with parameters of dyslipidemia, insulin resistance, or low-grade inflammation. We hypothesized that increases in BMI would positively correlate with the major dysregulations in metabolism that define MetS. For this purpose, individuals were separated into four subgroups based on their BMI: normal weight (<25 kg/m(2)), overweight (≥25 to <30 kg/m(2)), obese (≥30 to <40 kg/m(2)), and morbidly obese (≥40 kg/m(2)). RESULTS As expected, body weight and waist circumference increased significantly as BMI increased (P < 0.0001). Both systolic and diastolic blood pressure were lower in the normal BMI group compared with the other three BMI groups (P = 0.001). Markers of HDL metabolism were adversely impacted in elevated BMI groups, as both high-density lipoprotein cholesterol (HDL-C) and large HDL decreased as BMI increased (P = 0.01). BMI was negatively correlated with HDL-C (r = -0.193, P = 0.002), HDL size (r = (-)0.227, P = 0.002), and large HDL (r = -0.147, P = 0.037). In addition, plasma insulin was highest in subjects classified as morbidly obese (P < 0.0001). There was also a strong positive correlation between BMI and plasma insulin (r = 0.413, P < 0.0001), whereas adiponectin, a marker of insulin sensitivity, was negatively correlated with BMI (r = -0.288, P = 0.001). Finally, BMI was positively correlated with proinflammatory C-reactive protein (r = 0.312, P = 0.0001) and interleukin-6 (r = 0.238, P = 0.001). CONCLUSIONS The data from this study suggest that the physiological factors associated with increased BMI exacerbate the metabolic abnormalities characteristic of MetS.

Low HDL cholesterol is associated with increased atherogenic lipoproteins and insulin resistance in women classified with metabolic syndrome

Both metabolic syndrome (MetS) and elevated LDL cholesterol (LDL-C) increase the risk for cardiovascular disease (CVD). We hypothesized that low HDL cholesterol (HDL-C) would further increase CVD risk in women having both conditions. To assess this, we recruited 89 women with MetS (25-72 y) and LDL-C ≥ 2.6 mmol/L. To determine whether plasma HDL-C concentrations were associated with dietary components, circulating atherogenic particles, and other risk factors for CVD, we divided the subjects into two groups: high HDL-C (H-HDL) (≥ 1.3 mmol/L, n = 32) and low HDL-C (L-HDL) (< 1.3 mmol/L, n = 57). Plasma lipids, insulin, adiponectin, apolipoproteins, oxidized LDL, Lipoprotein(a), and lipoprotein size and subfractions were measured, and 3-d dietary records were used to assess macronutrient intake. Women with L-HDL had higher sugar intake and glycemic load (P < 0.05), higher plasma insulin (P < 0.01), lower adiponectin (P < 0.05), and higher numbers of atherogenic lipoproteins such as large VLDL (P < 0.01) and small LDL (P < 0.001) than the H-HDL group. Women with L-HDL also had larger VLDL and both smaller LDL and HDL particle diameters (P < 0.001). HDL-C was positively correlated with LDL size (r = 0.691, P < 0.0001) and HDL size (r = 0.606, P < 0.001), and inversely correlated with VLDL size (r = -0.327, P < 0.01). We concluded that L-HDL could be used as a marker for increased numbers of circulating atherogenic lipoproteins as well as increased insulin resistance in women who are already at risk for CVD.

Egg Intake during Carbohydrate Restriction Alters Peripheral Blood Mononuclear Cell Inflammation and Cholesterol Homeostasis in Metabolic Syndrome

Egg yolk contains bioactive components that improve plasma inflammatory markers and HDL profiles in metabolic syndrome (MetS) under carbohydrate restriction. We further sought to determine whether egg yolk intake affects peripheral blood mononuclear cell (PBMC) inflammation and cholesterol homeostasis in MetS, as HDL and its associated lipid transporter ATP-binding cassette transporter A1 (ABCA1) reduce the inflammatory potential of leukocytes through modulation of cellular cholesterol content and distribution. Thirty-seven men and women classified with MetS consumed a moderate carbohydrate-restricted diet (25%–30% of energy) for 12 weeks, in addition to consuming either three whole eggs per day (EGG) or the equivalent amount of yolk-free egg substitute (SUB). Interestingly, lipopolysaccharide-induced PBMC IL-1β and TNFα secretion increased from baseline to week 12 in the SUB group only, despite increases in PBMC toll-like receptor 4 (TLR4) mRNA expression in the EGG group. Compared to baseline, ABCA1 and 3-hydroxy-3-methyl-glutaryl (HMG)-CoA reductase mRNA expression increased by week 12 in the EGG group only, whereas changes in PBMC total cholesterol positively correlated with changes in lipid raft content. Together, these findings suggest that intake of whole eggs during carbohydrate restriction alters PBMC inflammation and cholesterol homeostasis in MetS.

Consuming Two Eggs per Day, as Compared to an Oatmeal Breakfast, Decreases Plasma Ghrelin while Maintaining the LDL/HDL Ratio

Eggs contain high quality protein, vitamins, minerals and antioxidants, yet regular consumption is still met with uncertainty. Therefore, the purpose of this study was to compare the effects of consuming two eggs per day or a heart-healthy oatmeal breakfast on biomarkers of cardiovascular disease (CVD) risk and satiety measures in a young, healthy population. Fifty subjects participated in a randomized crossover clinical intervention; subjects were randomly allocated to consume either two eggs or one packet of oatmeal per day for breakfast for four weeks. After a three-week washout period, participants were allocated to the alternative breakfast. Fasting blood samples were collected at the end of each intervention period to assess plasma lipids and plasma ghrelin. Subjects completed visual analog scales (VAS) concurrent to dietary records to assess satiety and hunger. Along with an increase in cholesterol intake, there were significant increases in both low-density lipoprotein (LDL) and high-density lipoprotein (HDL) cholesterol following the egg consumption period (p < 0.01). However, there was no difference in the LDL/HDL ratio, a recognized biomarker of CVD risk, nor in the plasma glucose, triglycerides or liver enzymes, between diet periods. Several self-reported satiety measures were increased following the consumption of eggs, which were associated with lower plasma ghrelin concentrations (p < 0.05). These results demonstrate that compared to an oatmeal breakfast, two eggs per day do not adversely affect the biomarkers associated with CVD risk, but increase satiety throughout the day in a young healthy population.