Eggs Improve Plasma Biomarkers in Patients with Metabolic Syndrome Following a Plant-Based Diet—A Randomized Crossover Study

Abstract

Plant-based (PB) diets are considered a healthy dietary pattern; however, eggs are not always included in this dietary regime. We hypothesized that the addition of two eggs per day would increase HDL cholesterol as well as plasma lutein, zeaxanthin and choline in individuals with metabolic syndrome (MetS). In this randomized controlled crossover intervention, we recruited 30 participants (49.3 ± 8 y) with MetS who followed a PB diet for 13 weeks. A registered dietitian advised all subjects on food selection and followed them through the intervention to ensure compliance. Participants underwent a 2-week washout with no eggs or spinach (a source of dietary lutein and zeaxanthin) and were randomly allocated to consume spinach (70 g) with either two eggs (EGG) or the equivalent amount of egg substitute (SUB) for breakfast for 4 weeks. After a 3-week washout, they were allocated the alternate breakfast. A total of 24 participants (13 women/11 men) finished the intervention. Plasma lipids, glucose, insulin, anthropometrics, plasma lutein, zeaxanthin, choline and trimethylamine oxide (TMAO) were assessed at baseline and the end of each intervention. When we compared individuals consuming the EGG versus the SUB breakfast, we observed a lower body weight (p < 0.02) and a higher HDL cholesterol (p < 0.025) after the EGG diet. There were no differences in plasma LDL cholesterol, triglycerides, glucose, insulin, or blood pressure. The number of large HDL particles measured by NMR was higher after EGG (p < 0.01) as compared to SUB. Plasma choline was higher in both treatments (p < 0.01) compared to baseline (8.3 ± 2.1 μmol/L). However, plasma choline values were higher in EGG (10.54 ± 2.8 μmol/L) compared to SUB (9.47 ± 2.7 μmol/L) p < 0.025. Both breakfasts increased plasma lutein compared to baseline (p < 0.01), while plasma zeaxanthin was only increased in the egg intervention (p < 0.01). These results indicate that consuming a plant-based diet in combination with whole eggs increases plasma HDL cholesterol, choline and zeaxanthin, important biomarkers in subjects with MetS.

The Effects of Eggs in a Plant-Based Diet on Oxidative Stress and Inflammation in Metabolic Syndrome

“…This randomized, controlled, cross-over designed dietary intervention was previously reported [16]. After screening to meet the criteria for MetS, participants were asked to follow a PBD (lactovegetarian) throughout the 13-week intervention.…”

“…In addition, after a 2-week washout (without eggs and spinach), participants were randomly allocated to consume either two whole eggs per day (EGG) or the equivalent amount (1/2 c) of egg substitute with spinach (70 g) as an omelet for breakfast every day for 4 weeks. The egg substitute was egg whites from the Egg Beaters brand with zero cholesterol as described previously [16]. Following a 3-week washout, participants were assigned to the opposite treatment.…”

“…A registered dietitian advised the participants and ensured compliance with the diet. The intervention scheme was reported earlier [16]. Thirty participants (49.3 ± 8 y) classified with MetS according to National Cholesterol Education Program-Adult Treatment Panel III (NCEP-ATP III) guidelines [17] enrolled in the 13-week diet intervention.…”

“…CRP and liver enzymes alanine transaminase (ALT) and aspartate transaminase (AST) were measured using an automated clinical chemistry analyzer (Cobas C 111, Roche Diagnostics, Indianapolis, IN, USA) as previously described [16,18].…”

“…We have previously demonstrated the complementary effect of two whole eggs for 4 weeks to this protective diet, which reduced BMI and weight with corresponding increases in plasma HDL cholesterol (HDL-C), large HDL particles, and plasma choline, lutein, and zeaxanthin [16]. We reported the improvements in the dietary concentration of these nutrients and HDL-C after whole egg intake compared to egg substitutes in adults with MetS.…”