Title

Potential of eggs in enhancing the cardioprotective effects of carbohydrate restricted diets (CRD) in weight loss interventions

Date of Completion

January 2007

Keywords

Health Sciences, Nutrition

Degree

Ph.D.

Abstract

The main objective of this study was to evaluate the contribution of dietary cholesterol from eggs in the context of a carbohydrate restricted diet (CAD) on lipoprotein metabolism and circulating carotenoids. This was a randomized single blinded study conducted in 28 overweight/obese male subjects (BMI: 25-37 kg/m2), 40-70 y. Subjects were counseled to consume 10-15% energy from carbohydrate (CHO) and were allocated either to the EGG group [intake of 3 eggs (640 mg/d additional dietary cholesterol)] or the SUB group [equivalent amount of egg substitute (0 additional mg dietary cholesterol/d) for 12 wk. ^ During the intervention a decrease in energy intake and energy from CHO (P < 0.05) was observed for all subjects when compared to habitual intake. In addition, reductions in body weight (P < 0.001), waist circumference (P < 0.0001) and plasma triglycerides (TG) (P < 0.001) were observed in all subjects after 12 wk. Total and LDL cholesterol as well as the LDL-C/HDL-C ratio did not change during the intervention. In contrast, the EGG group had a significant increase in HDL cholesterol (HDL-C) (P < 0.001) while there were no changes in HDL-C for the SUB group. Decreases in large and medium very low density lipoprotein subclasses (P < 0.001) and apolipoprotein (apo) B (P < 0.01) were observed for both groups. In agreement with the reduction in plasma TG, a 133% increase in apo C-II and a 65% decrease in apo C-III were observed. Subjects from the EGG group had a higher concentration of large HDL and large LDL subclasses compared to the SUB group (P < 0.01). ^ Intake of carotenoids including lutein, zeaxanthin, criptoxanthine, β-carotene and α-carotene were similar between the EGG and SUB groups at baseline, 6 and 12 wk. However, only the EGG group presented an increase in plasma lutein (P < 0.0001) and zeaxanthin (P < 0.025) after 12 wk. ^ From these studies, we conclude that intake of 3 eggs per day enhances the beneficial effects of CRD in lipoprotein metabolism and carotenoid absorption as demonstrated by the higher concentrations of HDL–C, the increased formation of large HDL and LDL subclasses and the higher concentrations of circulating lutein and zeaxanthine in the EGG group. ^