Topical Area: Energy and Macronutrient Metabolism
Objectives : It has been demonstrated that some individuals (approximately 1/3 of the population) can be classified as hyper-responders to dietary cholesterol. The objective of this study was to evaluate whether the response to dietary cholesterol (provided by eggs) would affect lipoprotein metabolism and the bioavailability of lutein, zeaxanthin and choline, nutritional components present in eggs
We recruited 36 healthy subjects who underwent a two-week washout period in which they consumed zero eggs. Participants were then fed 3 eggs (540 additional mg of dietary cholesterol) for 4 weeks. Plasma lipids were measured by use of an automated chemical clinical analyzer; the number of large and small LDL and HDL particles were measured by Nuclear Magnetic Resonance. Plasma lutein and zeaxanthin were determined by use of HPLC and plasma choline by use of LSM spectroscopy. We classified the normal response to dietary cholesterol as 2.2 mg/dL for each additional 100 mg of dietary cholesterol. Therefore, those individuals who had > 12 mg/dL increase in plasma cholesterol after the intervention (n = 12) were considered hyper-responders while the other 24 subjects who presented changes in plasma cholesterol ranging from -16 to 9 mg/dL were considered hypo-responders.
Results : Compared to zero eggs, hyper-responders had significant increases in plasma total, LDL and HDL cholesterol (p< 0.001) with no changes in the LDL/HDL ratio. They also had higher concentrations of large LDL (p < 0.01) with no changes in small LDL. In contrast no changes in plasma total LDL or HDL cholesterol or large LDL were observed in hypo-responders after the consumption of 3 eggs/day. Interestingly, both hypo and hyper-responders had significant increases in large HDL particles (12%), plasma lutein (17%), zeaxanthin (30%) and choline (12%) (p< 0.001) compared to zero egg intake.
Conclusions : These results suggest that egg intake increases the bioavailability of carotenoids and choline present in eggs independently of plasma cholesterol response to dietary cholesterol. Further, the observed increases in large HDL in all individuals could be associated with HDL being a major transporter of lutein and zeaxanthin in plasma
Funding Sources : The Esperance Family and the Egg Nutrition Center