Human plasma lipid and immunologic responses to eggs and ascorbic acid

Abstract

The possibility that dietary eggs and ascorbic acid have a positive and synergistic influence on human high density lipoprotein (HDL) cholesterol was investigated. The influences of these diet variables on other plasma lipids and on some immune functions were also evaluated. Twenty men, ages 36 to 60 years, followed each of four, 12-week modifications of their daily habitual diet: no visible eggs or supplemental ascorbic acid (Basal); 3 eggs (EG); 1.5 g ascorbic acid (AA); and both 3 eggs and 1.5 g ascorbic acid (EGAA). Although average HDL cholesterol concentrations were unchanged by these diet modifications, HDL cholesterol was positively correlated with plasma levels of ascorbic acid. Total cholesterol was the only plasma lipid that was affected significantly by any of the treatments, and the difference was only between diets EG and AA (mean±SEM); 209±9 mg/dl and 194±6 mg/dl, respectively. These diet variables had no significant effect on plasma concentrations of immunoglobulins IgG, IgA, IgM, IgD, or complement C3 nor on mitogen-induced lymphoproliferation. However, the latter measure of immune response, mitogen-induced lymphoproliferation, tended to increase during the AA diet period. Although these data do not support an eggs-ascorbic acid synergism, ascorbic acid appears to play a role, as yet undefined, in cholesterol metabolism.