Ginsberg et al. 1994. A dose-response study of the effects of dietary cholesterol on fasting and postprandial lipid and lipoprotein metabolism in healthy young men. Arterioscler. Thrombosis 14:576-586
-There was no evidence that changes in dietary cholesterol intakes altered the postprandial plasma lipoprotein profile (lipoproteins thought to be involved in the development of atherosclerosis) and thus did not alter the atherogenic potential of the plasma lipoproteins. The data indicate that in the majority of healthy young men addition of two eggs per day to a low-fat diet has little effect on plasma cholesterol levels.
Schnohr et al. 1994. Egg consumption and high-density-lipoprotein cholesterol. J. Intern. Med. 235:249-251.
To determine the effects of egg consumption on plasma HDL cholesterol levels, twenty-four adults added two eggs per day to their usual diets for six weeks. Total cholesterol levels were increased by 4% while HDL cholesterol levels increased 10%. The dose adjusted response to the change in dietary cholesterol was 2.4 mg/dl per 100 mg/day. The authors concluded that "a moderate egg intake should not be rigorously restricted in healthy individuals."
McComb et al. 1994. Attenuated hypercholesterolemic response to a high-cholesterol diet in subjects heterozygous for the apolipoprotein A-IV-2 allele.N. Engl. J. Med. 331:706-710.
Genetic factors contribute to the variability of the plasma lipid responses to dietary cholesterol and in this study it was shown that subjects with the apolipoprotein A-IV-2 allele have an attenuated response to a dietary cholesterol challenge. Subjects were fed a low-cholesterol diet and one with 1100 mg/day added cholesterol. The change in plasma cholesterol in subjects without the apo A-IV-2 allele (n=12) was 22 mg/dl (dose adjusted: 2.3 mg/dl per 100 mg/day) while for those with the apo A-IV-2 allele (n=11) the change was 6 mg/dl (dose adjusted: 0.7 mg/dl per 100 mg/day). It is estimated that one in every seven individuals in the United States has the apo A-IV-2 allele and, based on the data from this study, has a genetic resistance to the plasma cholesterol raising effects of very high intakes of dietary cholesterol. These findings are a breakthrough in beginning to understand the role of genetic factors in the variability of plasma lipid responses to dietary cholesterol.
Lichtenstein et al. 1994. Hypercholesterolemic effect of dietary cholesterol in diets enriched in polyunsaturated and saturated fat. Dietary cholesterol, fat saturation, and plasma lipids. Arterioscler. Thromb. 14:168-175.
-Studies in fourteen men (n=8) and women (n=6) fed either corn oil (polyunsaturated fat) or beef tallow (saturated fat) with or without addition of 197-226 mg cholesterol per 1000 kcal, documented little effect of dietary fat saturation on the plasma cholesterol response to dietary cholesterol. In the corn oil fed group the addition of cholesterol increased plasma cholesterol 11 mg/dl (dose adjusted: 3.9 mg/dl per 100 mg/day) and in the beef tallow group the increase was the same, 11 mg/dl (dose adjusted: 3.8 mg/dl per 100 mg/day). The findings are consistent with other studies which indicate that with a 30% fat diet, the plasma cholesterol response to dietary cholesterol is independent of the fatty acid composition of the diet. The study also provides evidence which suggests that resistance to the effects of dietary cholesterol occurs in older men and women and is not limited to only young, healthy volunteers.
Tell your parents that middle aged patients have been found to be more sensitive to increases in dietary cholesterol as opposed to younger patients(*). That means while the eggs are just fine for you, they may or may not be for your dad...who I am sure is having regular blood work done in order to know his own cholesterol data.
*-Knopp et al. 1996. A double-blind, randomized trial of the effects of two eggs per day in moderately hypercholesterolemic and combined hyperlipidemic subjects consuming the NCEP Step I diet. (Reported in abstract at the November 1995 American Heart Association meeting in Anaheim, CA)