In the past few decades, eggs have been virtually synonymous with cholesterol, but we sometimes still hear claims that eggs can be part of a "healthful" diet. It is true that most of the cholesterol in our blood is synthesized from saturated fats, which come mainly from animal products, including eggs. But the cholesterol in foods does account for about 20% of our body's cholesterol, so it remains an issue.
A few studies, especially those backed by the egg industry, seem to indicate that people can increase their egg consumption yet not suffer increases in cholesterol. The reason is that once cholesterol intake exceeds 300 mg a day, further increases make little difference. An optimal diet contains minimal cholesterol, certainly less than 100 mg a day.
However, eating cholesterol-rich foods like eggs may increase the risk of heart disease independent of any cholesterol-elevating effect. The rise in chylomicrons (fat-rich particles) in the blood after a cholesterol-rich meal may directly promote atherosclerosis (hardening of the arteries).1 Further, egg consumption increases the tendency of LDL-cholesterol (the "bad" form) to become oxidized,2 and this in turn facilitates the development of atherosclerosis.
Some but not all studies have shown an increasing risk of ovarian cancer with increasing egg consumption. Whether the cholesterol content of eggs is related to this finding is not clear.
From the nutrition standpoint, eggs do not provide any nutrients that cannot otherwise be easily obtained. Their ability to act as a binder makes them useful in cooking, but satisfactory alternatives exist, including ground flaxseed in water, Ener-G(r) egg replacer, and mashed bananas or tofu.
1Zilversmit DB. Atherogenesis: a postprandial phenomenon. Circulation 1979;60:473-485.
2 Levy Y, Maor I, Presser D, Aviram M. Consumption of eggs with meals increases the susceptibility of human plasma and low-density lipoprotein to lipid peroxidation. Ann Nutr Metab 1996;40:243-251.