Eggs have a high concentrations of cholesterol. The high cholesterol content of eggs has lead many to question the health effects of eggs. However this questioning stems from the erroneous belief that eggs can negatively affect blood lipid levels. That eggs do not affect cholesterol levels of healthy subjects has been fairly well evidenced in the literature using clinical trials. Further it is known that eggs consumption is not able to alter the cholesterol levels of those with type 2 diabetes. For example, in one study1, researchers compared the lipid effects of consuming more than 2 eggs per day (6 days per week) over a 3 month period, with consumption of less than 2 eggs per day (6 days per week) over the same time period. These subjects were enrolled following a period of weight loss. During this time there was no difference in the lipid profiles of the two groups, suggesting the eggs were not able to alter plasma lipoprotein levels. However, those subject eating more eggs reported greater levels of satiety.
While some epidemiological studies have shown associations between egg consumption and changes in blood lipids, these studies do not measure cause and effects and no cause and effect can be inferred from the data. It is well known that egg consumption is associated with other nutritional habits, and some of these habits have been shown to affect plasma lipid levels. It is therefore not possible to say that the eggs have caused the increase in plasma cholesterol levels reported in observational studies. The fact that clinical trials show no effect for eggs on plasma cholesterol levels, supports the view that eggs are not the variable causing increases in plasma cholesterol in observational studies. While eggs are not able to alter plasma lipoprotein levels, they are able to influence health in other ways. Eggs are a very good source of a number of nutrients, including essential fats, protein and vitamins. The recommendation to avoid eggs is therefore not justified, in fact eggs consumption should be encouraged.
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