Proponents of the cholesterol theory of cardiovascular disease generally regard eggs as particularly damaging to cardiovascular health. This flawed and illogical premise is based on the fact that eggs contain high levels of cholesterol in their yolks. However, it is well evidenced that dietary cholesterol does not influence plasma cholesterol. In fact, the accumulated observational and clinical data show that dietary cholesterol, and therefore by extension egg yolks, do not contribute to the aetiology of cardiovascular disease through increases in plasma cholesterol. Further, the cause and effect of the association between cholesterol and cardiovascular disease is also misunderstood by many and often deliberately obfuscated by others. For while plasma cholesterol levels my be elevated in individuals suffering from cardiovascular disease, plasma cholesterol is provably not that cause of atherosclerosis. In fact those with very high intakes of cholesterol from eggs show no deleterious effects with regard their plasma cholesterol or symptoms of cardiovascular disease compared to those with low intakes.
For example, researchers have investigated the effects of eggs on the serum lipid levels of 25 black African egg farm workers1. The subjects had a mean cholesterol intake of 1240 mg per day, because of their high consumption of eggs. However, the fat in their diet was only 20% because they ate few sources of lipids other than eggs. A control group of matched subjects was comprised of rural black Africans who did not consume high intakes of eggs and who had cholesterol intakes of only 100 to 200 mg per day. The subjects consuming high intakes of eggs had low density lipoprotein (LDL) cholesterol concentrations that were significantly higher compared to controls. However, they also had high levels of high density lipoprotein (HDL) cholesterol. This resulted in the HDL cholesterol making up a higher percentage of total cholesterol in the egg consumers compared to the controls. However, when compared to data from Western living black Americans, total cholesterol was much lower and HDL much higher in the rural African subjects.
From this data it is tempting to speculate that consumption of eggs can influence plasma levels of cholesterol. However, caution should always be exercised because other dietary components change when cholesterol intake is modified. In particular, fibre intake has an influence on plasma cholesterol concentrations and this should always be taken into account. For example, in this study, the egg consumers ingested 10.7 grams per day of total dietary fibre, while the non-egg consumers ingested 14.0 grams per day of fibre. This therefore could explain the lower levels of total, LDL and HDL cholesterol in the non-egg consuming subjects. In addition, the egg consumers had much higher levels of sucrose (55.0 grams per day) compared to the non-egg consumers (30.4 grams per day). Considering that fructose is able to cause plasma lipid changes and that sucrose contains a moiety of fructose, it is interesting as to why the researchers overlooked this important observation. The study could just have accurately been titled ‘sucrose is associated with raised levels of plasma lipoproteins’.
RdB
