There are a number of known risk factors associated with developing cardiovascular disease. These include a number of changes in blood lipids including increases in plasma LDL cholesterol, increases in triglycerides, decreases in HDL cholesterol, as well as the phenotypic expression of the pattern B subfraction of small dense LDL cholesterol. A number of dietary factors are know to modify blood lipids including fish oil, fibre, phytonutrients such as sterols and garlic. High concentrations of dietary cholesterol are recognised by mainstream medical authorities as being linked to detrimental changes in blood lipid levels, however the role for dietary cholesterol in the development of cardiovascular disease is controversial. While in certain individuals with a particular genetic make up, cholesterol intakes may have an influence on blood lipid levels, amongst the majority of healthy individuals this appears not to be the case.
For example, research1 has investigated the effects of dietary cholesterol from whole eggs on the changes to blood lipids in Mexican children aged between 8 and 12. The children (25 boys and 29 girls) were assigned to receive either 2 whole eggs per day which equated to around 518 mg of cholesterol extra in their diet, or a similar amount of egg whites which contained no cholesterol. After 30 days of treatment the children followed a normal diet for 2 weeks before being assigned to the opposite group. Subjects that had increases in total blood cholesterol of ≥0.06 mmol/L (hyperesponders) after whole egg treatment showed elevations in both LDL cholesterol and HDL cholesterol but no change in the LDL to HDL ratio. Those subjects who had a total blood cholesterol rise of ≤0.05 mmol/L (hyporesponders) also had no changes to their LDL:HDL ratio.
These results support a growing body of research that questions that dietary cholesterol is responsible for deleterious changes in blood lipids. Even in those subjects who had the largest increase in total cholesterol blood levels (≥0.06 mmol/L) in response to the whole egg treatment, the ratio of LDL:HDL remained constant suggesting that cardiovascular disease risk had not changed. Interestingly, in all subjects the whole egg consumption caused increases in LDL diameter and a decrease in the small LDL subfractions that are known risk factors for cardiovascular disease. In the study 15% of the subjects were identified as having the high risk LDL phenotype B, but on consumption of eggs changed to the low risk pattern A phenotype. These results taken together suggest that cholesterol from eggs in not detrimental to blood lipids, but may actually be beneficial in certain individuals.
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