Abstract
Atherosclerotic disease is one of the major causes of mortality in Japan. Modifiable environmental factors, diet and lifestyle, in particular, are largely responsible for the increased risk of atherosclerotic disease. However, the role of specific dietary factors had not been clearly defined until recently. Meta-analysis of prospective epidemiological studies showed that there is no conclusive evidence that dietary saturated fat is associated with an increased risk of coronary heart disease (CHD) or cardiovascular disease (CVD). This means that risks of atherosclerosis are influenced by the specific nutrients used to replace saturated fatty acids (SFAs). Studies showed that consuming polyunsaturated fatty acids (PUFAs) in place of SFAs reduces CHD events, and that replacing SFAs with carbohydrates is modestly associated with a higher risk of CHD. However, a study suggested that replacing SFAs with carbohydrates of low-glycemic index (GI) value is associated with a lower risk of CHD. In addition, not only an increase in serum LDL, but also a decrease in HDL and elevated triglycerides (TG) levels, which are often accompanied by an increase in small dense LDL, are known to accelerate the atherosclerotic process. It is important to understand the effects of SFAs and other nutrients used for replacing SFAs on lipid metabolism. Although no significant relationship has been found to date between egg consumption and CHD or CVD, reducing cholesterol absorption was shown to be effective in lowering CVD risk in clinical studies. Further studies on the appropriate amount of cholesterol intake are necessary.
