Abstract
Cholesterol hypothesis implied that reducing the intake of saturated fats and cholesterol while increasing that of polyunsaturated oils is effective in lowering serum cholesterol, and thereby reducing coronary heart disease (CHD). However, long-term dietary interventions based on the cholesterol hypothesis resulted in no significant decreases in serum cholesterol, but brought about significant increases in CHD and/or all-cause mortality rates. Among general populations over 40-50 years of age, the major risk factor for atherosclerosis-related diseases was not hypercholesterolemia but was high n-6/n-3 ratio of dietary and tissue lipids. Recently, social movements to exclude trans-fatty acids from our food environment have been rapidly in progress. As alternative oils, the supply of palm oil and palm kernel oil is increasing. Currently, they occupy 20% of the total plant oils supplied in Japan. However, the safety of palm oil for human nutrition has not been established as it exhibited unusual cancer-promoting activity and survival-shortening activity in rodents. Minor, unidentified components other than triacylglycerol and phytosterols in palm oil as well as in several other vegetable oils are presumed to cause such effects. Compared with these vegetable oils, animal fats are relatively safe, and their consumption is recommended within a range that does not lead to over-nutrition.
