RELATIONSHIP BETWEEN POSTPRANDIAL LIPEMIA AND LDL PARTICLE SIZE DURING A KETOGENIC DIET IN MEN

Abstract

Individuals exhibiting a predominance of small dense LDL-cholesterol (LDL) particles have been termed “pattern B”, which is associated with a greater than three-fold risk of coronary heart disease in men. This atherogenic phenotype may be partially driven by a delayed clearance of triacylglycerols (TAG) after a fat-rich meal (i.e., abnormal postprandial lipemia). Thus, a reduction in postprandial lipemia should result in a shift to a larger LDL particle profile. PURPOSE This study determined factors related to changes in peak LDL diameter resulting from a ketogenic diet, which was previously shown by our laboratory to result in decreased postprandial lipemia. METHODS Twenty-five healthy men consumed a ketogenic diet for six weeks. Fasting blood draws and an oral fat tolerance test were performed before and after the diet. Relationships between the change in peak LDL diameter and changes in blood lipids, insulin, and percent body fat were assessed. RESULTS The ketogenic diet resulted in significant (P < 0.05) changes in fasting serum TAG (−39%), postprandial lipemia (−33%), insulin (−40%), percent body fat (−11%), and peak LDL diameter (+1.8%). There were no significant changes in total cholesterol, LDL or HDL. There was a significant relationship between peak LDL particle diameter and fasting TAG (r = 0.41) at the start of the study. The only variable significantly related to the change in peak LDL diameter was the change in fasting TAG (r = 0.41) and the change in postprandial lipemia (r = 0.50). Thus, approximately 25% of the variance in peak LDL diameter responses to a ketogenic diet was accounted for by changes in postprandial lipemia. CONCLUSION These data indicate that a ketogenic diet has favorable effects on postprandial lipemia and peak LDL size in men and provides support for the notion that an impaired ability to clear circulating TAG after a meal contributes to a small atherogenic LDL profile. Sponsored by a grant from the Atkins Foundation, New York, NY