Effect of desirable fasting triglycerides on the postprandial response to dietary fat

Background: The National Cholesterol Education Program (NCEP) recently revised the "desirable" fasting triglyceride (TG) to < 150 mg/dL, and levels exceeding 200 mg/dL are defined as "high." Methods: To evaluate the postprandial response to dietary fat, 50 studies were conducted in nonobese, normocholesterolemic subjects. Following an overnight fast, subjects consumed an oral fat load (70 g/m²), and postprandial triglyceride (ppTG) measurements were assessed at 2, 4, 6, and 8 hours. Subjects were divided by fasting TG cutpoints of 100 and 150 mg/dL. Results: The prevalence of ppTG samples exceeding 200 mg/dL was significantly lower with fasting TG < 100 mg/dL (n = 116) compared with TG 100 to 150 mg/dL (n= 56) (8% versus 25%; p=.004, chi-square analysis). In addition, fasting TG < 100 mg/dL (n = 29) was associated with a reduced mean 4-hour peak ppTG level compared with fasting TG > 100 mg/dL (n = 21) (125 mg/dL versus 249.8 mg/dL; p < .0001). Multiple linear regression analysis identified fasting TG as the most important determinant of the postprandial response after adjustment for other covariates (p = .0005). Conclusions: Because ppTG-rich lipoproteins contribute to coronary heart disease risk, fasting TG < 100 mg/dL may be a more desirable cutpoint than fasting TG < 150 mg/dL in coronary heart disease risk factor assessment.