A successful dietary treatment fails to normalize plasma triglyceride postprandial response in type IV patients

The role of plasma triglycerides as a risk factor for cardiovascular disease is still under scrutiny. While recent studies have shown that postprandial triglyceridemia is an independent risk factor, normalization of fasting plasma triglycerides through modification of nutritional habits remains the primary approach in the treatment of hypertriglyceridemia. To address the issue of whether a satisfactory dietary regimen results in the control of postprandial lipemia, 53 type IV hypertriglyceridemic patients underwent an hypolipidemic diet for 3 months. All patients had a reduction of fasting lipid parameters (average TG: from 516±208 to 229±99 mg/dl; total cholesterol (Chol): from 261±42 to 213±40 mg/dl and HDL Chol: from 33±9 to 38±8 mg/dl). Taking plasma TG≤200 mg/dl as the target for dietary intervention 26 patients were classified as ‘responders’ while the remaining 27 were ‘non responders’. Even if fasting total TG, total Chol, HDL and LDL Chol were normal, both responders and non responders (P<0.0001) showed an exaggerated postprandial response to an oral fat load as compared to controls (20 normolipidemic subjects). Also when 10 responders and 10 controls, all male, were matched for plasma TG (129±43 versus 121±41 mg/dl) and other lipid parameters, a statistically significant difference between the two groups was observed at the time of each of the postprandial tests (P<0.0001) and for the area under the curve. The fact that the post prandial response is poorly modified by a dietary regimen, that effectively reduces plasma fasting TG, suggests that commonly used dietary regimens fail to restore a normal postprandial metabolism. Whether the cardiovascular risk for these patients is reduced after diet remains, therefore, to be addressed.