[Diet and hypertriglyceridemia: influence of dietary modifications on plasma lipids, lipoproteins and apoproteins in patients with primary hypertriglyceridemia].

BACKGROUND: To investigate the influence of dietary changes on plasma lipoproteins and apoproteins in 10 patients with hypertriglyceridemia (plasma triglycerides greater than 1000 mg/dl). METHODS: A sequential study with three periods was designed: 1) Inclusion with uncontrolled free diet; 2) Two weeks of a diet with about 1000 calories/day, controlled with a daily survey; and 3) One week of "free" diet of about 2000 calories. At the end of the three periods the following were measured in each patient: weight, glycemia, plasma IRI and C-peptide, plasma, triglycerides, cholesterol, chylomicron, VLDL, LDL and HDL cholesterol. At the end of the second and third periods the caloric and immediate principles intake were individually considered. RESULTS: A reduction in plasma cholesterol and triglycerides was observed in all cases after the caloric reduction, and also a disappearance of chylomicrons. The reduction of triglycerides took place in all lipoproteins. By contrast, after the low-calorie diet only the VLDL-cholesterol was reduced, while LDL- and HDL-cholesterol increased. The apo C-III/apo C-II ratio was significantly reduced after the low-calorie diet. The plasma glycemia, IRI and C-peptide were negatively correlated with LDL-cholesterol and with the apo C-III/apo C-II ratio. The best model to explain the oscillations of plasma triglycerides depending on the diet was that including the three ingested immediate principles together with the total diet calories. CONCLUSIONS: During the caloric restriction there would be an increased catabolism of VLDL to LDL. This reduction would be mediated by C-III and C-II apoproteins, probably through the oscillations of plasma IRI.