beta-Very low density lipoproteins (beta-VLDLs) are atherogenic,
cholesterol-rich
chylomicron and VLDL remnants that accumulate in the plasma of type III dysbetalipoproteinemic subjects. To evaluate the effect of
fish oil supplementation on plasma
beta-VLDL concentrations, we compared the
lipid and
lipoprotein responses in nine type III and nine type IV hyperlipidemic subjects. Each individual received 6 g/day
omega-3 fatty acids for 12 weeks. Before treatment, the mean total
cholesterol, total
triglyceride, VLDL triglyceride,
low density lipoprotein (
LDL) cholesterol, and
high density lipoprotein (
HDL) cholesterol levels were not different between groups. Conversely,
VLDL cholesterol,
intermediate density lipoprotein (
IDL) cholesterol, and IDL
triglycerides were higher in type III than in type IV subjects.
Fish oil supplementation was associated with significantly lower levels of
cholesterol (-50%),
triglycerides (-50%), and
apolipoprotein B (-50%) in the d less than 1.006 g/ml ultracentrifugation plasma fraction in both groups, compatible with a reduction in VLDL in type III and type IV subjects, and in
beta-VLDL in type III subjects. This finding was confirmed by analysis of the plasma
zonal ultracentrifugation profile and the
agarose gel electrophoretic pattern of
lipoproteins, which showed a reduction in but not a disappearance of remnant particles, suggesting that not all
beta-VLDL had been cleared
after treatment. The levels of
IDL cholesterol and IDL
triglycerides (1.006 less than d less than 1.019 g/ml) were not affected in either group. Initially low
LDL cholesterol (1.019 less than d less than 1.063 g/ml) and
HDL cholesterol levels rose significantly in both groups. In type III hyperlipidemics, all
LDL cholesterol values remained below 120 mg/dl, whereas they were higher than 150 mg/dl
after treatment in two individuals with type IV
hyperlipidemia.(ABSTRACT TRUNCATED AT 250 WORDS)