The atheroprotective potential of n-3
alpha-linolenic acid (ALA) has not yet been fully determined, even in murine models of
atherosclerosis. We tested whether ALA-derived, n-3 long chain
polyunsaturated fatty acids (LCPUFA) could offer atheroprotection in a dose-dependent manner.
Apolipoprotein B (
ApoB)100/100LDLr-/- mice were fed with diets containing two levels of ALA from
flaxseed oil for 16 weeks.
Fish oil- and cis-monounsaturated-fat-enriched diets were used as positive and negative controls, respectively. The mice fed cis-monounsaturated fat and ALA-enriched diets exhibited equivalent plasma total
cholesterol (TPC) and
LDL-cholesterol (
LDL-c) levels; only mice fed the
fish-oil diet had lower TPC and
LDL-c concentrations. Plasma
LDL-CE
fatty acid composition analysis showed that ALA-enriched diets lowered the percentage of atherogenic
cholesteryl oleate compared with cis-monounsaturated-fat diet (44% versus 55.6%) but not as efficiently as the
fish-oil diet (32.4%). Although both ALA and
fish-oil diets equally enriched hepatic
phospholipids with
eicosapentaenoic acid (EPA) and ALA-enriched diets lowered hepatic
cholesteryl ester (CE) levels compared with cis-monounsaturated-fat diet, only
fish oil strongly protected from
atherosclerosis. These outcomes indicate that dietary n-3 LCPUFA from
fish oil and n-3 LCPUFA (mostly EPA) synthesized endogenously from ALA were not equally atheroprotective in these mice.