The Effects of Dietary Flaxseed on Atherosclerotic Plaque Regression

Key Findings:

Unlike drug therapy, n-3 PUFAs have fewer and milder side effects and are generally considered safe. Milled flaxseed has been shown to be cardioprotective and anti-atherogenic in animal models as well as in clinical settings.  In rabbits fed flaxseed, a clear dissociation of circulating cholesterol levels from atherosclerotic plaque formation was found.  Flaxseed supplementation significantly accelerated the regression of atherosclerotic plaques. The high levels of n-3 fatty acids detected within the aorta may account for the observed increases in plaque regression. Further research is recommended to definitively identify the mechanism(s) by which dietary flaxseed increases plaque regression.

ABSTRACT:

Dietary flaxseed can retard the progression of atherosclerotic plaques. However, it remains unclear whether these antiatherogenic effects extend to plaque regression.  In the present study, the therapeutic potential of dietary flaxseed on atherosclerotic plaque regression and vascular contractile function was evaluated using a novel rabbit model. Rabbits were randomly assigned to receive either a regular diet for 12 wk (group I) or a 1% cholesterol-supplemented diet for 4 wk followed by a regular diet for 8 wk (group II). The remaining experimental animals were treated as in group II but were fed for an additional 14 wk with either a regular diet (group III) or a 10% flaxseed-supplemented diet (group IV). Animals in group II showed clear evidence of plaque growth stabilization. Their vessels also exhibited significantly lower norepinephrine- induced contraction and an impaired relaxation response to acetylcholine compared with animals in group I. Dietary flaxseed supplementation resulted in a significant ca. 40% reduction in plaque formation (P = 0.033). Animals in both groups II and III displayed improved contraction and endothelium-dependent vessel relaxation. Dietary flaxseed is a valuable strategy to accelerate the regression of atherosclerotic plaques; however, flaxseed intervention did not demonstrate a clear beneficial effect on the vessel contractile response and endothelium-dependent vasorelaxation. (Authors abstract)