Arterial compliance in obese subjects is improved with dietary plant n-3 fatty acid from flaxseed oil despite increased LDL oxidizability.
Arterial compliance in obese subjects is improved with dietary plant n-3 fatty acid from flaxseed oil despite increased LDL oxidizability.
Year: 1997
Authors: P J Nestel, S Pomeroy, T Sasahara, T Yamashita, Y L Liang, A M Dart, G L Jennings, et al.
Publication Name: Arterioscler. Thromb. Vasc. Biol.
Publication Details: Volume 17; Page 6.
Abstract:
Arterial function can be measured in vivo by assessing the compliance or distensibility of the large arterial system, and the reactivity of the microcirculation within the forearm and coronaries. Arterial compliance or elasticity declines with aging, hypertension, hypercholesterolemia, and diabetes. Alternatively, it can be improved with fish oil feeding. Arterial compliance reflects the relationship between pressure and volume in the proximal arterial system and in the thoracic aorta. Stiffness of these arteries increases with structural changes due to atherosclerosis and aging. The objective of the present study was to examine the effects of a high ALA flaxseed oil diet on systemic arterial compliance. Fifteen obese subjects were fed four diets consecutively, each for a four week period. The diets consisted of a high SFA (51%)/high fat (36% – SHF); a high flaxseed oil (20 g of ALA)/low fat (26% – ALF); a high oleic (58%)/low fat (26% – OLF) and SHF. The flaxseed oil and oleic acid oil were fed as margarines. Systemic arterial compliance was calculated from aortic flow velocity and aortic foot driving pressure. Systemic arterial compliance during the first and last SHF periods was 0.42 +/- 0.12 and 0.56 +/- 0.21 milliliters per millimeter of mercury. It rose significantly to 0.78 +/- 0.28 with the flaxseed oil diet. Systemic arterial compliance during the OLF diet was 0.62 +/- 0.19 lower than with the flaxseed oil diet. Mean arterial pressure and glucose tolerance was similar during the ALF, OLF and the second SHF periods. TC did not change following any of the diets. HDL-C decreased and LDL oxidizability increased with the ALF diet. EPA levels in LDL and plasma lipids significantly increased following the flaxseed oil diet. The marked rise in arterial compliance with the flaxseed oil diet reflected rapid functional improvement in systemic arterial compliance despite a rise in LDL oxidizability. The authors speculated that flaxseed oil may act by reducing smooth muscle tonicity, increasing endothelial mediated dilation and arterial relaxation, and/or diminishing eicosanoid mediated vasoconstriction. The apparent paradox of increased in vitro LDL oxidizability in light of the protective effects of ALA in vivo requires further experimentation. In addition, whether the beneficial effects of flaxseed oil are due to ALA itself or to its conversion to EPA remains to be elucidated. However, the authors concluded that ALA in flaxseed oil confers a novel approach to improving arterial function.
