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J Am Coll Nutr. 2010 Dec;29(6):595-603.

Effects of diets high in walnuts and flax oil on hemodynamic responses to stress and vascular endothelial function.

Author information

  • 1Department of Biobehavioral Health, The Pennsylvania State University, University Park, Pennsylvania 16802, USA. sgw2@psu.edu

Abstract

BACKGROUND:

Polyunsaturated fatty acids (PUFA) have beneficial effects on cardiovascular risk, although the mechanisms are incompletely understood. In a previous article, we showed significant reductions in low-density lipoprotein cholesterol and several markers of inflammation with increasing intake of alpha-linolenic acid (ALA) from walnuts and flax.

OBJECTIVE:

To examine effects of ALA on cardiovascular responses to acute stress, flow-mediated dilation (FMD) of the brachial artery, and blood concentrations of endothelin-1 and arginine-vasopressin (AVP).

DESIGN:

Using a randomized, crossover study design, cardiovascular responses to acute stress were assessed in 20 hypercholesterolemic subjects, a subset of whom also underwent FMD testing (n  =  12). Participants were fed an average American diet (AAD) and 2 experimental diets that varied in the amount of ALA and linoleic acid (LA) that they contained. The AAD provided 8.7% energy from PUFA (7.7% LA, 0.8% ALA). On the LA diet, saturated fat was reduced, and PUFA from walnuts and walnut oil provided 16.4% of energy (12.6% LA, 3.6% ALA). On the ALA diet, walnuts, walnut oil, and flax oil provided 17% energy from PUFA (10.5% LA, 6.5% ALA).

RESULTS:

The ALA and LA diets significantly reduced diastolic blood pressure (-2 to -3 mm Hg) and total peripheral resistance (-4%), and this effect was evident at rest and during stress (main effect of diet, p < 0.02). FMD increased (+34%) on the diet containing additional ALA. AVP also increased by 20%, and endothelin-1 was unchanged.

CONCLUSIONS:

These results suggest novel mechanisms for the cardioprotective effects of walnuts and flax, and further work is needed to identify the bioactives responsible for these effects.

PMID:
21677123
[PubMed - indexed for MEDLINE]
PMCID:
PMC3862179
Free PMC Article

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