X-Message-Number: 24627
Date: Sun, 12 Sep 2004 11:19:28 -0700 (PDT)
From: Doug Skrecky <>
Subject: CVD prevention: Walnuts beat olive oil

Circulation. 2004 Apr 6;109(13):1609-14. Epub 2004 Mar 22
A walnut diet improves endothelial function in hypercholesterolemic
subjects: a randomized crossover trial.
 BACKGROUND: Epidemiological studies suggest that nut intake decreases
coronary artery disease (CAD) risk. Nuts have a cholesterol-lowering
effect that partly explains this benefit. Endothelial dysfunction is
associated with CAD and its risk factors and is reversed by antioxidants
and marine n-3 fatty acids. Walnuts are a rich source of both antioxidants
and alpha-linolenic acid, a plant n-3 fatty acid. METHODS AND RESULTS: To
test the hypothesis that walnut intake will reverse endothelial
dysfunction, we randomized in a crossover design 21 hypercholesterolemic
men and women to a cholesterol-lowering Mediterranean diet and a diet of
similar energy and fat content in which walnuts replaced approximately
32% of the energy from monounsaturated fat. Participants followed each
diet for 4 weeks. After each intervention, we obtained fasting blood and
performed ultrasound measurements of brachial artery vasomotor function.
Eighteen subjects completing the protocol had suitable ultrasound
studies. Compared with the Mediterranean diet, the walnut diet improved
endothelium-dependent vasodilation and reduced levels of vascular cell
adhesion molecule-1 (P<0.05 for both). Endothelium-independent
vasodilation and levels of intercellular adhesion molecule-1, C-reactive
protein, homocysteine, and oxidation biomarkers were similar after each
diet. The walnut diet significantly reduced total cholesterol
(-4.4+/-7.4%) and LDL cholesterol (-6.4+/-10.0%) (P<0.05 for both).
Cholesterol reductions correlated with increases of both dietary
alpha-linolenic acid and LDL gamma-tocopherol content, and changes of
endothelium-dependent vasodilation correlated with those of
cholesterol-to-HDL ratios (P<0.05 for all). CONCLUSIONS: Substituting
walnuts for monounsaturated fat in a Mediterranean diet improves
endothelium-dependent vasodilation in hypercholesterolemic subjects. This
finding might explain the cardioprotective effect of nut intake beyond
cholesterol lowering.

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