Salutory cardiovascular effects of walnuts

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Of interest to those not entirely avoiding ALA--

PMID: 15037535 [PubMed - indexed for MEDLINE]

Lipid Clinic at the Endocrinology and Nutrition Service, Institut

d'Investigacions Biomediques August Pi i Sunyer, Hospital Clinic,

Barcelona, Spain. eros@...

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.

Publication Types:

Clinical Trial

Randomized Controlled Trial

PMID: 15037535 [PubMed - indexed for MEDLINE]