Issue 202 Item 13 Walnuts Improve Endothelial Function

Substituting walnuts for monounsaturated fatty acids (MUFA) in the Mediterranean diet improves endothelial function.
“This is the first time a whole food, not its isolated components, has shown this beneficial effect on vascular health,” lead author Emilio Ros, MD, from the Hospital Clinic of Barcelona, Spain, says in a news release. “Walnuts differ from all other nuts because of their high content of alpha-linolenic acid (ALA), a plant-based omega-3 fatty acid, which may provide additional anti-atherogenic properties.”

Other beneficial components in walnuts include L-arginine, folic acid, fiber, gamma-tocopherol, and other antioxidants, which also appear to help prevent atherosclerosis.

In this crossover-design trial, 21 men and women, aged 25 to 75 years with high cholesterol, received a cholesterol-lowering Mediterranean diet for four weeks, followed or preceded by a four-week diet of similar energy and fat content in which walnuts replaced roughly 32% of the energy from monounsaturated fat. Based on each subject’s total caloric intake, the daily intake of walnuts was approximately 1.4 to 2.3 ounces (40-65 g or 8-13 walnuts).

After each diet, subjects had fasting blood and ultrasound measurements of brachial artery vasomotor function. Eighteen subjects completed the study and had suitable ulrasound studies.

“Compared with the Mediterranean diet, the walnut diet increased endothelium-dependent vasodilation (EDV) by 64% and reduced levels of vascular cell adhesion molecule-1 by 20%,” Dr. Ros says. “In addition, as in previous studies, the walnut diet decreased total cholesterol and low-density lipoprotein (LDL) cholesterol [P < .05 for all comparisons]." Changes in EDV were inversely correlated with changes in cholesterol to high-density lipoprotein (HDL) ratios, suggesting that the benefit of the walnut diet was in part mediated by changes in the lipid profile. However, the authors suggest that other factors including ALA could be equally important. Study limitations include the use of outpatient intervention diets, and evaluation of only postprandial and not of fasting measurements of endothelial function. “The encouraging results of this study provide physicians and patients with a powerful, yet simple, nutritional tool in their fight against heart disease,” Dr. Ros concludes. Circulation. 2004;109:1609-1614 ================================ FACT: The Fattest industrialized nations with the greatest number of adolescents with BMI’s above the 85th percentile are 1) United States 2) Ireland 3) Greece and 4) Portugal.
The Skinniest adolescents, those countries with the lowest number of adolescents with BMI’s above the the 85th percentile are 1) Lithuania 2) Germany 3) France and 4) Belgium.
The U.S. Dept of Health and Human Services.