New Study from
Barcelona, Spain Shows Eating Walnuts Reduces Artery Damage
(BARCELONA, SPAIN) APRIL 26, 2004 - A new
clinical study shows that substituting walnuts for monounsaturated
fat in a Mediterranean diet improves, and even restores, endothelial
function (the property of arteries to dilate in order to meet an
increased demand of blood, for instance due to a physical effort).
Walnuts also reduce harmful cell adhesion molecules which are
associated with atherosclerosis, commonly known as hardening of the
arteries. These dual effects enhance the circulatory system,
therefore aiding in the prevention of heart disease.
Published in today’s issue of Circulation: Journal
of the American Heart Association, the study concludes that the
results provide further support for the inclusion of walnuts in
healthy diets. “This is the first time a whole food, not its
isolated components, has shown this beneficial effect on vascular
health,” according to Emilio Ros, M.D., the Hospital Clinic of
Barcelona, researcher who directed the study. Dr. Ros notes,
“Compared with the Mediterranean diet, the walnut diet increased
endothelium-dependent vasodilation by 64 percent and reduced levels
of vascular cell adhesion molecule-1 by 20 percent. In addition, as
in previous studies, the walnut diet decreased total cholesterol and
LDL cholesterol.”
Dr. Ros cites the powerful nutrient profile of walnuts as providing
this capacity to improve vascular elasticity. Specifically, he notes
that, “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.” He
also references the amino acid L-arginine, and the gamma-tocopherol
form of vitamin-E, both of which walnuts are rich in, as effective
in preventing harmful vascular blockage.
“To put it simply, a healthy artery is like an elastic rubber pipe
that allows changes in flow, while an artery with impaired
endothelial function is like a rigid lead pipe that has a constant
flow. The walnut diet in this study actually restored the elasticity
of the artery, allowing increased blood flow on demand,” explains
Dr. Ros. “Anyone who has risk factors for heart disease, such as
smoking, high blood cholesterol, diabetes, hypertension or obesity,
is in a situation where the arteries do not dilate properly when
they need to. That's what is called endothelial dysfunction. The
patients in our study had high blood cholesterol, a known cause of
endothelial dysfunction, and this abnormality was corrected by the
walnut diet. The encouraging results of this study provide
physicians and patients with a powerful, yet simple, nutritional
tool in their fight against heart disease,” he says.
Conducted by the Lipid Clinic at the Hospital Clinic of Barcelona,
the study is entitled, “A walnut diet improves endothelial
function in hypercholesterolemic subjects: a randomized crossover
trial.” 21 men and women (ages 25-75) with high cholesterol
followed a cholesterol-lowering Mediteranean diet, and a diet of
similar energy and fat content in which approximately 1.4-2.3 ounces
of walnuts daily (equivalent to 40-65 grams or 8-13 walnuts), based
on subjects’ total caloric intake, replaced roughly 32 percent of
the energy from monounsaturated fat. Participants followed each diet
for four weeks.
Co-investigators in this study include Isabel Nunez, MD; Ana Perez-Heras,
RD; Merce Serra, RD; Rosa Gilabert, MD; Elena Casals, MD; Ramon
Deulofeu, MD. |