1. Home>
2. Specialties>
3. Women's Health>
4. Summary and Comment

Walnuts Can Benefit Your Blood Vessels

A walnut-enriched diet improved reactive vasodilation and lowered cholesterol levels more than a diet rich in olive oil did.

A diet containing a variety of nuts can reduce total and LDL cholesterol levels by as much as 15%, and populations that typically consume nuts have a lower risk for coronary artery disease. Although nuts contain a high proportion of fat, they are rich in unsaturated fat and also contain L-arginine, from which the endogenous vasodilator nitric oxide is derived. Walnuts in particular have a high content of -linolenic acid, a vegetable omega-3 fatty acid that might confer additional heart benefits. These investigators examined the impact of walnut consumption on endothelial function in a randomized, crossover study.

Twenty-one adults with LDL levels 130 mg/dL were assigned to follow a Mediterranean-type diet rich in olive oil (control diet), or a similar diet with 8 to 13 raw, shelled walnuts that accounted for 18% of the total daily calories and replaced approximately 32% of the calories from monosaturated fat in the control diet. After 4 weeks, participants crossed over to the other diet. Twenty subjects (60% women) completed both phases.

At the end of each diet period, brachial artery reactivity was measured by ultrasound 4 hours after participants consumed a prescribed meal that included olive oil (control diet) or walnuts (study diet). Reactive vasodilation improved significantly after the walnut meal compared with the olive oil meal (relative increase, 64%). In addition, mean total cholesterol level was significantly lower after the walnut diet than after the control diet (249 vs. 260 mg/dL), as was mean LDL level (167 vs. 179 mg/dL).

Comment: We must consider many factors when trying to identify the optimal diet for health. The emerging wisdom is moving away from the emphasis on reducing fat content and toward the concept that many foods confer physiologic benefits that might reduce future disease (see Journal Watch Women's Health Feb 5 2003). Clinicians should encourage patients to fit nuts, and walnuts in particular, into their total daily caloric allowance.

— Marian C. Limacher, MD

Published in Journal Watch Women's Health June 9, 2004

Citation(s):

Ros E et al. A walnut diet improves endothelial function in hypercholesterolemic subjects: A randomized crossover trial. Circulation 2004 Apr 6; 109:1609-14.

• Original article (Subscription may be required)
• Medline abstract (Free)