Walnuts and Artery Function

Image Credit: Martin Fisch / Flickr. This image has been modified.

Do Walnuts Really Improve Artery Function?

Good news for nut lovers: Eating at least one serving of walnuts per week may drop our chances of a cardiovascular-related death by 50%. However, walnut consumption may only drop our cholesterol levels about 5%. How could we get a 50% drop in cardiac mortality from just a 5% drop in cholesterol? Walnuts must have some other heart-protecting benefits besides lowering cholesterol.

The ability of blood vessels to relax and open normally is considered an excellent barometer of underlying vascular health. For example, even after controlling for other risk factors, 80% of those with better than average arterial function survived cardiac event-free over the years, whereas 80% of those with below average dilation didn’t. So what effect do nuts have? A 2011 review in the journal Nutrition, Metabolism, and Cardiovascular Diseases found five clinical trials analyzing the effect of nut consumption on arterial function, and all three studies on walnuts showed an improvement in endothelial function measured in the arm. The study on pistachios also found a positive effect, but the study on hazelnuts was a wash.

A subsequent study on hazelnuts, however, did find a significant improvement in arterial function, so the data for hazelnuts is mixed, whereas two subsequent walnut studies (highlighted in my video, Walnuts and Artery Function) confirmed walnuts’ benefits. Therefore, eight studies to date have investigated the effect of nuts on brachial artery function; seven out of eight showed a significant improvement in arterial function, one showed a negligible effect, and none found nuts made things worse.

Half the studies, though, used the added nuts to replace foods in the diet known to have a negative effect on endothelial function. For example, in one study, walnuts replaced meat and dairy, which have been shown to be detrimental, so no wonder arterial function got better. When we do a study like that, we can’t tell if the benefits are because of the addition of the good stuff or the removal of the bad. In three of the other studies, nuts replaced olive oil, which tends to lead to a worsening of endothelial function. Therefore, in these four studies, the beneficial effects of the walnuts may have been exaggerated.

However, the other four studies just added nuts as a snack or with a meal, without replacing any specific foods, and found that nuts significantly improved arterial functioning. Given their association with longevity (see Nuts May Help Prevent Death), I encourage everyone to eat an ounce of nuts a day (unless of course you’re allergic). Only about 1% of people report nut allergies, but still, that eliminates nut consumption for millions of Americans.

What else can nuts do? See, for example:

Don’t nuts make us fat, though? You may be surprised—see Nuts and Obesity: The Weight of Evidence.

Which type of walnut is better? Black Versus English Walnuts.

What about the phytates in nuts–do we need to soak or toast them? See:

-Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my videos for free by clicking here and watch my full 2012 – 2015 presentations Uprooting the Leading Causes of Death, More than an Apple a Day, From Table to Able, and Food as Medicine.

Comenta

Michael Greger M.D., FACLM

Michael Greger, M.D. FACLM, is a physician, New York Times bestselling author, and internationally recognized professional speaker on a number of important public health issues. Dr. Greger has lectured at the Conference on World Affairs, the National Institutes of Health, and the International Bird Flu Summit, testified before Congress, appeared on The Dr. Oz Show and The Colbert Report, and was invited as an expert witness in defense of Oprah Winfrey at the infamous "meat defamation" trial.


Comment Etiquette

On NutritionFacts.org, you'll find a vibrant community of nutrition enthusiasts, health professionals, and many knowledgeable users seeking to discover the healthiest diet to eat for themselves and their families. As always, our goal is to foster conversations that are insightful, engaging, and most of all, helpful – from the nutrition beginners to the experts in our community.

To do this we need your help, so here are some basic guidelines to get you started.

The Short List

To help maintain and foster a welcoming atmosphere in our comments, please refrain from rude comments, name-calling, and responding to posts that break the rules (see our full Community Guidelines for more details). We will remove any posts in violation of our rules when we see it, which will, unfortunately, include any nicer comments that may have been made in response.

Be respectful and help out our staff and volunteer health supporters by actively not replying to comments that are breaking the rules. Instead, please flag or report them by submitting a ticket to our help desk. NutritionFacts.org is made up of an incredible staff and many dedicated volunteers that work hard to ensure that the comments section runs smoothly and we spend a great deal of time reading comments from our community members.

Have a correction or suggestion for video or blog? Please contact us to let us know. Submitting a correction this way will result in a quicker fix than commenting on a thread with a suggestion or correction.

View the Full Community Guidelines

Deja una respuesta

Tu correo electrónico no se publicará Los campos obligatorios están marcados *

Pin It en Pinterest

Share This