The latest research on nuts and cardiovascular disease risk is revealing rapid and significant beneficial effects, supporting the inclusion of nuts for a ‘heart healthy’ diet.
The effects of diet on cardiovascular disease risk are well established. Therefore, continued research into the effects of specific dietary components on cardiovascular health is important for identifying foods that should be included in a ‘heart healthy’ diet. Nuts have been receiving some attention in the fight against cardiovascular disease, and now the recommendation by the American Heart Association is to eat 4 servings (42g) of unsalted nuts per week. While there are some differences in the nutritional content of different nuts, most nuts contain at least some of the following nutrients that are beneficial for cardiovascular health: unsaturated fats, omega-3 fatty acids, fiber, vitamin E, plant sterols, and L-arginine.
A recent clinical trial conducted in Spain, demonstrated beneficial effects of nuts on cardiovascular health. There were 7,447 participants enrolled in the trial who were at high risk of, but did not currently have, cardiovascular disease. The participants were randomly assigned to one of three treatment groups. One group was assigned to a Mediterranean diet supplemented with nuts, another group was assigned to a Mediterranean diet supplemented with olive oil, and a third group was assigned to a reduced fat diet. The participants were followed for 4.8 years, with the primary endpoint being the rate of cardiovascular events. Secondary end points were stroke, myocardial infarction, death from cardiovascular causes, and death from any cause. Remarkably, there was a 30% reduction in risk of cardiovascular disease, and a 49% reduction in risk of stroke in the group assigned to the Mediterranean diet with nuts.
Another recent clinical trial on nuts and cardiovascular disease, conducted in the United States, assessed the effects of walnut consumption on biomarkers of cardiovascular health. This study assigned participants to three treatment groups whose diets were then supplemented with either walnut oil, walnut ‘meat’, or walnut skins. This study was the first to assess the cardio protective effects of the different components of walnuts. Overall, the study demonstrated beneficial effects of walnuts on heart rate, endothelial function, and cholesterol transport. The study found that walnut oil had a positive effect on endothelial function, when compared with either the whole walnut or the walnut skins. It also showed beneficial effects on cholesterol when consuming whole walnuts.
A clinical trial assessing nuts and cardiovascular disease is currently recruiting participants in Boston, Massachusetts, United States. This study will assess the beneficial effects of a pecan-supplemented diet on biomarkers of cardiovascular disease and type 2 diabetes risk. These measures of risk include:
oxidative stress, antioxidant activity, inflammation, endothelial function, and insulin resistance. These measures will be compared between two treatment groups. The first group of participants will consume 1.5 oz pecans per day for 28 days, while the second group of participants will not include nuts in their diet. The study will include men and women aged 50 years and over with a BMI between 25-35 kg/m2, and blood pressure between 120/80 and 159/99.
While these studies on nuts and cardiovascular disease continue to shed light on the beneficial effects of specific nuts on cardiovascular health, it seems clear that a diet supplemented with nuts is a reasonable way to protect heart health, and likely has other, yet un-researched health benefits.
Berryman, CE,Grieger, JA, West, SG, Chen, CYO, Blumberg, JB, Rothblat, GH, Sankaranarayanan, S, Kris-Etherton,PM.“Acute Consumption of Walnuts and Walnut Components Differentially Affect Postprandial Lipemia, Endothelial Function, Oxidative Stress, and Cholesterol Efflux in Humans with Mild Hypercholesterolemia”J. Nutr. June 1, 2013 vol. 143 no. 6 788-794.
Kris-Etherton, PM.“Walnuts Decrease Risk of Cardiovascular Disease: A Summary of Efficacy and Biologic Mechanisms”J. Nutr. April 1, 2014 vol. 144 no. 4 547S-554S.
Estruch, R, Ros, E, Salas-Salvadó, J,Covas, MI,Corella, D,Arós, F, Gómez-Gracia, E, Ruiz-Gutiérrez, V,Fiol, M,Lapetra, J, Lamuela-Raventos, RM, Serra-Majem, L,Pintó, X,Basora, J, Muñoz, MA,Sorlí, JV,Martínez, JA,Martínez-González, MA.“Primary Prevention of Cardiovascular Disease with a Mediterranean Diet”N Engl J Med 2013; 368:1279-1290April 4. 2013.
Panagiotakos, D“A Mediterranean diet supplemented with olive oil or nuts reduces the incidence of major cardiovascular events in high-risk patients”Evid Based Med 2014;19:10 doi:10.1136/eb-2013-101391.
Clinicaltrials.gov “Postprandial Effects of Walnut Components Versus Whole Walnuts on Cardiovascular Disease (CVD) RiskReduction” Available from:http://www.clinicaltrials.gov/ct2/show/NCT00938340?term=walnut&rank=8 Last Accessed: May 15, 2014.
Clinicaltrials.gov“The Effect of Pecans on Biomarkers of Risk for Cardiovascular Disease and Diabetes”Available from:http://www.clinicaltrials.gov/ct2/show/NCT01950806?term=nuts&recr=Open&no_unk=Y&rank=8 Last Accessed: May 15, 2014.
Image courtesy of Grant Cochrane / FreeDigitalPhotos.net
Written by Deborah Tallarigo, PhD