New Research Unveiled in The Journal of Nutrition Reveals Pistachios Protect the Heart in a New Way

Rigorous Study Shows "The Green Nut" is Rich with Antioxidants Linking Consumption to Reduced Risk of Cardiovascular Disease

FRESNO, CA (May 20, 2010) -- Growing evidence continues to build about the many benefits of consuming pistachios on a daily basis. New research published today in The Journal of Nutrition demonstrates that antioxidants in pistachios help reduce the risk of heart disease. This most recent nationally published study conducted by nutrition scientists at Penn State University shows that eating pistachios daily has cardioprotective effects due to the rich antioxidant content which may help lower oxidized-LDL (bad) cholesterol levels.

Dr. Penny Kris-Etherton, lead researcher for this study at Penn State University, conducted a carefully controlled dose-response trial to evaluate the effect of pistachio consumption on serum antioxidant status and oxidative biomarkers (oxidized-LDL cholesterol) of cardiovascular disease. Results suggest that incorporating pistachios into a healthy diet helps reduce oxidized-LDL cholesterol, both as a result of LDL cholesterol lowering and because pistachios increase antioxidants in the blood.

Eating pistachios daily increased serum antioxidants in study participants, such as lutein and gamma tocopherol, and decreased oxidized-LDL, when compared to a low-fat control diet without pistachios. Higher amounts of oxidized-LDL and fat-breakdown products are found in atherosclerotic plaques. These substances are thought to play a role in development and progression of atherosclerosis, the collection of fatty materials along the arteries. Lowering oxidized- LDL decreases the risk of heart disease. Pistachios’ positive effects on many heart disease risk factors likely reduce overall heart disease risk more than just a decrease in total and LDL cholesterol alone.

"In the past, many studies have focused on the role of lipids and cholesterol in heart disease," said Dr. Penny Kris-Etherton, researcher at Penn State University’s Department of Nutritional Sciences. "Pistachios are the only nut that give you significant amounts of lutein and zeazanthin -- 342 mg per ounce. They also provide 6.4 mg of gamma tocopherol. This study validates the significant antioxidant benefits of consuming pistachios. We plan to continue to explore the positive role pistachios play in the American diet."

This is the third study conducted by Penn State’s lead nutrition science researchers that correlates pistachio consumption and heart disease prevention. In 2008, results from a Penn State study (Gebaurer, et al 2008) demonstrated that regular consumption of pistachios had cholesterol lowering effects. Pistachios lower total and LDL cholesterol levels, which are important factors in reducing the risk of heart disease.

In 2009, Penn State revealed the results of a second study finding that pistachios have beneficial anti-inflammatory properties. Inflammation is a newly discovered risk factor for heart disease, as well as other chronic diseases. Dr. Kris-Etherton’s latest research is now indicating that pistachios work on a third level to reduce the risk of heart disease, by increasing serum antioxidants and reducing oxidized- LDL.

Antioxidant Study Method

Participants began the current study by eating a typical American diet consisting of 35 percent total fat and 11 percent saturated fat for two weeks. They then tested three diets for four weeks, each with approximately a two-week break between each diet. All three diets were variations on the Step I Diet, a cholesterol-lowering diet in general use. The diets included, as a control, a Step I Diet with no pistachios and about 25 percent total fat and 8 percent saturated fat. The pistachio-enhanced diets were Step I Diets combined with 10 percent (about 1.5 ounces of pistachios) and 20 percent (about 3 ounces of pistachios) of the calories supplied by pistachio nuts, respectively. The 10 percent pistachio diet had 30 percent total fat and 8 percent saturated fat, and the 20 percent pistachio diet had 34 percent total fat and 8 percent saturated fat.

The participants ate half their pistachios as a snack and incorporated the rest into meals.

All the test diets had the same amount of saturated fat and cholesterol, and varied in the amount of unsaturated fat provided by the pistachios. The diets were matched for antioxidants A, C, lutein and tocopherols.

The Results

Antioxidants were significantly increased after eating pistachios, including lutein, gamma tocopherol, alpha carotene and beta carotene. Lutein, alpha and beta carotene were greater after eating both 10 percent and 20 percent pistachios diets, compared to the average American diet without pistachios. Gamma tocopherol was significantly higher after the 20 percent pistachio diet. Oxidized-LDL was significantly lower after the 20 percent pistachio diet. This decrease in oxidized-LDL correlated with the significant increases in the antioxidants lutein and gamma tocopherol.

The Research

The research was published in an article entitled, "Pistachios increase serum antioxidants and reduce serum oxidized-LDL in hypercholesterolemic aduts." C.D. Kay, Ph.D., S. K. Gebauer, Ph.D., Sheila G. West, Ph.D., P.M. Kris-Etherton, Ph.D., Department of Nutritional Sciences, Department of Biobehavioral Health, and Integrative Biosciences, The Pennsylvania State University, University Park, PA. (2010).

Pistachios Facts

Pistachios are a naturally cholesterol-free snack that contains just 1.5 grams of saturated fat and 13 grams of fat, the majority of which comes from monounsaturated fat. A one-ounce serving of pistachios equals 49 nuts, which is more nuts per serving than any other snack nut. One serving of pistachios has as much potassium (300mg, 8 percent) as an orange (250mg, 7 percent), making it a nutritious snack choice or ingredient to incorporate into daily diets.

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The Green Nut The Green Nut™ and TheGreenNut.org is a nutrition awareness campaign sponsored by the Western Pistachio Association (WPA). Based in Fresno, California, the WPA is a voluntary association representing pistachio growers throughout the country. Founded in 1980, it is the only voluntary organization representing U.S. pistachio growers’ interests. It is governed by an 18 member board elected from a variety of states with the shared goal of increasing national awareness about the nutritional benefits of U.S. grown pistachios. For more healthy tips, visit www.thegreennut.org, or follow The Green Nut on Twitter at http://twitter.com/thegreennut.