Nutrition Research Shows Pistachios are Smart for the Heart

12/04/08 More good news for pistachio fans! According to new data unveiled this week at the Experimental Biology Conference in San Diego, snacking on pistachios has proved once again to have a positive impact on improving cardiovascular health by significantly reducing inflammation in the body, a prominent cardiovascular disease (CVD) risk factor.

CVD remains the number one cause of death in the U.S., with millions more Americans currently living with the disease. A new study, led by researcher Dr. Penny Kris-Etherton from Penn State University's Department of Nutritional Sciences, looked at the effects of pistachios on multiple CVD risk factors, some of which include cholesterol, blood pressure and the genetic expression of various genes related to inflammation. The study positively suppsupp other recent studies that show a diet rich in pistachios packs a powerful nutrition punch.

"Pistachios contain many important nutrients that contribute to their positive effect on health. Every new study adds another piece to the puzzle of how eating pistachios may benefit heart health," said Dr. Constance Geiger, nutrition expert for the Western Pistachio Association (WPA).

The Penn State study was a randomized, crossover, controlled study of 28 healthy men and women (ages 30-70) with slightly-elevated cholesterol levels (similar to cholesterol levels of the general population). It tested three cholesterol-lowering diets, one without pistachio consumption and two with varied levels of pistachios in relation to total caloric intake (on average, 1.5 ounces and 3.0 ounces). All diets provided the same amount of saturated fat and cholesterol, but different amounts of unsaturated fat delivered by pistachios. Participants were fed the same diet for two weeks, which served as a baseline before the test diets began. Each subject tested all diets for a period of four weeks, and results were measured after each diet cycle was completed.

In addition to cholesterol measures (lipids and lipoproteins), blood pressure, heart rate, stroke volume, cardiac output and total resistance to blood flow through the vascular arteries were measured. At the end of each study period, cells were isolated from all subjects and genetic expression of inflammation markers was measured.

Study Highlights

Study results demonstrate the beneficial effects of a diet rich in pistachios on multiple CVD risk factors. As indicated in a previous release of this study, cholesterol levels, a prominent risk factor for CVD, improved with pistachio consumption. Compared to baseline, both the 1.5 and 3.0 ounce pistachio diets resulted in reduction of total cholesterol (TC) and low density lipoprotein cholesterol (LDL-C). In addition to the beneficial effects of pistachios on cholesterol, including pistachios as part of a heart-healthy diet also significantly reduced inflammation at the cellular level.

"Reducing inflammation at the cellular level is an important finding as it may be a more specific marker of inflammatory status than blood markers, which are general indicators of inflammation in the body," said Dr. Sarah Gebauer, Penn State University. "We are truly excited about these results and what they mean for those at risk for cardiovascular disease."

"As an organization dedicated to promoting nutrition news about pistachios and health, the WPA is already planning to fund additional research at Penn State and the University of Toronto," continued Dr. Geiger. "We hope to learn more about the effects of pistachios on blood pressure in people with diabetes and the effects of pistachios on satiety hormones and hormones that regulate blood sugar."

Pistachios Pack Powerful Nutrition

In July 2003, the U.S. FDA announced that eating most nuts, such as pistachios, may help reduce the risk of heart disease when eaten as part of a diet low in saturated fat and cholesterol. Since then, the U.S. pistachio industry has committed to learning more about the nutritional benefits of pistachios and the nuts impact on other health issues affecting Americans today.

In recent years, there has been other promising research showing the beneficial effects of consuming pistachios as part of a daily diet. The larger Penn State study that was originally released last spring and presented again in March 2008 showed that eating pistachios may reduce your body's response to the stresses of everyday life. The Penn State study entitled, "Pistachios Reduce Blood Pressure and Vascular Responses to Acute Stress in Healthy Adults," led by nutrition scientist Dr. Sheila G. West, found that lifestyle changes, along with a healthy diet and exercise, can lessen the biological reactions to stress. Pistachios, when eaten in both 3 ounce and 1.5 ounce servings, resulted in study participants experiencing a significant reduction of the biological effects of acute stress. During the diets supplemented with pistachios, subjects had lower blood pressure during stress. This study was relevant because lowering blood pressure may reduce the risk for stroke and heart disease.

The University of Toronto has also studied the effects of pistachios on diabetes - another major health issue in America today affecting 20.8 million children and adults - or 7 percent of the U.S. population (according to the American Diabetes Association). "Glycemic Response of Pistachios - A Dose Response Study and Effect of Pistachios Consumed with Different Common Carbohydrate Foods on Postprandial Glycemia," led by University of Toronto's Dr. Cyril Kendall and Dr. David Jenkins, found that pistachios, when eaten with some common high-carbohydrate foods, may actually slow the absorption of carbohydrates into the body, resulting in a lower than expected blood sugar level. Certain carbohydrates elevate blood sugar levels more quickly than foods that contain higher levels of protein, fiber and monounsaturated fat, like pistachios. In general, foods that do not quickly raise blood sugar are often considered healthier than their more processed counterparts. The study is the first of its kind to examine the effects of pistachios alone and in combination with carbohydrates on blood sugar levels. The study hopefully will lead to new treatment methods and management of diabetes.