Latest Pistachio Study Reveals Significant Reduction in Markers of Inflammation - an Emerging Risk Factor in Heart Disease

Pistachios when paired with a healthy diet significantly reduce markers of inflammation at the cellular level when compared to an average American diet. High levels of inflammation are related to the development of heart disease.

28/10/08 According to new data presented yesterday at the American Dietetic Association's (ADA) Food & Nutrition Conference & Expo (FNCE) in Chicago, pistachios -- when paired with a healthy diet -- significantly reduce markers of inflammation at the cellular level when compared to an average American diet. High levels of inflammation are related to the development of heart disease -- the number one cause of death in the U.S. -- and other chronic conditions. The data conducted by Penn State University was presented on Sunday, October 26.

"In addition to the effect of pistachio-rich diets on markers of inflammation, we also found that diet-induced changes in gene expression may help explain changes in heart disease risk factors following consumption of pistachio-rich diets," says Sarah Gebauer, recent Penn State Ph.D. recipient, currently a post-doctoral research associate, USDA Beltsville Human Nutrition Research Center. "This is a very exciting time for both researchers and the general public. Our continued research surrounding the health benefits of pistachios is leading to significant findings that will inevitably help people reduce common risk factors that may lead to heart disease."

The new groundbreaking study led by Penny Kris-Etherton, Distinguished Professor of Nutrition, Penn State University, examined changes in inflammation-related gene expression (changes varied according to diet) and evaluated the effects of pistachio-rich diets on heart disease risk factors in subjects with moderately elevated LDL-cholesterol ("bad cholesterol"). Participants in this randomized, crossover, controlled-feeding study followed three different diets -- one without pistachios, and two with different levels of pistachio consumption (approximately 1.5 oz and 3.0 oz). The study positively supports other recent studies that show a diet rich in pistachios helps improve heart disease risk factors, in this case, inflammation. It also furthered researchers' understanding of differences in response to diet. Some individuals were responsive to diet changes while others were not. More research is needed to further understand the reasoning behind diet responders versus non-responders. Ultimately, this will lead to a more individualized approach for dietary guidance.

Study Highlights

-- Diets that incorporate pistachios significantly reduce the expression of inflammation-related genes when compared to an average American diet (higher in total fat and saturated fat).

-- Responses to diet changes are variable -- some individuals are diet-responsive while others are not. Further research is needed to better understand reasons for responders versus non-responders.

-- Following consumption of the pistachio diets, some individuals had diet-induced changes (diet responders) in cholesteryl ester transfer protein (CETP) -- a key protein involved in cholesterol metabolism.

-- In diet responders, changes in CETP expression at the cellular level indicated changes in heart disease risk factors in the blood -- such as LDL-cholesterol. Results suggest that changes in gene expression may help explain changes in heart disease risk factors following consumption of pistachio diets.

"The Western Pistachio Association is dedicated to funding research and promoting nutrition news about pistachios and health," says Dr. Constance Geiger, nutrition expert for the Western Pistachio Association (WPA). "We're eager to fund additional research that will look at the effect of pistachios on prevention of chronic disease risk factors, which will help to better-predict positive changes within the body."

Pistachios Pack Powerful Nutrition

In July 2003, the U.S. Food and Drug Administration (FDA) announced that eating most nuts, such as pistachios, may help reduce the risk of heart disease when consumed as part of a diet low in saturated fat and cholesterol. Since then, the Western Pistachio Association 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, other research has shown the beneficial effects of consuming pistachios as part of a daily diet. The larger study conducted by Penn State 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 consumed 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 is 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 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 consumed 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 may lead to new treatment methods and man gement of diabetes.